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  <link href="https://datatracker.ietf.org/doc/draft-ietf-anima-autonomic-control-plane-30" rel="prev"/>
  <link href="https://dx.doi.org/10.17487/rfc8994" rel="alternate"/>
  <link href="urn:issn:2070-1721" rel="alternate"/>
  <front>
    <title abbrev="An Autonomic Control Plane (ACP)">An Autonomic Control Plane (ACP)</title>
    <seriesInfo name="Internet-Draft" value="draft-ietf-anima-autonomic-control-plane-30"/> name="RFC" value="8994" stream="IETF"/>
    <author role="editor" fullname="Toerless Eckert" surname="Eckert">
      <organization abbrev="Futurewei USA">
                                Futurewei USA" showOnFrontPage="true">Futurewei Technologies Inc. USA</organization>
      <address>
        <postal>
          <street>2330 Central Expy</street>
          <city>Santa Clara</city>
          <region>CA</region>
          <code>95050</code>
          <country>USA</country>
          <country>United States of America</country>
        </postal>
        <email>tte+ietf@cs.fau.de</email>
      </address>
    </author>
    <author role="editor" fullname="Michael H. Behringer" initials="M." surname="Behringer">
      <address>
        <email>michael.h.behringer@gmail.com</email>
      </address>
    </author>
    <author fullname="Steinthor Bjarnason" initials="S." surname="Bjarnason">
      <organization>Arbor
      <organization showOnFrontPage="true">Arbor Networks</organization>
      <address>
        <postal>
          <street>2727 South State Street, Suite 200</street>
          <city>Ann Arbor</city>
          <code>MI 48104</code>
          <region>MI</region>
          <code>48104</code>
          <country>United States</country> States of America</country>
        </postal>
        <email>sbjarnason@arbor.net</email>
      </address>
    </author>
    <date month="Oct" day="30" year="2020"/> month="05" year="2021"/>
    <area>Operations and Management</area>
    <workgroup>ANIMA WG</workgroup>
    <abstract>
      <t>
    <workgroup>ANIMA</workgroup>
    <keyword>addressing-scheme</keyword>
    <keyword>ANI</keyword>
    <keyword>autonomic networking</keyword>
    <keyword>autonomous operation</keyword>
    <keyword>BRSKI</keyword>
    <keyword>certificate</keyword>
    <keyword>Data-Plane</keyword>
    <keyword>domain</keyword>
    <keyword>DTLS</keyword>
    <keyword>DULL</keyword>
    <keyword>EST</keyword>
    <keyword>GRASP</keyword>
    <keyword>IDevID</keyword>
    <keyword>inband</keyword>
    <keyword>IPsec</keyword>
    <keyword>IPv6</keyword>
    <keyword>LDevID</keyword>
    <keyword>loopback-interface</keyword>
    <keyword>NOC</keyword>
    <keyword>OAM</keyword>
    <keyword>out-of-band</keyword>
    <keyword>registrar</keyword>
    <keyword>renewal</keyword>
    <keyword>RPL</keyword>
    <keyword>secure</keyword>
    <keyword>self-management</keyword>
    <keyword>ULA</keyword>
    <keyword>VPN</keyword>
    <keyword>VRF</keyword>
    <keyword/>
    <abstract pn="section-abstract">
      <t indent="0" pn="section-abstract-1">
                                Autonomic functions need a control plane to communicate, which depends on some addressing and routing.  This Autonomic Control Plane should ideally be self-managing, self-managing and be as independent as possible of configuration.  This document defines such a plane and calls it the "Autonomic Control Plane", with the primary use as a control plane for autonomic functions.  It also serves as a "virtual out-of-band channel" for Operations, Administration Administration, and Management (OAM) communications over a network that provides automatically configured configured, hop-by-hop authenticated and encrypted communications via automatically configured IPv6 even when the network is not configured, configured or is misconfigured.
      </t>
    </abstract>
  </front>
  <middle>
    <boilerplate>
      <section anchor="intro" numbered="true" toc="default">
      <name>Introduction (Informative)</name>
      <t>Autonomic Networking anchor="status-of-memo" numbered="false" removeInRFC="false" toc="exclude" pn="section-boilerplate.1">
        <name slugifiedName="name-status-of-this-memo">Status of This Memo</name>
        <t indent="0" pn="section-boilerplate.1-1">
            This is an Internet Standards Track document.
        </t>
        <t indent="0" pn="section-boilerplate.1-2">
            This document is a concept product of self-management: Autonomic functions self-configure, and negotiate parameters and settings across the network. <xref target="RFC7575" format="default"/> defines Internet Engineering Task Force
            (IETF).  It represents the fundamental ideas and design goals of Autonomic Networking.  A gap analysis consensus of Autonomic Networking is given in <xref target="RFC7576" format="default"/>.  The reference architecture for Autonomic Networking in the IETF is specified in the document <xref target="I-D.ietf-anima-reference-model" format="default"/>.</t>
      <t>Autonomic functions need an autonomically built communications infrastructure.  This infrastructure needs to be secure, resilient community.  It has
            received public review and re-usable has been approved for publication by all autonomic functions.
            the Internet Engineering Steering Group (IESG).  Further
            information on Internet Standards is available in Section 5 2 of <xref target="RFC7575" format="default"/> introduces that infrastructure and calls it
            RFC 7841.
        </t>
        <t indent="0" pn="section-boilerplate.1-3">
            Information about the Autonomic Control Plane (ACP).  More descriptively current status of this document, any
            errata, and how to provide feedback on it would may be the "Autonomic communications infrastructure for OAM obtained at
            <eref target="https://www.rfc-editor.org/info/rfc8994" brackets="none"/>.
        </t>
      </section>
      <section anchor="copyright" numbered="false" removeInRFC="false" toc="exclude" pn="section-boilerplate.2">
        <name slugifiedName="name-copyright-notice">Copyright Notice</name>
        <t indent="0" pn="section-boilerplate.2-1">
            Copyright (c) 2021 IETF Trust and Control".  For naming consistency with that prior document, this document continues to use the name ACP though.</t>
      <t>Today, persons identified as the OAM and control plane of IP networks is what
            document authors. All rights reserved.
        </t>
        <t indent="0" pn="section-boilerplate.2-2">
            This document is typically called in-band management/signaling: Its management subject to BCP 78 and control protocol traffic depends the IETF Trust's Legal
            Provisions Relating to IETF Documents
            (<eref target="https://trustee.ietf.org/license-info" brackets="none"/>) in effect on the routing and forwarding tables, security, policy, QoS date of
            publication of this document. Please review these documents
            carefully, as they describe your rights and potentially other configuration that first has restrictions with
            respect to be established through this document. Code Components extracted from this
            document must include Simplified BSD License text as described in
            Section 4.e of the very same management Trust Legal Provisions and control protocols. Misconfigurations including unexpected side effects or mutual dependences can disrupt OAM are provided without
            warranty as described in the Simplified BSD License.
        </t>
      </section>
    </boilerplate>
    <toc>
      <section anchor="toc" numbered="false" removeInRFC="false" toc="exclude" pn="section-toc.1">
        <name slugifiedName="name-table-of-contents">Table of Contents</name>
        <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1">
          <li pn="section-toc.1-1.1">
            <t indent="0" keepWithNext="true" pn="section-toc.1-1.1.1"><xref derivedContent="1" format="counter" sectionFormat="of" target="section-1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-introduction-informative">Introduction (Informative)</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.1.2">
              <li pn="section-toc.1-1.1.2.1">
                <t indent="0" keepWithNext="true" pn="section-toc.1-1.1.2.1.1"><xref derivedContent="1.1" format="counter" sectionFormat="of" target="section-1.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-applicability-and-scope">Applicability and control operations Scope</xref></t>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.2">
            <t indent="0" keepWithNext="true" pn="section-toc.1-1.2.1"><xref derivedContent="2" format="counter" sectionFormat="of" target="section-2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acronyms-and-terminology-in">Acronyms and especially disrupt remote management access to Terminology (Informative)</xref></t>
          </li>
          <li pn="section-toc.1-1.3">
            <t indent="0" pn="section-toc.1-1.3.1"><xref derivedContent="3" format="counter" sectionFormat="of" target="section-3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-use-cases-for-an-autonomic-">Use Cases for an Autonomic Control Plane (Informative)</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.3.2">
              <li pn="section-toc.1-1.3.2.1">
                <t indent="0" pn="section-toc.1-1.3.2.1.1"><xref derivedContent="3.1" format="counter" sectionFormat="of" target="section-3.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-an-infrastructure-for-auton">An Infrastructure for Autonomic Functions</xref></t>
              </li>
              <li pn="section-toc.1-1.3.2.2">
                <t indent="0" pn="section-toc.1-1.3.2.2.1"><xref derivedContent="3.2" format="counter" sectionFormat="of" target="section-3.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-secure-bootstrap-over-an-un">Secure Bootstrap over an Unconfigured Network</xref></t>
              </li>
              <li pn="section-toc.1-1.3.2.3">
                <t indent="0" pn="section-toc.1-1.3.2.3.1"><xref derivedContent="3.3" format="counter" sectionFormat="of" target="section-3.3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-permanent-reachability-inde">Permanent Reachability Independent of the affected node itself and potentially a much larger number Data Plane</xref></t>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.4">
            <t indent="0" pn="section-toc.1-1.4.1"><xref derivedContent="4" format="counter" sectionFormat="of" target="section-4"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-requirements-informative">Requirements (Informative)</xref></t>
          </li>
          <li pn="section-toc.1-1.5">
            <t indent="0" pn="section-toc.1-1.5.1"><xref derivedContent="5" format="counter" sectionFormat="of" target="section-5"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-overview-informative">Overview (Informative)</xref></t>
          </li>
          <li pn="section-toc.1-1.6">
            <t indent="0" pn="section-toc.1-1.6.1"><xref derivedContent="6" format="counter" sectionFormat="of" target="section-6"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-self-creation-of-an-autonom">Self-Creation of nodes an Autonomic Control Plane (ACP) (Normative)</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.6.2">
              <li pn="section-toc.1-1.6.2.1">
                <t indent="0" pn="section-toc.1-1.6.2.1.1"><xref derivedContent="6.1" format="counter" sectionFormat="of" target="section-6.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-requirements-for-the-use-of">Requirements for whom the affected node is on the network path.</t>

<t>For an example Use of inband management failing Transport Layer Security (TLS)</xref></t>
              </li>
              <li pn="section-toc.1-1.6.2.2">
                <t indent="0" pn="section-toc.1-1.6.2.2.1"><xref derivedContent="6.2" format="counter" sectionFormat="of" target="section-6.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-domain-certificate-and-">ACP Domain, Certificate, and Network</xref></t>
                <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.6.2.2.2">
                  <li pn="section-toc.1-1.6.2.2.2.1">
                    <t indent="0" pn="section-toc.1-1.6.2.2.2.1.1"><xref derivedContent="6.2.1" format="counter" sectionFormat="of" target="section-6.2.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-certificates">ACP Certificates</xref></t>
                  </li>
                  <li pn="section-toc.1-1.6.2.2.2.2">
                    <t indent="0" pn="section-toc.1-1.6.2.2.2.2.1"><xref derivedContent="6.2.2" format="counter" sectionFormat="of" target="section-6.2.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-certificate-acpnodename">ACP Certificate AcpNodeName</xref></t>
                    <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.6.2.2.2.2.2">
                      <li pn="section-toc.1-1.6.2.2.2.2.2.1">
                        <t indent="0" pn="section-toc.1-1.6.2.2.2.2.2.1.1"><xref derivedContent="6.2.2.1" format="counter" sectionFormat="of" target="section-6.2.2.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acpnodename-asn1-module">AcpNodeName ASN.1 Module</xref></t>
                      </li>
                    </ul>
                  </li>
                  <li pn="section-toc.1-1.6.2.2.2.3">
                    <t indent="0" pn="section-toc.1-1.6.2.2.2.3.1"><xref derivedContent="6.2.3" format="counter" sectionFormat="of" target="section-6.2.3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-domain-membership-check">ACP Domain Membership Check</xref></t>
                    <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.6.2.2.2.3.2">
                      <li pn="section-toc.1-1.6.2.2.2.3.2.1">
                        <t indent="0" pn="section-toc.1-1.6.2.2.2.3.2.1.1"><xref derivedContent="6.2.3.1" format="counter" sectionFormat="of" target="section-6.2.3.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-realtime-clock-and-time-val">Realtime Clock and Time Validation</xref></t>
                      </li>
                    </ul>
                  </li>
                  <li pn="section-toc.1-1.6.2.2.2.4">
                    <t indent="0" pn="section-toc.1-1.6.2.2.2.4.1"><xref derivedContent="6.2.4" format="counter" sectionFormat="of" target="section-6.2.4"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-trust-anchors-ta">Trust Anchors (TA)</xref></t>
                  </li>
                  <li pn="section-toc.1-1.6.2.2.2.5">
                    <t indent="0" pn="section-toc.1-1.6.2.2.2.5.1"><xref derivedContent="6.2.5" format="counter" sectionFormat="of" target="section-6.2.5"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-certificate-and-trust-ancho">Certificate and Trust Anchor Maintenance</xref></t>
                    <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.6.2.2.2.5.2">
                      <li pn="section-toc.1-1.6.2.2.2.5.2.1">
                        <t indent="0" pn="section-toc.1-1.6.2.2.2.5.2.1.1"><xref derivedContent="6.2.5.1" format="counter" sectionFormat="of" target="section-6.2.5.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-grasp-objective-for-est-ser">GRASP Objective for EST Server</xref></t>
                      </li>
                      <li pn="section-toc.1-1.6.2.2.2.5.2.2">
                        <t indent="0" pn="section-toc.1-1.6.2.2.2.5.2.2.1"><xref derivedContent="6.2.5.2" format="counter" sectionFormat="of" target="section-6.2.5.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-renewal">Renewal</xref></t>
                      </li>
                      <li pn="section-toc.1-1.6.2.2.2.5.2.3">
                        <t indent="0" pn="section-toc.1-1.6.2.2.2.5.2.3.1"><xref derivedContent="6.2.5.3" format="counter" sectionFormat="of" target="section-6.2.5.3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-certificate-revocation-list">Certificate Revocation Lists (CRLs)</xref></t>
                      </li>
                      <li pn="section-toc.1-1.6.2.2.2.5.2.4">
                        <t indent="0" pn="section-toc.1-1.6.2.2.2.5.2.4.1"><xref derivedContent="6.2.5.4" format="counter" sectionFormat="of" target="section-6.2.5.4"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-lifetimes">Lifetimes</xref></t>
                      </li>
                      <li pn="section-toc.1-1.6.2.2.2.5.2.5">
                        <t indent="0" pn="section-toc.1-1.6.2.2.2.5.2.5.1"><xref derivedContent="6.2.5.5" format="counter" sectionFormat="of" target="section-6.2.5.5"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-reenrollment">Reenrollment</xref></t>
                      </li>
                      <li pn="section-toc.1-1.6.2.2.2.5.2.6">
                        <t indent="0" pn="section-toc.1-1.6.2.2.2.5.2.6.1"><xref derivedContent="6.2.5.6" format="counter" sectionFormat="of" target="section-6.2.5.6"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-failing-certificates">Failing Certificates</xref></t>
                      </li>
                    </ul>
                  </li>
                </ul>
              </li>
              <li pn="section-toc.1-1.6.2.3">
                <t indent="0" pn="section-toc.1-1.6.2.3.1"><xref derivedContent="6.3" format="counter" sectionFormat="of" target="section-6.3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-adjacency-table">ACP Adjacency Table</xref></t>
              </li>
              <li pn="section-toc.1-1.6.2.4">
                <t indent="0" pn="section-toc.1-1.6.2.4.1"><xref derivedContent="6.4" format="counter" sectionFormat="of" target="section-6.4"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-neighbor-discovery-with-dul">Neighbor Discovery with DULL GRASP</xref></t>
              </li>
              <li pn="section-toc.1-1.6.2.5">
                <t indent="0" pn="section-toc.1-1.6.2.5.1"><xref derivedContent="6.5" format="counter" sectionFormat="of" target="section-6.5"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-candidate-acp-neighbor-sele">Candidate ACP Neighbor Selection</xref></t>
              </li>
              <li pn="section-toc.1-1.6.2.6">
                <t indent="0" pn="section-toc.1-1.6.2.6.1"><xref derivedContent="6.6" format="counter" sectionFormat="of" target="section-6.6"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-channel-selection">Channel Selection</xref></t>
              </li>
              <li pn="section-toc.1-1.6.2.7">
                <t indent="0" pn="section-toc.1-1.6.2.7.1"><xref derivedContent="6.7" format="counter" sectionFormat="of" target="section-6.7"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-candidate-acp-neighbor-veri">Candidate ACP Neighbor Verification</xref></t>
              </li>
              <li pn="section-toc.1-1.6.2.8">
                <t indent="0" pn="section-toc.1-1.6.2.8.1"><xref derivedContent="6.8" format="counter" sectionFormat="of" target="section-6.8"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-security-association-secure">Security Association (Secure Channel) Protocols</xref></t>
                <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.6.2.8.2">
                  <li pn="section-toc.1-1.6.2.8.2.1">
                    <t indent="0" pn="section-toc.1-1.6.2.8.2.1.1"><xref derivedContent="6.8.1" format="counter" sectionFormat="of" target="section-6.8.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-general-considerations">General Considerations</xref></t>
                  </li>
                  <li pn="section-toc.1-1.6.2.8.2.2">
                    <t indent="0" pn="section-toc.1-1.6.2.8.2.2.1"><xref derivedContent="6.8.2" format="counter" sectionFormat="of" target="section-6.8.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-common-requirements">Common Requirements</xref></t>
                  </li>
                  <li pn="section-toc.1-1.6.2.8.2.3">
                    <t indent="0" pn="section-toc.1-1.6.2.8.2.3.1"><xref derivedContent="6.8.3" format="counter" sectionFormat="of" target="section-6.8.3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-via-ipsec">ACP via IPsec</xref></t>
                    <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.6.2.8.2.3.2">
                      <li pn="section-toc.1-1.6.2.8.2.3.2.1">
                        <t indent="0" pn="section-toc.1-1.6.2.8.2.3.2.1.1"><xref derivedContent="6.8.3.1" format="counter" sectionFormat="of" target="section-6.8.3.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-native-ipsec">Native IPsec</xref></t>
                        <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.6.2.8.2.3.2.1.2">
                          <li pn="section-toc.1-1.6.2.8.2.3.2.1.2.1">
                            <t indent="0" pn="section-toc.1-1.6.2.8.2.3.2.1.2.1.1"><xref derivedContent="6.8.3.1.1" format="counter" sectionFormat="of" target="section-6.8.3.1.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-rfc-8221-ipsec-esp">RFC 8221 (IPsec/ESP)</xref></t>
                          </li>
                          <li pn="section-toc.1-1.6.2.8.2.3.2.1.2.2">
                            <t indent="0" pn="section-toc.1-1.6.2.8.2.3.2.1.2.2.1"><xref derivedContent="6.8.3.1.2" format="counter" sectionFormat="of" target="section-6.8.3.1.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-rfc-8247-ikev2">RFC 8247 (IKEv2)</xref></t>
                          </li>
                        </ul>
                      </li>
                      <li pn="section-toc.1-1.6.2.8.2.3.2.2">
                        <t indent="0" pn="section-toc.1-1.6.2.8.2.3.2.2.1"><xref derivedContent="6.8.3.2" format="counter" sectionFormat="of" target="section-6.8.3.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-ipsec-with-gre-encapsulatio">IPsec with GRE Encapsulation</xref></t>
                      </li>
                    </ul>
                  </li>
                  <li pn="section-toc.1-1.6.2.8.2.4">
                    <t indent="0" pn="section-toc.1-1.6.2.8.2.4.1"><xref derivedContent="6.8.4" format="counter" sectionFormat="of" target="section-6.8.4"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-via-dtls">ACP via DTLS</xref></t>
                  </li>
                  <li pn="section-toc.1-1.6.2.8.2.5">
                    <t indent="0" pn="section-toc.1-1.6.2.8.2.5.1"><xref derivedContent="6.8.5" format="counter" sectionFormat="of" target="section-6.8.5"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-secure-channel-profiles">ACP Secure Channel Profiles</xref></t>
                  </li>
                </ul>
              </li>
              <li pn="section-toc.1-1.6.2.9">
                <t indent="0" pn="section-toc.1-1.6.2.9.1"><xref derivedContent="6.9" format="counter" sectionFormat="of" target="section-6.9"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-grasp-in-the-acp">GRASP in the face ACP</xref></t>
                <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.6.2.9.2">
                  <li pn="section-toc.1-1.6.2.9.2.1">
                    <t indent="0" pn="section-toc.1-1.6.2.9.2.1.1"><xref derivedContent="6.9.1" format="counter" sectionFormat="of" target="section-6.9.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-grasp-as-a-core-service-of-">GRASP as a Core Service of operator induced misconfiguration, see <xref target="FCC"/>, for example III.B.15 on page 8: "...engineers almost immediately recognized that they had misdiagnosed the problem.  However, they were unable to resolve ACP</xref></t>
                  </li>
                  <li pn="section-toc.1-1.6.2.9.2.2">
                    <t indent="0" pn="section-toc.1-1.6.2.9.2.2.1"><xref derivedContent="6.9.2" format="counter" sectionFormat="of" target="section-6.9.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-as-the-security-and-tra">ACP as the issue by restoring the link because the network management tools required to do so remotely relied on Security and Transport Substrate for GRASP</xref></t>
                    <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.6.2.9.2.2.2">
                      <li pn="section-toc.1-1.6.2.9.2.2.2.1">
                        <t indent="0" pn="section-toc.1-1.6.2.9.2.2.2.1.1"><xref derivedContent="6.9.2.1" format="counter" sectionFormat="of" target="section-6.9.2.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-discussion">Discussion</xref></t>
                      </li>
                    </ul>
                  </li>
                </ul>
              </li>
              <li pn="section-toc.1-1.6.2.10">
                <t indent="0" pn="section-toc.1-1.6.2.10.1"><xref derivedContent="6.10" format="counter" sectionFormat="of" target="section-6.10"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-context-separation">Context Separation</xref></t>
              </li>
              <li pn="section-toc.1-1.6.2.11">
                <t indent="0" pn="section-toc.1-1.6.2.11.1"><xref derivedContent="6.11" format="counter" sectionFormat="of" target="section-6.11"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-addressing-inside-the-acp">Addressing inside the same paths they had just disabled".</t>

<t>Traditionally, physically separate, so-called out-of-band (management) networks have been used to avoid these problems ACP</xref></t>
                <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.6.2.11.2">
                  <li pn="section-toc.1-1.6.2.11.2.1">
                    <t indent="0" pn="section-toc.1-1.6.2.11.2.1.1"><xref derivedContent="6.11.1" format="counter" sectionFormat="of" target="section-6.11.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-fundamental-concepts-of-aut">Fundamental Concepts of Autonomic Addressing</xref></t>
                  </li>
                  <li pn="section-toc.1-1.6.2.11.2.2">
                    <t indent="0" pn="section-toc.1-1.6.2.11.2.2.1"><xref derivedContent="6.11.2" format="counter" sectionFormat="of" target="section-6.11.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-the-acp-addressing-base-sch">The ACP Addressing Base Scheme</xref></t>
                  </li>
                  <li pn="section-toc.1-1.6.2.11.2.3">
                    <t indent="0" pn="section-toc.1-1.6.2.11.2.3.1"><xref derivedContent="6.11.3" format="counter" sectionFormat="of" target="section-6.11.3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-zone-addressing-sub-sch">ACP Zone Addressing Sub-Scheme (ACP-Zone)</xref></t>
                  </li>
                  <li pn="section-toc.1-1.6.2.11.2.4">
                    <t indent="0" pn="section-toc.1-1.6.2.11.2.4.1"><xref derivedContent="6.11.4" format="counter" sectionFormat="of" target="section-6.11.4"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-manual-addressing-sub-s">ACP Manual Addressing Sub-Scheme (ACP-Manual)</xref></t>
                  </li>
                  <li pn="section-toc.1-1.6.2.11.2.5">
                    <t indent="0" pn="section-toc.1-1.6.2.11.2.5.1"><xref derivedContent="6.11.5" format="counter" sectionFormat="of" target="section-6.11.5"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-vlong-addressing-sub-sc">ACP Vlong Addressing Sub-Scheme (ACP-Vlong-8/ACP-Vlong-16)</xref></t>
                  </li>
                  <li pn="section-toc.1-1.6.2.11.2.6">
                    <t indent="0" pn="section-toc.1-1.6.2.11.2.6.1"><xref derivedContent="6.11.6" format="counter" sectionFormat="of" target="section-6.11.6"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-other-acp-addressing-sub-sc">Other ACP Addressing Sub-Schemes</xref></t>
                  </li>
                  <li pn="section-toc.1-1.6.2.11.2.7">
                    <t indent="0" pn="section-toc.1-1.6.2.11.2.7.1"><xref derivedContent="6.11.7" format="counter" sectionFormat="of" target="section-6.11.7"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-registrars">ACP Registrars</xref></t>
                    <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.6.2.11.2.7.2">
                      <li pn="section-toc.1-1.6.2.11.2.7.2.1">
                        <t indent="0" pn="section-toc.1-1.6.2.11.2.7.2.1.1"><xref derivedContent="6.11.7.1" format="counter" sectionFormat="of" target="section-6.11.7.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-use-of-brski-or-other-mecha">Use of BRSKI or at least to allow recovery from such problems. Worst case, personnel are sent on site to access devices through out-of-band management ports (also called craft ports, serial console, management ethernet port).  However, both options are expensive.</t>
      <t>In increasingly automated networks either centralized management systems Other Mechanisms or distributed autonomic service agents Protocols</xref></t>
                      </li>
                      <li pn="section-toc.1-1.6.2.11.2.7.2.2">
                        <t indent="0" pn="section-toc.1-1.6.2.11.2.7.2.2.1"><xref derivedContent="6.11.7.2" format="counter" sectionFormat="of" target="section-6.11.7.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-unique-address-prefix-alloc">Unique Address/Prefix Allocation</xref></t>
                      </li>
                      <li pn="section-toc.1-1.6.2.11.2.7.2.3">
                        <t indent="0" pn="section-toc.1-1.6.2.11.2.7.2.3.1"><xref derivedContent="6.11.7.3" format="counter" sectionFormat="of" target="section-6.11.7.3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-addressing-sub-scheme-polic">Addressing Sub-Scheme Policies</xref></t>
                      </li>
                      <li pn="section-toc.1-1.6.2.11.2.7.2.4">
                        <t indent="0" pn="section-toc.1-1.6.2.11.2.7.2.4.1"><xref derivedContent="6.11.7.4" format="counter" sectionFormat="of" target="section-6.11.7.4"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-address-prefix-persistence">Address/Prefix Persistence</xref></t>
                      </li>
                      <li pn="section-toc.1-1.6.2.11.2.7.2.5">
                        <t indent="0" pn="section-toc.1-1.6.2.11.2.7.2.5.1"><xref derivedContent="6.11.7.5" format="counter" sectionFormat="of" target="section-6.11.7.5"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-further-details">Further Details</xref></t>
                      </li>
                    </ul>
                  </li>
                </ul>
              </li>
              <li pn="section-toc.1-1.6.2.12">
                <t indent="0" pn="section-toc.1-1.6.2.12.1"><xref derivedContent="6.12" format="counter" sectionFormat="of" target="section-6.12"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-routing-in-the-acp">Routing in the network require a control plane which is independent ACP</xref></t>
                <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.6.2.12.2">
                  <li pn="section-toc.1-1.6.2.12.2.1">
                    <t indent="0" pn="section-toc.1-1.6.2.12.2.1.1"><xref derivedContent="6.12.1" format="counter" sectionFormat="of" target="section-6.12.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-rpl-profile">ACP RPL Profile</xref></t>
                    <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.6.2.12.2.1.2">
                      <li pn="section-toc.1-1.6.2.12.2.1.2.1">
                        <t indent="0" pn="section-toc.1-1.6.2.12.2.1.2.1.1"><xref derivedContent="6.12.1.1" format="counter" sectionFormat="of" target="section-6.12.1.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-overview">Overview</xref></t>
                        <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.6.2.12.2.1.2.1.2">
                          <li pn="section-toc.1-1.6.2.12.2.1.2.1.2.1">
                            <t indent="0" pn="section-toc.1-1.6.2.12.2.1.2.1.2.1.1"><xref derivedContent="6.12.1.1.1" format="counter" sectionFormat="of" target="section-6.12.1.1.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-single-instance">Single Instance</xref></t>
                          </li>
                          <li pn="section-toc.1-1.6.2.12.2.1.2.1.2.2">
                            <t indent="0" pn="section-toc.1-1.6.2.12.2.1.2.1.2.2.1"><xref derivedContent="6.12.1.1.2" format="counter" sectionFormat="of" target="section-6.12.1.1.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-reconvergence">Reconvergence</xref></t>
                          </li>
                        </ul>
                      </li>
                      <li pn="section-toc.1-1.6.2.12.2.1.2.2">
                        <t indent="0" pn="section-toc.1-1.6.2.12.2.1.2.2.1"><xref derivedContent="6.12.1.2" format="counter" sectionFormat="of" target="section-6.12.1.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-rpl-instances">RPL Instances</xref></t>
                      </li>
                      <li pn="section-toc.1-1.6.2.12.2.1.2.3">
                        <t indent="0" pn="section-toc.1-1.6.2.12.2.1.2.3.1"><xref derivedContent="6.12.1.3" format="counter" sectionFormat="of" target="section-6.12.1.3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-storing-vs-non-storing-mode">Storing vs. Non-Storing Mode</xref></t>
                      </li>
                      <li pn="section-toc.1-1.6.2.12.2.1.2.4">
                        <t indent="0" pn="section-toc.1-1.6.2.12.2.1.2.4.1"><xref derivedContent="6.12.1.4" format="counter" sectionFormat="of" target="section-6.12.1.4"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-dao-policy">DAO Policy</xref></t>
                      </li>
                      <li pn="section-toc.1-1.6.2.12.2.1.2.5">
                        <t indent="0" pn="section-toc.1-1.6.2.12.2.1.2.5.1"><xref derivedContent="6.12.1.5" format="counter" sectionFormat="of" target="section-6.12.1.5"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-path-metrics">Path Metrics</xref></t>
                      </li>
                      <li pn="section-toc.1-1.6.2.12.2.1.2.6">
                        <t indent="0" pn="section-toc.1-1.6.2.12.2.1.2.6.1"><xref derivedContent="6.12.1.6" format="counter" sectionFormat="of" target="section-6.12.1.6"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-objective-function">Objective Function</xref></t>
                      </li>
                      <li pn="section-toc.1-1.6.2.12.2.1.2.7">
                        <t indent="0" pn="section-toc.1-1.6.2.12.2.1.2.7.1"><xref derivedContent="6.12.1.7" format="counter" sectionFormat="of" target="section-6.12.1.7"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-dodag-repair">DODAG Repair</xref></t>
                      </li>
                      <li pn="section-toc.1-1.6.2.12.2.1.2.8">
                        <t indent="0" pn="section-toc.1-1.6.2.12.2.1.2.8.1"><xref derivedContent="6.12.1.8" format="counter" sectionFormat="of" target="section-6.12.1.8"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-multicast">Multicast</xref></t>
                      </li>
                      <li pn="section-toc.1-1.6.2.12.2.1.2.9">
                        <t indent="0" pn="section-toc.1-1.6.2.12.2.1.2.9.1"><xref derivedContent="6.12.1.9" format="counter" sectionFormat="of" target="section-6.12.1.9"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-security">Security</xref></t>
                      </li>
                      <li pn="section-toc.1-1.6.2.12.2.1.2.10">
                        <t indent="0" pn="section-toc.1-1.6.2.12.2.1.2.10.1"><xref derivedContent="6.12.1.10" format="counter" sectionFormat="of" target="section-6.12.1.10"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-p2p-communications">P2P Communications</xref></t>
                      </li>
                      <li pn="section-toc.1-1.6.2.12.2.1.2.11">
                        <t indent="0" pn="section-toc.1-1.6.2.12.2.1.2.11.1"><xref derivedContent="6.12.1.11" format="counter" sectionFormat="of" target="section-6.12.1.11"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-ipv6-address-configuration">IPv6 Address Configuration</xref></t>
                      </li>
                      <li pn="section-toc.1-1.6.2.12.2.1.2.12">
                        <t indent="0" pn="section-toc.1-1.6.2.12.2.1.2.12.1"><xref derivedContent="6.12.1.12" format="counter" sectionFormat="of" target="section-6.12.1.12"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-administrative-parameters">Administrative Parameters</xref></t>
                      </li>
                      <li pn="section-toc.1-1.6.2.12.2.1.2.13">
                        <t indent="0" pn="section-toc.1-1.6.2.12.2.1.2.13.1"><xref derivedContent="6.12.1.13" format="counter" sectionFormat="of" target="section-6.12.1.13"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-rpl-packet-information">RPL Packet Information</xref></t>
                      </li>
                      <li pn="section-toc.1-1.6.2.12.2.1.2.14">
                        <t indent="0" pn="section-toc.1-1.6.2.12.2.1.2.14.1"><xref derivedContent="6.12.1.14" format="counter" sectionFormat="of" target="section-6.12.1.14"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-unknown-destinations">Unknown Destinations</xref></t>
                      </li>
                    </ul>
                  </li>
                </ul>
              </li>
              <li pn="section-toc.1-1.6.2.13">
                <t indent="0" pn="section-toc.1-1.6.2.13.1"><xref derivedContent="6.13" format="counter" sectionFormat="of" target="section-6.13"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-general-acp-considerations">General ACP Considerations</xref></t>
                <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.6.2.13.2">
                  <li pn="section-toc.1-1.6.2.13.2.1">
                    <t indent="0" pn="section-toc.1-1.6.2.13.2.1.1"><xref derivedContent="6.13.1" format="counter" sectionFormat="of" target="section-6.13.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-performance">Performance</xref></t>
                  </li>
                  <li pn="section-toc.1-1.6.2.13.2.2">
                    <t indent="0" pn="section-toc.1-1.6.2.13.2.2.1"><xref derivedContent="6.13.2" format="counter" sectionFormat="of" target="section-6.13.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-addressing-of-secure-channe">Addressing of the configuration Secure Channels</xref></t>
                  </li>
                  <li pn="section-toc.1-1.6.2.13.2.3">
                    <t indent="0" pn="section-toc.1-1.6.2.13.2.3.1"><xref derivedContent="6.13.3" format="counter" sectionFormat="of" target="section-6.13.3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-mtu">MTU</xref></t>
                  </li>
                  <li pn="section-toc.1-1.6.2.13.2.4">
                    <t indent="0" pn="section-toc.1-1.6.2.13.2.4.1"><xref derivedContent="6.13.4" format="counter" sectionFormat="of" target="section-6.13.4"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-multiple-links-between-node">Multiple Links between Nodes</xref></t>
                  </li>
                  <li pn="section-toc.1-1.6.2.13.2.5">
                    <t indent="0" pn="section-toc.1-1.6.2.13.2.5.1"><xref derivedContent="6.13.5" format="counter" sectionFormat="of" target="section-6.13.5"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-interfaces">ACP Interfaces</xref></t>
                    <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.6.2.13.2.5.2">
                      <li pn="section-toc.1-1.6.2.13.2.5.2.1">
                        <t indent="0" pn="section-toc.1-1.6.2.13.2.5.2.1.1"><xref derivedContent="6.13.5.1" format="counter" sectionFormat="of" target="section-6.13.5.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-loopback-interfaces">ACP Loopback Interfaces</xref></t>
                      </li>
                      <li pn="section-toc.1-1.6.2.13.2.5.2.2">
                        <t indent="0" pn="section-toc.1-1.6.2.13.2.5.2.2.1"><xref derivedContent="6.13.5.2" format="counter" sectionFormat="of" target="section-6.13.5.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-virtual-interfaces">ACP Virtual Interfaces</xref></t>
                        <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.6.2.13.2.5.2.2.2">
                          <li pn="section-toc.1-1.6.2.13.2.5.2.2.2.1">
                            <t indent="0" pn="section-toc.1-1.6.2.13.2.5.2.2.2.1.1"><xref derivedContent="6.13.5.2.1" format="counter" sectionFormat="of" target="section-6.13.5.2.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-point-to-point-virtual-">ACP Point-to-Point Virtual Interfaces</xref></t>
                          </li>
                          <li pn="section-toc.1-1.6.2.13.2.5.2.2.2.2">
                            <t indent="0" pn="section-toc.1-1.6.2.13.2.5.2.2.2.2.1"><xref derivedContent="6.13.5.2.2" format="counter" sectionFormat="of" target="section-6.13.5.2.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-multi-access-virtual-in">ACP Multi-Access Virtual Interfaces</xref></t>
                          </li>
                        </ul>
                      </li>
                    </ul>
                  </li>
                </ul>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.7">
            <t indent="0" pn="section-toc.1-1.7.1"><xref derivedContent="7" format="counter" sectionFormat="of" target="section-7"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-support-on-l2-switches-">ACP Support on L2 Switches/Ports (Normative)</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.7.2">
              <li pn="section-toc.1-1.7.2.1">
                <t indent="0" pn="section-toc.1-1.7.2.1.1"><xref derivedContent="7.1" format="counter" sectionFormat="of" target="section-7.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-why-benefits-of-acp-on-l2-s">Why (Benefits of the network they manage, to avoid impacting their own operations through the configuration actions they take.</t>

      <t>This document describes a modular design ACP on L2 Switches)</xref></t>
              </li>
              <li pn="section-toc.1-1.7.2.2">
                <t indent="0" pn="section-toc.1-1.7.2.2.1"><xref derivedContent="7.2" format="counter" sectionFormat="of" target="section-7.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-how-per-l2-port-dull-grasp">How (per L2 Port DULL GRASP)</xref></t>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.8">
            <t indent="0" pn="section-toc.1-1.8.1"><xref derivedContent="8" format="counter" sectionFormat="of" target="section-8"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-support-for-non-acp-compone">Support for a self-forming, self-managing Non-ACP Components (Normative)</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.8.2">
              <li pn="section-toc.1-1.8.2.1">
                <t indent="0" pn="section-toc.1-1.8.2.1.1"><xref derivedContent="8.1" format="counter" sectionFormat="of" target="section-8.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-connect">ACP Connect</xref></t>
                <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.8.2.1.2">
                  <li pn="section-toc.1-1.8.2.1.2.1">
                    <t indent="0" pn="section-toc.1-1.8.2.1.2.1.1"><xref derivedContent="8.1.1" format="counter" sectionFormat="of" target="section-8.1.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-non-acp-controller-and-or-n">Non-ACP Controller and/or Network Management System (NMS)</xref></t>
                  </li>
                  <li pn="section-toc.1-1.8.2.1.2.2">
                    <t indent="0" pn="section-toc.1-1.8.2.1.2.2.1"><xref derivedContent="8.1.2" format="counter" sectionFormat="of" target="section-8.1.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-software-components">Software Components</xref></t>
                  </li>
                  <li pn="section-toc.1-1.8.2.1.2.3">
                    <t indent="0" pn="section-toc.1-1.8.2.1.2.3.1"><xref derivedContent="8.1.3" format="counter" sectionFormat="of" target="section-8.1.3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-autoconfiguration">Autoconfiguration</xref></t>
                  </li>
                  <li pn="section-toc.1-1.8.2.1.2.4">
                    <t indent="0" pn="section-toc.1-1.8.2.1.2.4.1"><xref derivedContent="8.1.4" format="counter" sectionFormat="of" target="section-8.1.4"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-combined-acp-and-data-plane">Combined ACP and self-protecting ACP,  which is a virtual out-of-band network designed to be as independent as possible Data Plane Interface (VRF Select)</xref></t>
                  </li>
                  <li pn="section-toc.1-1.8.2.1.2.5">
                    <t indent="0" pn="section-toc.1-1.8.2.1.2.5.1"><xref derivedContent="8.1.5" format="counter" sectionFormat="of" target="section-8.1.5"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-use-of-grasp">Use of configuration, addressing GRASP</xref></t>
                  </li>
                </ul>
              </li>
              <li pn="section-toc.1-1.8.2.2">
                <t indent="0" pn="section-toc.1-1.8.2.2.1"><xref derivedContent="8.2" format="counter" sectionFormat="of" target="section-8.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-connecting-acp-islands-over">Connecting ACP Islands over Non-ACP L3 Networks (Remote ACP Neighbors)</xref></t>
                <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.8.2.2.2">
                  <li pn="section-toc.1-1.8.2.2.2.1">
                    <t indent="0" pn="section-toc.1-1.8.2.2.2.1.1"><xref derivedContent="8.2.1" format="counter" sectionFormat="of" target="section-8.2.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-configured-remote-acp-neigh">Configured Remote ACP Neighbor</xref></t>
                  </li>
                  <li pn="section-toc.1-1.8.2.2.2.2">
                    <t indent="0" pn="section-toc.1-1.8.2.2.2.2.1"><xref derivedContent="8.2.2" format="counter" sectionFormat="of" target="section-8.2.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-tunneled-remote-acp-neighbo">Tunneled Remote ACP Neighbor</xref></t>
                  </li>
                  <li pn="section-toc.1-1.8.2.2.2.3">
                    <t indent="0" pn="section-toc.1-1.8.2.2.2.3.1"><xref derivedContent="8.2.3" format="counter" sectionFormat="of" target="section-8.2.3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-summary">Summary</xref></t>
                  </li>
                </ul>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.9">
            <t indent="0" pn="section-toc.1-1.9.1"><xref derivedContent="9" format="counter" sectionFormat="of" target="section-9"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-operations-informative">ACP Operations (Informative)</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.9.2">
              <li pn="section-toc.1-1.9.2.1">
                <t indent="0" pn="section-toc.1-1.9.2.1.1"><xref derivedContent="9.1" format="counter" sectionFormat="of" target="section-9.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-and-brski-diagnostics">ACP (and BRSKI) Diagnostics</xref></t>
                <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.9.2.1.2">
                  <li pn="section-toc.1-1.9.2.1.2.1">
                    <t indent="0" pn="section-toc.1-1.9.2.1.2.1.1"><xref derivedContent="9.1.1" format="counter" sectionFormat="of" target="section-9.1.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-secure-channel-peer-diagnos">Secure Channel Peer Diagnostics</xref></t>
                  </li>
                </ul>
              </li>
              <li pn="section-toc.1-1.9.2.2">
                <t indent="0" pn="section-toc.1-1.9.2.2.1"><xref derivedContent="9.2" format="counter" sectionFormat="of" target="section-9.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-registrars-2">ACP Registrars</xref></t>
                <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.9.2.2.2">
                  <li pn="section-toc.1-1.9.2.2.2.1">
                    <t indent="0" pn="section-toc.1-1.9.2.2.2.1.1"><xref derivedContent="9.2.1" format="counter" sectionFormat="of" target="section-9.2.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-registrar-interactions">Registrar Interactions</xref></t>
                  </li>
                  <li pn="section-toc.1-1.9.2.2.2.2">
                    <t indent="0" pn="section-toc.1-1.9.2.2.2.2.1"><xref derivedContent="9.2.2" format="counter" sectionFormat="of" target="section-9.2.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-registrar-parameters">Registrar Parameters</xref></t>
                  </li>
                  <li pn="section-toc.1-1.9.2.2.2.3">
                    <t indent="0" pn="section-toc.1-1.9.2.2.2.3.1"><xref derivedContent="9.2.3" format="counter" sectionFormat="of" target="section-9.2.3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-certificate-renewal-and-lim">Certificate Renewal and routing to avoid Limitations</xref></t>
                  </li>
                  <li pn="section-toc.1-1.9.2.2.2.4">
                    <t indent="0" pn="section-toc.1-1.9.2.2.2.4.1"><xref derivedContent="9.2.4" format="counter" sectionFormat="of" target="section-9.2.4"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-registrars-with-sub-ca">ACP Registrars with Sub-CA</xref></t>
                  </li>
                  <li pn="section-toc.1-1.9.2.2.2.5">
                    <t indent="0" pn="section-toc.1-1.9.2.2.2.5.1"><xref derivedContent="9.2.5" format="counter" sectionFormat="of" target="section-9.2.5"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-centralized-policy-control">Centralized Policy Control</xref></t>
                  </li>
                </ul>
              </li>
              <li pn="section-toc.1-1.9.2.3">
                <t indent="0" pn="section-toc.1-1.9.2.3.1"><xref derivedContent="9.3" format="counter" sectionFormat="of" target="section-9.3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-enabling-and-disabling-the-">Enabling and Disabling the self-dependency problems of current IP  networks while still operating in-band on ACP and/or the same physical network that it is controlling ANI</xref></t>
                <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.9.2.3.2">
                  <li pn="section-toc.1-1.9.2.3.2.1">
                    <t indent="0" pn="section-toc.1-1.9.2.3.2.1.1"><xref derivedContent="9.3.1" format="counter" sectionFormat="of" target="section-9.3.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-filtering-for-non-acp-ani-p">Filtering for Non-ACP/ANI Packets</xref></t>
                  </li>
                  <li pn="section-toc.1-1.9.2.3.2.2">
                    <t indent="0" pn="section-toc.1-1.9.2.3.2.2.1"><xref derivedContent="9.3.2" format="counter" sectionFormat="of" target="section-9.3.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-admin-down-state">"admin down" State</xref></t>
                    <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.9.2.3.2.2.2">
                      <li pn="section-toc.1-1.9.2.3.2.2.2.1">
                        <t indent="0" pn="section-toc.1-1.9.2.3.2.2.2.1.1"><xref derivedContent="9.3.2.1" format="counter" sectionFormat="of" target="section-9.3.2.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-security-2">Security</xref></t>
                      </li>
                      <li pn="section-toc.1-1.9.2.3.2.2.2.2">
                        <t indent="0" pn="section-toc.1-1.9.2.3.2.2.2.2.1"><xref derivedContent="9.3.2.2" format="counter" sectionFormat="of" target="section-9.3.2.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-fast-state-propagation-and-">Fast State Propagation and managing. The Diagnostics</xref></t>
                      </li>
                      <li pn="section-toc.1-1.9.2.3.2.2.2.3">
                        <t indent="0" pn="section-toc.1-1.9.2.3.2.2.2.3.1"><xref derivedContent="9.3.2.3" format="counter" sectionFormat="of" target="section-9.3.2.3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-low-level-link-diagnostics">Low-Level Link Diagnostics</xref></t>
                      </li>
                      <li pn="section-toc.1-1.9.2.3.2.2.2.4">
                        <t indent="0" pn="section-toc.1-1.9.2.3.2.2.2.4.1"><xref derivedContent="9.3.2.4" format="counter" sectionFormat="of" target="section-9.3.2.4"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-power-consumption-issues">Power Consumption Issues</xref></t>
                      </li>
                    </ul>
                  </li>
                  <li pn="section-toc.1-1.9.2.3.2.3">
                    <t indent="0" pn="section-toc.1-1.9.2.3.2.3.1"><xref derivedContent="9.3.3" format="counter" sectionFormat="of" target="section-9.3.3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-enabling-interface-level-ac">Enabling Interface-Level ACP design is therefore intended and ANI</xref></t>
                  </li>
                  <li pn="section-toc.1-1.9.2.3.2.4">
                    <t indent="0" pn="section-toc.1-1.9.2.3.2.4.1"><xref derivedContent="9.3.4" format="counter" sectionFormat="of" target="section-9.3.4"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-which-interfaces-to-auto-en">Which Interfaces to combine as well as possible Auto-Enable?</xref></t>
                  </li>
                  <li pn="section-toc.1-1.9.2.3.2.5">
                    <t indent="0" pn="section-toc.1-1.9.2.3.2.5.1"><xref derivedContent="9.3.5" format="counter" sectionFormat="of" target="section-9.3.5"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-enabling-node-level-acp-and">Enabling Node-Level ACP and ANI</xref></t>
                    <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.9.2.3.2.5.2">
                      <li pn="section-toc.1-1.9.2.3.2.5.2.1">
                        <t indent="0" pn="section-toc.1-1.9.2.3.2.5.2.1.1"><xref derivedContent="9.3.5.1" format="counter" sectionFormat="of" target="section-9.3.5.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-brownfield-nodes">Brownfield Nodes</xref></t>
                      </li>
                      <li pn="section-toc.1-1.9.2.3.2.5.2.2">
                        <t indent="0" pn="section-toc.1-1.9.2.3.2.5.2.2.1"><xref derivedContent="9.3.5.2" format="counter" sectionFormat="of" target="section-9.3.5.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-greenfield-nodes">Greenfield Nodes</xref></t>
                      </li>
                    </ul>
                  </li>
                  <li pn="section-toc.1-1.9.2.3.2.6">
                    <t indent="0" pn="section-toc.1-1.9.2.3.2.6.1"><xref derivedContent="9.3.6" format="counter" sectionFormat="of" target="section-9.3.6"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-undoing-ani-acp-enable">Undoing "ANI/ACP enable"</xref></t>
                  </li>
                  <li pn="section-toc.1-1.9.2.3.2.7">
                    <t indent="0" pn="section-toc.1-1.9.2.3.2.7.1"><xref derivedContent="9.3.7" format="counter" sectionFormat="of" target="section-9.3.7"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-summary-2">Summary</xref></t>
                  </li>
                </ul>
              </li>
              <li pn="section-toc.1-1.9.2.4">
                <t indent="0" pn="section-toc.1-1.9.2.4.1"><xref derivedContent="9.4" format="counter" sectionFormat="of" target="section-9.4"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-partial-or-incremental-adop">Partial or Incremental Adoption</xref></t>
              </li>
              <li pn="section-toc.1-1.9.2.5">
                <t indent="0" pn="section-toc.1-1.9.2.5.1"><xref derivedContent="9.5" format="counter" sectionFormat="of" target="section-9.5"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-configuration-and-the-acp-s">Configuration and the resilience of out-of-band management networks with ACP (Summary)</xref></t>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.10">
            <t indent="0" pn="section-toc.1-1.10.1"><xref derivedContent="10" format="counter" sectionFormat="of" target="section-10"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-summary-benefits-informativ">Summary: Benefits (Informative)</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.10.2">
              <li pn="section-toc.1-1.10.2.1">
                <t indent="0" pn="section-toc.1-1.10.2.1.1"><xref derivedContent="10.1" format="counter" sectionFormat="of" target="section-10.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-self-healing-properties">Self-Healing Properties</xref></t>
              </li>
              <li pn="section-toc.1-1.10.2.2">
                <t indent="0" pn="section-toc.1-1.10.2.2.1"><xref derivedContent="10.2" format="counter" sectionFormat="of" target="section-10.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-self-protection-properties">Self-Protection Properties</xref></t>
                <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.10.2.2.2">
                  <li pn="section-toc.1-1.10.2.2.2.1">
                    <t indent="0" pn="section-toc.1-1.10.2.2.2.1.1"><xref derivedContent="10.2.1" format="counter" sectionFormat="of" target="section-10.2.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-from-the-outside">From the low-cost Outside</xref></t>
                  </li>
                  <li pn="section-toc.1-1.10.2.2.2.2">
                    <t indent="0" pn="section-toc.1-1.10.2.2.2.2.1"><xref derivedContent="10.2.2" format="counter" sectionFormat="of" target="section-10.2.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-from-the-inside">From the Inside</xref></t>
                  </li>
                </ul>
              </li>
              <li pn="section-toc.1-1.10.2.3">
                <t indent="0" pn="section-toc.1-1.10.2.3.1"><xref derivedContent="10.3" format="counter" sectionFormat="of" target="section-10.3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-the-administrator-view">The Administrator View</xref></t>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.11">
            <t indent="0" pn="section-toc.1-1.11.1"><xref derivedContent="11" format="counter" sectionFormat="of" target="section-11"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-security-considerations">Security Considerations</xref></t>
          </li>
          <li pn="section-toc.1-1.12">
            <t indent="0" pn="section-toc.1-1.12.1"><xref derivedContent="12" format="counter" sectionFormat="of" target="section-12"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-iana-considerations">IANA Considerations</xref></t>
          </li>
          <li pn="section-toc.1-1.13">
            <t indent="0" pn="section-toc.1-1.13.1"><xref derivedContent="13" format="counter" sectionFormat="of" target="section-13"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-references">References</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.13.2">
              <li pn="section-toc.1-1.13.2.1">
                <t indent="0" pn="section-toc.1-1.13.2.1.1"><xref derivedContent="13.1" format="counter" sectionFormat="of" target="section-13.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-normative-references">Normative References</xref></t>
              </li>
              <li pn="section-toc.1-1.13.2.2">
                <t indent="0" pn="section-toc.1-1.13.2.2.1"><xref derivedContent="13.2" format="counter" sectionFormat="of" target="section-13.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-informative-references">Informative References</xref></t>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.14">
            <t indent="0" pn="section-toc.1-1.14.1"><xref derivedContent="Appendix A" format="default" sectionFormat="of" target="section-appendix.a"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-background-and-future-infor">Background and Future (Informative)</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.14.2">
              <li pn="section-toc.1-1.14.2.1">
                <t indent="0" pn="section-toc.1-1.14.2.1.1"><xref derivedContent="A.1" format="counter" sectionFormat="of" target="section-a.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-address-space-schemes">ACP Address Space Schemes</xref></t>
              </li>
              <li pn="section-toc.1-1.14.2.2">
                <t indent="0" pn="section-toc.1-1.14.2.2.1"><xref derivedContent="A.2" format="counter" sectionFormat="of" target="section-a.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-brski-bootstrap-ani">BRSKI Bootstrap (ANI)</xref></t>
              </li>
              <li pn="section-toc.1-1.14.2.3">
                <t indent="0" pn="section-toc.1-1.14.2.3.1"><xref derivedContent="A.3" format="counter" sectionFormat="of" target="section-a.3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-neighbor-discovery-prot">ACP Neighbor Discovery Protocol Selection</xref></t>
                <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.14.2.3.2">
                  <li pn="section-toc.1-1.14.2.3.2.1">
                    <t indent="0" pn="section-toc.1-1.14.2.3.2.1.1"><xref derivedContent="A.3.1" format="counter" sectionFormat="of" target="section-a.3.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-lldp">LLDP</xref></t>
                  </li>
                  <li pn="section-toc.1-1.14.2.3.2.2">
                    <t indent="0" pn="section-toc.1-1.14.2.3.2.2.1"><xref derivedContent="A.3.2" format="counter" sectionFormat="of" target="section-a.3.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-mdns-and-l2-support">mDNS and L2 Support</xref></t>
                  </li>
                  <li pn="section-toc.1-1.14.2.3.2.3">
                    <t indent="0" pn="section-toc.1-1.14.2.3.2.3.1"><xref derivedContent="A.3.3" format="counter" sectionFormat="of" target="section-a.3.3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-why-dull-grasp">Why DULL GRASP?</xref></t>
                  </li>
                </ul>
              </li>
              <li pn="section-toc.1-1.14.2.4">
                <t indent="0" pn="section-toc.1-1.14.2.4.1"><xref derivedContent="A.4" format="counter" sectionFormat="of" target="section-a.4"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-choice-of-routing-protocol-">Choice of traditional IP in-band network management.  The details how this is achieved are described in <xref target="self-creation" format="default"/>.</t>
      <t>In a fully autonomic network node without legacy control or management functions/protocols, Routing Protocol (RPL)</xref></t>
              </li>
              <li pn="section-toc.1-1.14.2.5">
                <t indent="0" pn="section-toc.1-1.14.2.5.1"><xref derivedContent="A.5" format="counter" sectionFormat="of" target="section-a.5"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-information-distributio">ACP Information Distribution and Multicast</xref></t>
              </li>
              <li pn="section-toc.1-1.14.2.6">
                <t indent="0" pn="section-toc.1-1.14.2.6.1"><xref derivedContent="A.6" format="counter" sectionFormat="of" target="section-a.6"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-cas-domains-and-routing-sub">CAs, Domains, and Routing Subdomains</xref></t>
              </li>
              <li pn="section-toc.1-1.14.2.7">
                <t indent="0" pn="section-toc.1-1.14.2.7.1"><xref derivedContent="A.7" format="counter" sectionFormat="of" target="section-a.7"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-intent-for-the-acp">Intent for the Data-Plane would be ACP</xref></t>
              </li>
              <li pn="section-toc.1-1.14.2.8">
                <t indent="0" pn="section-toc.1-1.14.2.8.1"><xref derivedContent="A.8" format="counter" sectionFormat="of" target="section-a.8"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-adopting-acp-concepts-for-o">Adopting ACP Concepts for example just a forwarding plane Other Environments</xref></t>
              </li>
              <li pn="section-toc.1-1.14.2.9">
                <t indent="0" pn="section-toc.1-1.14.2.9.1"><xref derivedContent="A.9" format="counter" sectionFormat="of" target="section-a.9"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-further-future-options">Further (Future) Options</xref></t>
                <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.14.2.9.2">
                  <li pn="section-toc.1-1.14.2.9.2.1">
                    <t indent="0" pn="section-toc.1-1.14.2.9.2.1.1"><xref derivedContent="A.9.1" format="counter" sectionFormat="of" target="section-a.9.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-auto-aggregation-of-routes">Auto-Aggregation of Routes</xref></t>
                  </li>
                  <li pn="section-toc.1-1.14.2.9.2.2">
                    <t indent="0" pn="section-toc.1-1.14.2.9.2.2.1"><xref derivedContent="A.9.2" format="counter" sectionFormat="of" target="section-a.9.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-more-options-for-avoiding-i">More Options for "Data" Avoiding IPv6 packets, aka: packets other than the control Data Plane Dependencies</xref></t>
                  </li>
                  <li pn="section-toc.1-1.14.2.9.2.3">
                    <t indent="0" pn="section-toc.1-1.14.2.9.2.3.1"><xref derivedContent="A.9.3" format="counter" sectionFormat="of" target="section-a.9.3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acp-apis-and-operational-mo">ACP APIs and  management plane packets that are forwarded by the ACP itself.  In such networks/nodes, there would be no non-autonomous control or non-autonomous management plane.</t>
      <t>Routing protocols for example would be built inside the Operational Models (YANG)</xref></t>
                  </li>
                  <li pn="section-toc.1-1.14.2.9.2.4">
                    <t indent="0" pn="section-toc.1-1.14.2.9.2.4.1"><xref derivedContent="A.9.4" format="counter" sectionFormat="of" target="section-a.9.4"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-rpl-enhancements">RPL Enhancements</xref></t>
                  </li>
                  <li pn="section-toc.1-1.14.2.9.2.5">
                    <t indent="0" pn="section-toc.1-1.14.2.9.2.5.1"><xref derivedContent="A.9.5" format="counter" sectionFormat="of" target="section-a.9.5"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-role-assignments">Role Assignments</xref></t>
                  </li>
                  <li pn="section-toc.1-1.14.2.9.2.6">
                    <t indent="0" pn="section-toc.1-1.14.2.9.2.6.1"><xref derivedContent="A.9.6" format="counter" sectionFormat="of" target="section-a.9.6"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-autonomic-l3-transit">Autonomic L3 Transit</xref></t>
                  </li>
                  <li pn="section-toc.1-1.14.2.9.2.7">
                    <t indent="0" pn="section-toc.1-1.14.2.9.2.7.1"><xref derivedContent="A.9.7" format="counter" sectionFormat="of" target="section-a.9.7"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-diagnostics">Diagnostics</xref></t>
                  </li>
                  <li pn="section-toc.1-1.14.2.9.2.8">
                    <t indent="0" pn="section-toc.1-1.14.2.9.2.8.1"><xref derivedContent="A.9.8" format="counter" sectionFormat="of" target="section-a.9.8"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-avoiding-and-dealing-with-c">Avoiding and Dealing with Compromised ACP as so-called autonomous Nodes</xref></t>
                  </li>
                  <li pn="section-toc.1-1.14.2.9.2.9">
                    <t indent="0" pn="section-toc.1-1.14.2.9.2.9.1"><xref derivedContent="A.9.9" format="counter" sectionFormat="of" target="section-a.9.9"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-detecting-acp-secure-channe">Detecting ACP Secure Channel Downgrade Attacks</xref></t>
                  </li>
                </ul>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.15">
            <t indent="0" pn="section-toc.1-1.15.1"><xref derivedContent="" format="none" sectionFormat="of" target="section-appendix.b"/><xref derivedContent="" format="title" sectionFormat="of" target="name-acknowledgements">Acknowledgements</xref></t>
          </li>
          <li pn="section-toc.1-1.16">
            <t indent="0" pn="section-toc.1-1.16.1"><xref derivedContent="" format="none" sectionFormat="of" target="section-appendix.c"/><xref derivedContent="" format="title" sectionFormat="of" target="name-contributors">Contributors</xref></t>
          </li>
          <li pn="section-toc.1-1.17">
            <t indent="0" pn="section-toc.1-1.17.1"><xref derivedContent="" format="none" sectionFormat="of" target="section-appendix.d"/><xref derivedContent="" format="title" sectionFormat="of" target="name-authors-addresses">Authors' Addresses</xref></t>
          </li>
        </ul>
      </section>
    </toc>
  </front>
  <middle>
    <section anchor="intro" numbered="true" toc="include" removeInRFC="false" pn="section-1">
      <name slugifiedName="name-introduction-informative">Introduction (Informative)</name>
      <t indent="0" pn="section-1-1">Autonomic Networking is a concept of self-management: autonomic functions via autonomous service agents, leveraging self-configure, and negotiate parameters and settings across the ACP's functions instead network. "<xref target="RFC7575" format="title" sectionFormat="of" derivedContent="Autonomic Networking: Definitions and Design Goals"/>" <xref target="RFC7575" format="default" sectionFormat="of" derivedContent="RFC7575"/> defines the fundamental ideas and design goals of implementing them separately Autonomic Networking.  A gap analysis of Autonomic Networking is given in "<xref target="RFC7576" format="title" sectionFormat="of" derivedContent="General Gap Analysis for each protocol: discovery, automatically established authenticated Autonomic Networking"/>" <xref target="RFC7576" format="default" sectionFormat="of" derivedContent="RFC7576"/>.  The reference architecture for Autonomic Networking in the IETF is specified in the document "<xref target="RFC8993" format="title" sectionFormat="of" derivedContent="A Reference Model for Autonomic Networking"/>" <xref target="RFC8993" format="default" sectionFormat="of" derivedContent="RFC8993"/>.</t>
      <t indent="0" pn="section-1-2">Autonomic functions need an autonomically built communications
      infrastructure.  This infrastructure needs to be secure, resilient, and encrypted local
      reusable by all autonomic functions.  <xref target="RFC7575" sectionFormat="of" section="5" format="default" derivedLink="https://rfc-editor.org/rfc/rfc7575#section-5" derivedContent="RFC7575"/> introduces that infrastructure and distant peer connectivity calls it the Autonomic Control Plane (ACP).  More descriptively, it could be called the "Autonomic communications infrastructure for control and management traffic, OAM and common control/management protocol session control".  For naming consistency with that prior document, this document continues to use the name ACP.</t>
      <t indent="0" pn="section-1-3">Today, the OAM and presentation functions.</t>
      <t>When ACP functionality control plane of IP networks is added to nodes that have non-autonomous what is typically called in-band management plane and/or signaling: its management and control plane functions (henceforth called non-autonomous nodes), protocol traffic depends on the ACP instead is best abstracted as a special Virtual Routing routing and Forwarding (VRF) instance (or virtual router) forwarding tables, security, policy, QoS, and potentially other configuration that first has to be established through the complete pre-existing non-autonomous very same management and/or and control plane is considered protocols. Misconfigurations, including unexpected side effects or mutual  dependencies, can disrupt OAM and control operations and especially disrupt remote management access to be part of the Data-Plane affected node itself and potentially disrupt access to avoid introduction a much larger number of more complex, new terminology only nodes for this case.</t>
      <t>Like which the forwarding plane affected node is on the network path.</t>
      <t indent="0" pn="section-1-4">For an example of in-band management failing in the face of operator-induced misconfiguration, see <xref target="FCC" format="default" sectionFormat="of" derivedContent="FCC"/>, for "Data" packets, example, Section III.B.15 on page 8:</t>
      <blockquote pn="section-1-5">...engineers almost immediately recognized that they had misdiagnosed the non-autonomous control and problem.  However, they were unable to resolve the issue by restoring the link because the network management plane functions can then be managed/used via tools required to do so remotely relied on the ACP. This terminology is consistent with pre-existing documents same paths they had just disabled.</blockquote>
      <t indent="0" pn="section-1-6">Traditionally, physically separate, so-called out-of-band (management) networks have been used to avoid these problems or at least to allow recovery from such as <xref target="RFC8368" format="default"/>.</t>
      <t>In problems. In the worst-case scenario, personnel are sent on site to access devices through out-of-band management ports (also called craft ports, serial consoles, or management Ethernet ports).  However, both instances (autonomous options are expensive.</t>
      <t indent="0" pn="section-1-7">In increasingly automated networks, both centralized management systems
and non-autonomous nodes), distributed autonomic service agents in the ACP is built such network require a control plane that it is operating in the absence independent of the Data-Plane, and in the case configuration of existing non-autonomous (management, control) components in the Data-Plane also in the presence of any (mis-)configuration thereof.</t>
      <t>The Autonomic Control Plane serves several purposes at network they manage, to avoid impacting their own operations through the same time: configuration actions they take.</t>
      <t indent="0" pn="section-1-8">This document describes a modular design for a self-forming, self-managing, and self-protecting ACP,  which is a virtual out-of-band network designed to be as independent as possible of configuration, addressing, and routing to avoid the self-dependency problems of current IP  networks while still operating in-band on the same physical network that it is controlling and managing. The ACP design is therefore intended to combine as well as possible the resilience of out-of-band management networks with the low cost of traditional IP in-band network management.  The details of how this is achieved are described in <xref target="self-creation" format="default" sectionFormat="of" derivedContent="Section 6"/>.</t>
      <t indent="0" pn="section-1-9">In a fully Autonomic Network without legacy control or management functions and/or protocols, the data plane would be just a forwarding plane for "data" IPv6 packets, which are packets other than those control and  management plane packets forwarded by the ACP itself.  In such a network, there would be no non-autonomous control of nodes nor a non-autonomous management plane.</t>
      <t indent="0" pn="section-1-10">Routing protocols would be built inside the ACP as autonomous functions via autonomous service agents, leveraging the following ACP functions instead of implementing them separately for each protocol: discovery; automatically established, authenticated, and encrypted local and distant peer connectivity for control and management traffic; and common session and presentation functions of the control and management protocol.</t>
      <t indent="0" pn="section-1-11">When ACP functionality is added to nodes that do not have autonomous management plane and/or control plane functions (henceforth called non-autonomous nodes), the ACP instead is best abstracted as a special Virtual Routing and Forwarding (VRF) instance (or virtual router), and the complete, preexisting, non-autonomous management and/or control plane is considered to be part of the data plane to avoid introducing more complex terminology only for this case.</t>
      <t indent="0" pn="section-1-12">Like the forwarding plane for "data" packets, the non-autonomous control and management plane functions can then be managed and/or used via the ACP. This terminology is consistent with preexisting documents such as "<xref target="RFC8368" format="title" sectionFormat="of" derivedContent="Using an Autonomic Control Plane for Stable Connectivity of Network Operations, Administration, and Maintenance (OAM)"/>" <xref target="RFC8368" format="default" sectionFormat="of" derivedContent="RFC8368"/>.</t>
      <t indent="0" pn="section-1-13">In both autonomous and non-autonomous instances, the ACP is built such that it operates in the absence of the data plane.
The ACP also operates in the presence of any (mis)configured non-autonomous management and/or control components in the data plane.</t>
      <t indent="0" pn="section-1-14">The ACP serves several purposes simultaneously:
      </t>
      <ol type="1" spacing="compact">
        <li>Autonomic spacing="normal" indent="adaptive" start="1" pn="section-1-15">
        <li pn="section-1-15.1" derivedCounter="1.">Autonomic functions communicate over the ACP.  The ACP therefore directly supports Autonomic Networking functions, as described in <xref target="I-D.ietf-anima-reference-model" format="default"/>. target="RFC8993" format="default" sectionFormat="of" derivedContent="RFC8993"/>.  For example, Generic GRASP ("<xref target="RFC8990" format="title" sectionFormat="of" derivedContent="GeneRic Autonomic Signaling Protocol (GRASP - (GRASP)"/>" <xref target="I-D.ietf-anima-grasp" format="default"/>) target="RFC8990" format="default" sectionFormat="of" derivedContent="RFC8990"/>) runs securely inside the ACP and depends on the ACP as its "security and transport substrate".</li>
        <li>A
        <li pn="section-1-15.2" derivedCounter="2.">A controller or network management system can use it ACP to securely bootstrap network devices in remote locations, even if the (Data-Plane) (data plane) network in between is not yet configured; no Data-Plane dependent bootstrap configuration that is dependent on the data plane is required.  An example of such a secure bootstrap process is described in "<xref target="RFC8995" format="title" sectionFormat="of" derivedContent="Bootstrapping Remote Secure Key Infrastructure (BRSKI)"/>" <xref target="I-D.ietf-anima-bootstrapping-keyinfra" format="default"/>.</li>
        <li>An target="RFC8995" format="default" sectionFormat="of" derivedContent="RFC8995"/>.</li>
        <li pn="section-1-15.3" derivedCounter="3.">An operator can use it ACP to access remote devices using protocols such as Secure SHell (SSH) or Network Configuration Protocol (NETCONF) running across the ACP, (NETCONF), even if the network is misconfigured or not configured.</li> unconfigured.</li>
      </ol>
      <t>This
      <t indent="0" pn="section-1-16">This document describes these purposes as use cases for the ACP in <xref target="usage" format="default"/>, format="default" sectionFormat="of" derivedContent="Section 3"/>, and it defines the requirements in <xref target="requirements" format="default"/>. format="default" sectionFormat="of" derivedContent="Section 4"/>. <xref target="overview" format="default"/> format="default" sectionFormat="of" derivedContent="Section 5"/> gives an overview of how the ACP is constructed.</t>
      <t>The
      <t indent="0" pn="section-1-17">The normative part of this document starts with <xref target="self-creation" format="default"/>, format="default" sectionFormat="of" derivedContent="Section 6"/>, where the ACP is specified. <xref target="acp-l2-switches" format="default"/> format="default" sectionFormat="of" derivedContent="Section 7"/> explains how to support ACP on L2 Layer 2 (L2) switches (normative). <xref target="workarounds" format="default"/> format="default" sectionFormat="of" derivedContent="Section 8"/> explains how non-ACP nodes and networks can be integrated (normative).</t>
      <t>The
      <t indent="0" pn="section-1-18">The remaining sections are non-normative: non-normative. <xref target="benefit" format="default"/> format="default" sectionFormat="of" derivedContent="Section 10"/> reviews the benefits of the ACP (after all the details have been defined), defined). <xref target="operational" format="default"/> format="default" sectionFormat="of" derivedContent="Section 9"/> provides operational recommendations, recommendations. <xref target="further" format="default"/> format="default" sectionFormat="of" derivedContent="Appendix A"/>
   provides additional explanations background and describes additional details or future standard or proprietary possible
   extensions that were considered not to be appropriate applicable for standardization in this document specification but were
   considered important to document.
There are no dependencies against on <xref target="further" format="default"/> format="default" sectionFormat="of" derivedContent="Appendix A"/> in order to build a complete working and interoperable
ACP according to this document.</t>
      <t>The
      <t indent="0" pn="section-1-19">The ACP provides secure IPv6 connectivity, therefore connectivity; therefore, it can be used not only as the for secure connectivity not only for self-management as required for the ACP in <xref target="RFC7575" format="default"/>, format="default" sectionFormat="of" derivedContent="RFC7575"/> but it can also be used as the secure connectivity for traditional (centralized) management. The ACP can be implemented and operated without any other components of autonomic networks, Autonomic Networks, except for the GRASP protocol. GRASP. ACP relies on per-link DULL Discovery Unsolicited Link-Local (DULL) GRASP (see <xref target="discovery-grasp" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 6.4"/>) to autodiscover auto-discover ACP neighbors, neighbors and includes the ACP GRASP instance to provide service discovery for clients of the ACP (see <xref target="GRASP" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 6.9"/>), including for its own maintenance of ACP certificates.</t>
      <t>The
      <t indent="0" pn="section-1-20">The document <xref target="RFC8368" format="default">"Using Autonomic Control Plane for Stable Connectivity of Network OAM"</xref> format="default" sectionFormat="of" derivedContent="RFC8368"/> describes how the ACP alone can be used alone to provide secure and stable connectivity for autonomic and non-autonomic OAM applications, specifically for the case of current non-autonomic networks/nodes. networks and/or nodes. That document also explains how existing management solutions can leverage the ACP in parallel with traditional management models, when to use the ACP ACP, and how to integrate with potentially IPv4 only IPv4-only OAM backends.</t>
      <t>Combining
      <t indent="0" pn="section-1-21">Combining ACP with Bootstrapping Remote Secure Key Infrastructures (BRSKI), see Infrastructure (BRSKI) (see <xref target="I-D.ietf-anima-bootstrapping-keyinfra" format="default"/>) target="RFC8995" format="default" sectionFormat="of" derivedContent="RFC8995"/>) results in the "Autonomic Network Infrastructure" (ANI) as defined in <xref target="I-D.ietf-anima-reference-model" format="default"/>, target="RFC8993" format="default" sectionFormat="of" derivedContent="RFC8993"/>, which provides autonomic connectivity (from ACP) with secure zero-touch (automated) bootstrap from BRSKI.  The ANI itself does not constitute an Autonomic Network, but it allows the building of more or less autonomic networks Autonomic Networks on top of it - it, using either centralized, Software Defined Networking- (SDN-)style centralized automation in SDN style (see "<xref target="RFC7426" format="title" sectionFormat="of" derivedContent="Software-Defined Networking (SDN): Layers and Architecture Terminology"/>" <xref target="RFC7426" format="default"/>) automation format="default" sectionFormat="of" derivedContent="RFC7426"/>) or distributed automation via Autonomic Service Agents (ASA) / and/or Autonomic Functions (AF) - (AF), or a mixture of both.  See <xref target="I-D.ietf-anima-reference-model" format="default"/> target="RFC8993" format="default" sectionFormat="of" derivedContent="RFC8993"/> for more information.</t>
      <section anchor="applicability" numbered="true" toc="default">
        <name>Applicability toc="include" removeInRFC="false" pn="section-1.1">
        <name slugifiedName="name-applicability-and-scope">Applicability and Scope</name>
        <t>Please
        <t indent="0" pn="section-1.1-1">Please see the following Terminology section (<xref target="terminology" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 2"/>) for explanations of terms used in this section.</t>
        <t>The
        <t indent="0" pn="section-1.1-2">The design of the ACP as defined in this document is considered to
	be applicable to all types of "professionally managed" networks:
	Service Provider, Local Area Network (LAN), Metro(politan networks), Metropolitan Area Network (MAN/Metro),
	Wide Area Network (WAN), Enterprise Information Technology (IT) and
	<xref target="ot" format="none">-&gt;"Operational Technology"</xref> format="none" sectionFormat="of" derivedContent="">Operational Technology</xref> (OT) networks. The ACP can operate equally on layer Layer 3 (L3) equipment and on layer 2 L2 equipment such as bridges (see <xref target="acp-l2-switches" format="default"/>). format="default" sectionFormat="of" derivedContent="Section 7"/>). The hop-by-hop authentication, integrity-protection integrity protection, and confidentiality mechanism used by the ACP is defined to be negotiable, therefore negotiable; therefore, it can be extended  to environments with different protocol preferences. The minimum implementation requirements in this document attempt to achieve maximum interoperability by requiring support for multiple options depending on the type of device: IPsec, see <xref IPsec (see "<xref target="RFC4301" format="default"/>, format="title" sectionFormat="of" derivedContent="Security Architecture for the Internet Protocol"/>" <xref target="RFC4301" format="default" sectionFormat="of" derivedContent="RFC4301"/>) and Datagram Transport Layer Security (DTLS, see <xref target="DTLS" format="default"/>).</t>
        <t>The format="default" sectionFormat="of" derivedContent="Section 6.8.4"/>).</t>
        <t indent="0" pn="section-1.1-3">The implementation footprint of the ACP consists of Public Key Infrastructure (PKI) code for the ACP certificate including "Enrollment EST (see "<xref target="RFC7030" format="title" sectionFormat="of" derivedContent="Enrollment over Secure Transport (EST, see Transport"/>" <xref target="RFC7030" format="default"/>), the GRASP protocol, format="default" sectionFormat="of" derivedContent="RFC7030"/>), GRASP, UDP, TCP TCP, and Transport Layer Security (TLS, see <xref target="tls" format="default"/>), for format="default" sectionFormat="of" derivedContent="Section 6.1"/>). For more information regarding the security and reliability of GRASP and for EST, the ACP secure channel protocol used (such as IPsec or DTLS), and an instance of IPv6 packet forwarding and routing via the RPL, see "<xref target="RFC6550" format="title" sectionFormat="of" derivedContent="RPL: IPv6 Routing Protocol for Low-power Low-Power and Lossy Networks (RPL), see Networks"/>" <xref target="RFC6550" format="default"/>, that format="default" sectionFormat="of" derivedContent="RFC6550"/>, which is separate from routing and forwarding for the Data-Plane data plane (user traffic).</t>
        <t>The
        <t indent="0" pn="section-1.1-4">The ACP uses only IPv6 to avoid the complexity of dual-stack (both IPv6 and IPv4) ACP operations (IPv6/IPv4). operations. Nevertheless, it can be integrated without any changes be integrated into even to otherwise IPv4-only network devices. The Data-Plane data plane itself would not need to change change, and it could continue to be IPv4 only. For such IPv4-only devices, the IPv6 protocol itself would be additional implementation footprint that is only required for the ACP.</t>
        <t>The
        <t indent="0" pn="section-1.1-5">The protocol choices of the ACP are primarily based on wide use and support in networks and devices, well understood well-understood security properties properties, and required scalability. The ACP design is an attempt to produce the lowest risk combination of existing technologies and protocols to build a widely applicable applicable, operational network management solution.</t>
        <t>RPL
        <t indent="0" pn="section-1.1-6">RPL was chosen because it requires a smaller routing table footprint in large networks compared to other routing protocols with an autonomically configured single area. The deployment experience of large scale large-scale Internet of Things (IoT) networks serves as the basis for wide deployment experience with RPL. The profile chosen for RPL in the ACP does not leverage any RPL specific RPL-specific forwarding plane features (IPv6 extension headers), making its implementation a pure control plane software requirement.</t>
        <t>GRASP
        <t indent="0" pn="section-1.1-7">GRASP is the only completely novel protocol used in the ACP, and this choice was necessary because there is no existing suitable protocol to provide suitable for providing the necessary functions to the ACP, so GRASP was developed to fill that gap.</t>
        <t>The
        <t indent="0" pn="section-1.1-8">The ACP design can be applicable to devices constrained with respect to cpu CPU and memory, and to networks constrained with respect to bitrate and reliability,
but this document does not attempt to define the most constrained type of devices or networks to which the ACP is applicable. RPL and DTLS for ACP secure channels are two protocol choices already making ACP more applicable to constrained environments. Support for constrained devices in this specification is opportunistic, but not complete, because the reliable transport for GRASP (see <xref target="GRASP-substrate" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 6.9.2"/>) only specifies TCP/TLS.  See <xref target="reuse-acp" format="default"/> format="default" sectionFormat="of" derivedContent="Appendix A.8"/> for discussions about how future standards or proprietary extensions/variations extensions and/or variations of the ACP could better meet different expectations that are different from those on upon which the current design is based based, including supporting constrained devices better.</t>
      </section>
      <!-- applicability -->
    </section>
    <!-- intro -->
    <section anchor="terminology" numbered="true" toc="default">
      <name>Acronyms toc="include" removeInRFC="false" pn="section-2">
      <name slugifiedName="name-acronyms-and-terminology-in">Acronyms and Terminology (Informative)</name>
      <t>[RFC-Editor: Please add ACP, BRSKI, GRASP, MASA to https://www.rfc-editor.org/materials/abbrev.expansion.txt.]</t>
      <t>[RFC-Editor: What is the recommended way to reference a hanging text, e.g. to
       a definition in the list of definitions? Up to -28, this document was using XMLv2
       and the only option I could find for RFC/XML to point to a hanging text was
       format="title", which leads to references such as '-&gt;"ACP certificate" ()', aka:
       redundant empty parenthesis. Many reviewers where concerned about this.
       I created a ticket to ask for an xml2rfc enhancement to avoid this
       in the future: https://trac.tools.ietf.org/tools/xml2rfc/trac/ticket/347. When i
       changed to XMLv3 in version -29, i could get rid of the unnecessary () by using
       format="none", but that format is declared to be deprecated in XMLv3. So i am not
       aware of any working AND "non-deprecated" option.]</t>

      <t>[RFC-Editor: Question: Is it possible to change the first occurrences of
        [RFCxxxx] references to "rfcxxx title" [RFCxxxx]? the XML2RFC format does
        not seem to offer such a format, but I did not want to duplicate 50 first
        references - one reference for title mentioning and one
        for RFC number.]</t>

      <t>This
      <t indent="0" pn="section-2-1">This document serves both as a normative specification for how ACP
        nodes have to behave
        node behavior as well as describing an explanation of the context by providing descriptions of requirements, benefits,
        architecture
        architecture, and operational aspects to explain the context. aspects.
        Normative sections are labelled labeled "(Normative)" and use BCP 14 keywords.
        Other sections are labelled labeled "(Informative)" and do not use those normative
        keywords.</t>
      <t>In
      <t indent="0" pn="section-2-2">In the rest of the document document, we will refer to systems using that use the ACP as "nodes".  Typically, such a node is a physical (network equipment) device, but it can equally be some virtualized system.  Therefore, we do not refer to them as devices unless the context specifically calls for a physical system.</t>
      <t>This
      <t indent="0" pn="section-2-3">This document introduces or uses the following terms (sorted alphabetically).  Terms introduced  Introduced terms are
        explained on first use, so this list is for reference only.</t>
      <dl spacing="compact">
        <dt>ACP:</dt>
        <dd>"Autonomic spacing="normal" newline="false" indent="3" pn="section-2-4">
        <dt pn="section-2-4.1">ACP:</dt>
        <dd pn="section-2-4.2">Autonomic Control Plane". Plane.  The Autonomic Function <xref target="af-def" format="none" sectionFormat="of" derivedContent="">autonomic function</xref> as defined in this document.
            It provides secure secure, zero-touch (automated) transitive (network wide) (network-wide) IPv6 connectivity for all nodes in the same ACP domain as well as a GRASP instance running across this ACP IPv6 connectivity.
            The ACP is primarily meant to be used as a component of the ANI <xref target="ani-def" format="none" sectionFormat="of" derivedContent="">ANI</xref> to enable Autonomic Networks <xref target="an-def" format="none" sectionFormat="of" derivedContent="">Autonomic Networks</xref>,
            but it can equally be used in simple ANI networks (with no other Autonomic Functions) autonomic functions) or
            completely by itself.
            </dd>
        <dt>ACP
        <dt pn="section-2-4.3">ACP address:</dt>
        <dd>An
        <dd pn="section-2-4.4">An IPv6 address assigned to the ACP node.  It is stored
            in the acp-node-name <xref target="acp-node-name-def" format="none" sectionFormat="of" derivedContent="">acp-node-name</xref> of the <xref target="domcert-def" format="none">-&gt;"ACP certificate"</xref>. format="none" sectionFormat="of" derivedContent="">ACP certificate</xref>.
            </dd>
        <dt>ACP
        <dt pn="section-2-4.5">ACP address range/set:</dt>
        <dd>The range or set:</dt>
        <dd pn="section-2-4.6">The ACP address may imply a range or set of addresses that the node can assign for different purposes.  This address range/set range or set is derived by the node from the format of the ACP address called the "addressing sub-scheme". addressing sub-scheme.
            </dd>
        <dt anchor="domcert-def" pn="section-2-4.7">ACP certificate:</dt>
        <dd pn="section-2-4.8">A Local Device IDentity (<xref target="ldevid" format="none" sectionFormat="of" derivedContent="">LDevID</xref>) certificate conforming to "<xref target="RFC5280" format="title" sectionFormat="of" derivedContent="Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile"/>" <xref target="RFC5280" format="default" sectionFormat="of" derivedContent="RFC5280"/> that carries the <xref target="acp-node-name-def" format="none" sectionFormat="of" derivedContent="">acp-node-name</xref>, which is used by the ACP to learn its address in the ACP and to derive and cryptographically assert its membership in the ACP domain.  In the context of the ANI, the ACP certificate is also called the ANI certificate.
In the context of AN, the ACP certificate is also called the AN certificate. </dd>
        <dt>ACP
        <dt pn="section-2-4.9">ACP connect interface:</dt>
        <dd>An
        <dd pn="section-2-4.10">An interface on an ACP node providing that provides access to the ACP for non ACP capable non-ACP-capable nodes without using an ACP secure channel.  See <xref target="NMS" format="default"/>. format="default" sectionFormat="of" derivedContent="Section 8.1.1"/>.
            </dd>
        <dt>ACP
        <dt pn="section-2-4.11">ACP domain:</dt>
        <dd>The
        <dd pn="section-2-4.12">The ACP domain is the set of nodes with <xref target="domcert-def" format="none">-&gt;"ACP certificates"</xref> format="none" sectionFormat="of" derivedContent="">ACP certificates</xref> that allow them to authenticate each other as members of the ACP domain.  See also <xref target="certcheck" format="default"/>.</dd>
        <dt>ACP (ANI/AN) certificate:</dt>
        <dd anchor="domcert-def">A <xref target="RFC5280" format="default"/> certificate (LDevID)
            carrying the acp-node-name which is used by the ACP to learn its address
            in the ACP and to derive and cryptographically assert its membership in the ACP domain.
            </dd>
        <dt>ACP acp-node-name field:</dt>
        <dd>An information field in the ACP certificate in
            which the ACP relevant information is encoded: the ACP domain name, the ACP IPv6 address of the node
            and optional additional role attributes about the node.
            </dd>
        <dt>ACP Loopback format="default" sectionFormat="of" derivedContent="Section 6.2.3"/>.</dd>
        <dt anchor="acp-loopback-def" pn="section-2-4.13">ACP loopback interface:</dt>
        <dd anchor="acp-loopback-def">The Loopback pn="section-2-4.14">The loopback interface in the ACP Virtual Routing and Forwarding (VRF) <xref target="vrf-def" format="none" sectionFormat="of" derivedContent="">VRF</xref> that has the ACP address assigned to it. See <xref target="ACP-loopback" format="default"/>. format="default" sectionFormat="of" derivedContent="Section 6.13.5.1"/>.
            </dd>
        <dt>ACP
        <dt pn="section-2-4.15">ACP network:</dt>
        <dd>The
        <dd pn="section-2-4.16">The ACP network constitutes comprises all the nodes that have access to the ACP.
            It is the set of active and transitively connected nodes of an ACP domain plus all nodes that get access to
            the ACP of that domain via ACP edge nodes.
            </dd>
        <dt>ACP
        <dt pn="section-2-4.17">ACP (ULA) prefix(es):</dt>
        <dd>The
        <dd pn="section-2-4.18">The /48 IPv6 address prefixes used across the ACP.  In the normal/simple normal or simple case, the ACP has one ULA <xref target="ula-def" format="none" sectionFormat="of" derivedContent="">Unique Local Address (ULA)</xref> prefix, see <xref target="addressing" format="default"/>. format="default" sectionFormat="of" derivedContent="Section 6.11"/>.  The ACP routing table may include multiple ULA prefixes if the "rsub" rsub option is used to create addresses from more than one ULA prefix.  See <xref target="domcert-acpinfo" format="default"/>. format="default" sectionFormat="of" derivedContent="Section 6.2.2"/>.  The ACP may also include non-ULA prefixes if those are configured on ACP connect interfaces.  See <xref target="NMS" format="default"/>. format="default" sectionFormat="of" derivedContent="Section 8.1.1"/>.
            </dd>
        <dt>ACP
        <dt pn="section-2-4.19">ACP secure channel:</dt>
        <dd>A
        <dd pn="section-2-4.20">A channel authenticated via <xref target="domcert-def" format="none">-&gt;"ACP certificates"</xref> format="none" sectionFormat="of" derivedContent="">ACP certificates</xref> providing integrity protection and confidentiality through encryption. These channels are established between (normally) adjacent ACP nodes to carry traffic of the ACP VRF securely and isolated from Data-Plane <xref target="vrf-def" format="none" sectionFormat="of" derivedContent="">VRF</xref> traffic in-band over the same link/path links and paths as data plane traffic but isolate it from the Data-Plane. data plane traffic and secure it.
            </dd>
        <dt>ACP
        <dt pn="section-2-4.21">ACP secure channel protocol:</dt>
        <dd>The
        <dd pn="section-2-4.22">The protocol used to build an ACP secure channel,
            e.g., Internet Key Exchange Protocol version 2 (IKEv2) with IPsec or Datagram Transport Layer Security (DTLS). DTLS.
            </dd>
        <dt>ACP
        <dt pn="section-2-4.23">ACP virtual interface:</dt>
        <dd>An
        <dd pn="section-2-4.24">An interface in the ACP VRF <xref target="vrf-def" format="none" sectionFormat="of" derivedContent="">VRF</xref> mapped to one or more
            ACP secure channels.  See <xref target="ACP_interfaces" format="default"/>.
            </dd>
        <dt>AN</dt>
        <dd>"Autonomic Network": A network according to <xref target="I-D.ietf-anima-reference-model" format="default"/>.
            Its main components are ANI, Autonomic Functions and Intent. format="default" sectionFormat="of" derivedContent="Section 6.13.5"/>.
            </dd>
        <dt>(AN) Domain Name:</dt>
        <dd>An FQDN (Fully Qualified Domain Name)
        <dt anchor="acp-node-name-def" pn="section-2-4.25">acp-node-name field:</dt>
        <dd pn="section-2-4.26">An information field in the acp-node-name of the Domain Certificate.  See <xref target="domcert-acpinfo" format="default"/>.
            </dd>
        <dt>ANI target="domcert-def" format="none" sectionFormat="of" derivedContent="">ACP certificate</xref> in which the following ACP-relevant information is encoded: the ACP domain name, the ACP IPv6 address of the node, and optional additional role attributes about the node.  </dd>
        <dt anchor="an-def" pn="section-2-4.27">AN:</dt>
        <dd pn="section-2-4.28">Autonomic Network. A network according to <xref target="RFC8993" format="default" sectionFormat="of" derivedContent="RFC8993"/>.
            Its main components are <xref target="ani-def" format="none" sectionFormat="of" derivedContent="">ANI</xref>, <xref target="af-def" format="none" sectionFormat="of" derivedContent="">autonomic functions</xref>, and <xref target="intent-def" format="none" sectionFormat="of" derivedContent="">Intent</xref>.
            </dd>
        <dt pn="section-2-4.29">(AN) Domain Name:</dt>
        <dd pn="section-2-4.30">An FQDN (Fully Qualified Domain Name) in the acp-node-name of the domain certificate.  See <xref target="domcert-acpinfo" format="default" sectionFormat="of" derivedContent="Section 6.2.2"/>.
            </dd>
        <dt anchor="ani-def" pn="section-2-4.31">ANI (nodes/network):</dt>
        <dd>"Autonomic
        <dd pn="section-2-4.32">Autonomic Network Infrastructure". Infrastructure.
            The ANI is the infrastructure to enable Autonomic Networks. <xref target="an-def" format="none" sectionFormat="of" derivedContent="">Autonomic Networks</xref>.  It includes ACP, BRSKI BRSKI, and GRASP.
            Every Autonomic Network includes the ANI, but not every ANI network needs to include autonomic functions <xref target="af-def" format="none" sectionFormat="of" derivedContent="">autonomic functions</xref> beyond the ANI (nor Intent). <xref target="intent-def" format="none" sectionFormat="of" derivedContent="">Intent</xref>).  An ANI network without further autonomic functions can can, for example example, support secure zero-touch (automated) bootstrap
            and stable connectivity for SDN networks - networks, see <xref target="RFC8368" format="default"/>. format="default" sectionFormat="of" derivedContent="RFC8368"/>.
            </dd>
        <dt>ANIMA:</dt>
        <dd>"Autonomic
        <dt pn="section-2-4.33">ANIMA:</dt>
        <dd pn="section-2-4.34">Autonomic Networking Integrated Model and Approach". Approach.
            ACP, BRSKI BRSKI, and GRASP are specifications of the IETF ANIMA working group. Working Group.
            </dd>
        <dt>ASA:</dt>
        <dd>"Autonomic
        <dt pn="section-2-4.35">ASA:</dt>
        <dd pn="section-2-4.36">Autonomic Service Agent". Agent.  Autonomic software modules running on
            an ANI <xref target="ani-def" format="none" sectionFormat="of" derivedContent="">ANI</xref> device.  The components making up the ANI (BRSKI, ACP, and GRASP) are also described as ASAs.
            </dd>
        <dt>Autonomic Function:</dt>
        <dd>A function/service
        <dt anchor="af-def" pn="section-2-4.37">autonomic function:</dt>
        <dd pn="section-2-4.38">A function and/or service in an Autonomic Network (AN)
            composed of one or more ASA ASAs across one or more ANI nodes.
            </dd>
        <dt>BRSKI:</dt>
        <dd>"Bootstrapping
        <dt pn="section-2-4.39">BRSKI:</dt>
        <dd pn="section-2-4.40">Bootstrapping Remote Secure Key Infrastructures"
            (<xref target="I-D.ietf-anima-bootstrapping-keyinfra" format="default"/>. Infrastructure
            <xref target="RFC8995" format="default" sectionFormat="of" derivedContent="RFC8995"/>.  A protocol extending EST <xref target="est-def" format="none" sectionFormat="of" derivedContent="">EST</xref> to
            enable secure zero-touch bootstrap in conjunction with ACP.  ANI nodes use ACP, BRSKI BRSKI, and GRASP.
            </dd>
        <dt>CA:</dt>
        <dt anchor="ca-def" pn="section-2-4.41">CA:</dt>
        <dd anchor="ca-def">"Certification Authority". pn="section-2-4.42">Certification Authority. An entity that issues digital certificates. A CA uses its private key to sign the certificates it issues. Relying parties use the public key in the CA certificate to validate the signature.</dd>
        <dt>CRL:</dt>
        <dd>"Certificate
        <dt pn="section-2-4.43">CRL:</dt>
        <dd pn="section-2-4.44">Certificate Revocation List". List. A list of revoked certificates. Required certificates is required to revoke certificates before their lifetime expires.
            </dd>
        <dt>Data-Plane:</dt>
        <dd>The
        <dt pn="section-2-4.45">data plane:</dt>
        <dd pn="section-2-4.46">The counterpoint to the ACP VRF <xref target="vrf-def" format="none" sectionFormat="of" derivedContent="">VRF</xref> in an ACP node: the forwarding of user traffic and
            in non-autonomous nodes/networks nodes and/or networks and also any non-autonomous control and/or management plane functions.
            In a fully Autonomic Network <xref target="an-def" format="none" sectionFormat="of" derivedContent="">Autonomic Network</xref> node, the Data-Plane data plane is managed autonomically via Autonomic
            Functions <xref target="af-def" format="none" sectionFormat="of" derivedContent="">autonomic
            functions</xref> and Intent. <xref target="intent-def" format="none" sectionFormat="of" derivedContent="">Intent</xref>. See <xref target="intro" format="default"/> format="default" sectionFormat="of" derivedContent="Section 1"/> for more detailed explanations. details.
            </dd>
        <dt>device:</dt>
        <dd>A
        <dt pn="section-2-4.47">device:</dt>
        <dd pn="section-2-4.48">A physical system, system or physical node.</dd>
        <dt>Enrollment:</dt>
        <dd>The
        <dt anchor="enrollment-def" pn="section-2-4.49">enrollment:</dt>
        <dd pn="section-2-4.50">The process through by which a node authenticates itself to a
            network with an initial identity, which is often called IDevID an <xref target="idevid-def" format="none" sectionFormat="of" derivedContent="">Initial Device IDentity (IDevID)</xref> certificate, and acquires from the network
            a network specific network-specific identity, which is often called LDevID an <xref target="ldevid" format="none" sectionFormat="of" derivedContent="">LDevID</xref> certificate, and certificates of one or more Trust Anchor(s). <xref target="ta-def" format="none" sectionFormat="of" derivedContent="">trust anchor(s)</xref>.
            In the ACP, the LDevID certificate is called the ACP certificate. <xref target="domcert-def" format="none" sectionFormat="of" derivedContent="">ACP certificate</xref>.
            </dd>
        <dt>EST:</dt>
        <dd>"Enrollment
        <dt anchor="est-def" pn="section-2-4.51">EST:</dt>
        <dd pn="section-2-4.52">Enrollment over Secure Transport" (<xref Transport <xref target="RFC7030" format="default"/>). format="default" sectionFormat="of" derivedContent="RFC7030"/>.  IETF
            standard-track
            Standards Track protocol for enrollment of a node with an LDevID <xref target="ldevid" format="none" sectionFormat="of" derivedContent="">LDevID</xref> certificate.  BRSKI is based on EST.
            </dd>
        <dt>GRASP:</dt>
        <dd>"Generic
        <dt pn="section-2-4.53">GRASP:</dt>
        <dd pn="section-2-4.54">GeneRic Autonomic Signaling Protocol". Protocol.  An extensible signaling
            protocol required by the ACP for ACP neighbor discovery.</dd>
        <dt/>
        <dd>The
        <dt pn="section-2-4.55"/>
        <dd pn="section-2-4.56">The ACP also provides the
            "security and transport substrate" for the "ACP instance of GRASP". This instance
            of GRASP runs across the ACP secure channels to support BRSKI and other NOC/OAM NOC and/or OAM or
            Autonomic Functions.
            <xref target="af-def" format="none" sectionFormat="of" derivedContent="">autonomic functions</xref>.  See <xref target="I-D.ietf-anima-grasp" format="default"/>. target="RFC8990" format="default" sectionFormat="of" derivedContent="RFC8990"/>.
            </dd>
        <dt>IDevID:</dt>
        <dd>An "Initial
        <dt anchor="idevid-def" pn="section-2-4.57">IDevID:</dt>
        <dd pn="section-2-4.58">An Initial Device IDentity" IDentity X.509 certificate installed by
            the vendor on new equipment.  Contains  The IDevID certificate contains information that establishes the identity of the
            node in the context of its vendor/manufacturer vendor and/or manufacturer such as device model/type model and/or type
            and serial number.  See <xref target="AR8021" format="default"/>. format="default" sectionFormat="of" derivedContent="AR8021"/>. The IDevID certificate cannot be used as a node identifier for the
            ACP because they are not provisioned by the owner of the network, so they can
            not directly indicate an ACP domain they belong to.
            </dd>
        <dt>in-band (management/signaling):</dt>
        <dt anchor="in-band-def" pn="section-2-4.59">in-band (as in management or signaling):</dt>
        <dd anchor="in-band-def"> pn="section-2-4.60">
            In-band management traffic and/or control plane signaling uses the same network
            resources such as routers/switches routers and/or switches and network links that it manages/controls. manages and/or controls.
            In-band is the standard management and signaling mechanism in IP networks.
            Compared to <xref target="out-of-band-def" format="none">-&gt;"out-of-band"</xref> it format="none" sectionFormat="of" derivedContent="">out-of-band</xref>, the in-band mechanism
            requires no additional physical resources, but it introduces potentially circular
            dependencies for its correct operations.
            See <xref target="intro" format="none">-&gt;"introduction"</xref>. format="default" sectionFormat="of" derivedContent="Section 1"/>.
            </dd>
        <dt>Intent:</dt>
        <dd>Policy
        <dt anchor="intent-def" pn="section-2-4.61">Intent:</dt>
        <dd pn="section-2-4.62">The policy language of an autonomic network Autonomic Network according to <xref target="I-D.ietf-anima-reference-model" format="default"/>. target="RFC8993" format="default" sectionFormat="of" derivedContent="RFC8993"/>.
            </dd>
        <dt>Loopback
        <dt pn="section-2-4.63">Loopback interface:</dt>
        <dd>See
        <dd pn="section-2-4.64">See
            <xref target="acp-loopback-def" format="none">-&gt;"ACP Loopback interface"</xref>. format="none" sectionFormat="of" derivedContent="">ACP loopback interface</xref>.
            </dd>
        <dt>LDevID:</dt>
        <dd>A "Local
        <dt anchor="ldevid" pn="section-2-4.65">LDevID:</dt>
        <dd pn="section-2-4.66">A Local Device IDentity" IDentity is an X.509 certificate installed during
            "enrollment".
            <xref target="enrollment-def" format="none" sectionFormat="of" derivedContent="">enrollment</xref>.  The Domain Certificate <xref target="domcert-def" format="none" sectionFormat="of" derivedContent="">domain certificate</xref> used by the ACP is an LDevID certificate.  See <xref target="AR8021" format="default"/>. format="default" sectionFormat="of" derivedContent="AR8021"/>.
            </dd>
        <dt>Management:</dt>
        <dd>Used
        <dt pn="section-2-4.67">management:</dt>
        <dd pn="section-2-4.68">Used in this document as another word for <xref target="OAM" format="none">-&gt;"OAM"</xref>. format="none" sectionFormat="of" derivedContent="">OAM</xref>.
            </dd>
        <dt>MASA
        <dt pn="section-2-4.69">MASA (service):</dt>
        <dd>"Manufacturer
        <dd pn="section-2-4.70">Manufacturer Authorized Signing Authority". Authority.  A vendor/manufacturer vendor and/or manufacturer
            or delegated cloud service on the Internet used as part of the BRSKI protocol.
            </dd>
        <dt>MIC:</dt>
        <dd>"Manufacturer
        <dt pn="section-2-4.71">MIC:</dt>
        <dd pn="section-2-4.72">Manufacturer Installed Certificate".  This is another word to describe Certificate.  A synonym for an IDevID <xref target="idevid-def" format="none" sectionFormat="of" derivedContent="">IDevID</xref> in referenced materials. This term is not used in this document.
            </dd>
        <dt>native
        <dt pn="section-2-4.73">native interface:</dt>
        <dd>Interfaces
        <dd pn="section-2-4.74">Interfaces existing on a node without configuration of the already running node.  On physical nodes nodes, these are usually physical interfaces; on virtual nodes nodes, their equivalent.
            </dd>
        <dt>NOC:</dt>
        <dd>Network
        <dt pn="section-2-4.75">NOC:</dt>
        <dd pn="section-2-4.76">Network Operations Center.
            </dd>
        <dt>node:</dt>
        <dd>A
        <dt pn="section-2-4.77">node:</dt>
        <dd pn="section-2-4.78">A system supporting the ACP according to this document.  Can  A node can be virtual or physical.  Physical nodes are called devices.
            </dd>
        <dt>Node-ID:</dt>
        <dt anchor="node-id" pn="section-2-4.79">Node-ID:</dt>
        <dd anchor="node-id"> pn="section-2-4.80">
            The identifier of an ACP node inside that ACP. It is either the last 64 bits (see <xref target="zone-scheme" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 6.11.3"/>) or 78-bits 78 bits (see <xref target="Vlong" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 6.11.5"/>) of the ACP address.
            </dd>
        <dt>OAM:</dt>
        <dt anchor="OAM" pn="section-2-4.81">OAM:</dt>
        <dd anchor="OAM">Operations, Administration pn="section-2-4.82">Operations, Administration, and Management. Includes Network Monitoring. network monitoring.
            </dd>
        <dt>Operational
        <dt anchor="ot" pn="section-2-4.83">Operational Technology (OT):</dt>
        <dd anchor="ot"><eref target="https://en.wikipedia.org/wiki/Operational_Technology"/>: pn="section-2-4.84">
             "The hardware and software dedicated to detecting or causing changes
              in physical processes through direct monitoring and/or control of physical
              devices such as valves, pumps, etc.". etc." <xref target="OP-TECH" format="default" sectionFormat="of" derivedContent="OP-TECH"/>. In most cases today, OT networks are today in most cases
              well separated from Information Technology (IT) networks.
             </dd>
        <dt>out-of-band
        <dt anchor="out-of-band-def" pn="section-2-4.85">out-of-band (management) network:</dt>
        <dd anchor="out-of-band-def"> pn="section-2-4.86">
             An out-of-band network is a secondary network
             used to manage a primary network. The equipment of the primary network is connected to
             the out-of-band network via dedicated management ports on the primary network equipment.
             Serial (console) management ports were historically most common, higher end common; however, higher-end network equipment
             now also has ethernet Ethernet ports dedicated only for to management. An out-of-band network provides
             management access to the primary network independent of the configuration state of the primary
             network.  See <xref target="intro" format="none">-&gt;"Introduction"</xref></dd>
        <dt>(virtual) out-of-band network:</dt> format="default" sectionFormat="of" derivedContent="Section 1"/>.</dd>
        <dt anchor="virtual-out-of-band-def" pn="section-2-4.87">out-of-band network, virtual:</dt>
        <dd anchor="virtual-out-of-band-def"> pn="section-2-4.88">
             The ACP can be called a virtual out-of-band network for management and control
             because it attempts to provide the benefits of a (physical)
             <xref target="out-of-band-def" format="none">-&gt;"out-of-band network"</xref> format="none" sectionFormat="of" derivedContent="">out-of-band network</xref>
             even though it is physically carried <xref target="in-band-def" format="none">-&gt;"in-band"</xref>. format="none" sectionFormat="of" derivedContent="">in-band</xref>.
             See <xref target="intro" format="none">-&gt;"introduction"</xref>. format="default" sectionFormat="of" derivedContent="Section 1"/>.
            </dd>
        <dt>root
        <dt pn="section-2-4.89">root CA:</dt>
        <dd>"root
        <dd pn="section-2-4.90">root Certification Authority". Authority. A <xref target="ca-def" format="none">-&gt;"CA"</xref> format="none" sectionFormat="of" derivedContent="">CA</xref> for which the root CA Key key update
	procedures of <xref target="RFC7030" format="default"/>, Section 4.4 sectionFormat="comma" section="4.4" format="default" derivedLink="https://rfc-editor.org/rfc/rfc7030#section-4.4" derivedContent="RFC7030"/>, can be applied.
            </dd>
        <dt>RPL:</dt>
        <dd>"IPv6
        <dt pn="section-2-4.91">RPL:</dt>
        <dd pn="section-2-4.92">IPv6 Routing Protocol for Low-Power and Lossy Networks". Networks.  The routing protocol used in the ACP. See <xref target="RFC6550" format="default"/>. format="default" sectionFormat="of" derivedContent="RFC6550"/>.
            </dd>
        <dt>(ACP/ANI/BRSKI) Registrar:</dt>
        <dd>
        <dt pn="section-2-4.93">registrar (ACP, ANI/BRSKI):</dt>
        <dd pn="section-2-4.94">
            An ACP registrar is an entity (software and/or person) that is orchestrating orchestrates
            the enrollment <xref target="enrollment-def" format="none" sectionFormat="of" derivedContent="">enrollment</xref> of ACP nodes with the ACP certificate. <xref target="domcert-def" format="none" sectionFormat="of" derivedContent="">ACP certificate</xref>. ANI nodes use
            BRSKI, so ANI registrars are also called BRSKI registrars. For non-ANI ACP nodes,
            the registrar mechanisms are undefined by not defined in this document. See <xref target="acp-registrars" format="default"/>. format="default" sectionFormat="of" derivedContent="Section 6.11.7"/>.
            Renewal and other maintenance (such as revocation) of ACP certificates
            may be performed by other entities other than registrars. EST must be supported for
            ACP certificate renewal (see <xref target="domcert-maint" format="default"/>). format="default" sectionFormat="of" derivedContent="Section 6.2.5"/>). BRSKI
            is an extension of EST, so ANI/BRSKI registrars can easily support ACP domain
            certificate renewal in addition to initial enrollment.
            </dd>
        <dt>RPI:</dt>
        <dd>"RPL
        <dt pn="section-2-4.95">RPI:</dt>
        <dd pn="section-2-4.96">RPL Packet Information". Information. Network extension headers for use with the
            <xref target="rpl-def" format="none">-&gt;"RPL"</xref> routing protocols. format="none" sectionFormat="of" derivedContent="">RPL</xref>.
            Not used with RPL in the ACP. See <xref target="rpl-Data-Plane" format="default"/>. format="default" sectionFormat="of" derivedContent="Section 6.12.1.13"/>.
            </dd>
        <dt>RPL:</dt>
        <dt anchor="rpl-def" pn="section-2-4.97">RPL:</dt>
        <dd anchor="rpl-def">"Routing pn="section-2-4.98">Routing Protocol for Low-Power and Lossy Networks". Networks. The routing protocol used in the ACP.  See <xref target="routing" format="default"/>. format="default" sectionFormat="of" derivedContent="Section 6.12"/>.
            </dd>
        <dt>sUDI:</dt>
        <dd>"secured
        <dt anchor="sudi" pn="section-2-4.99">sUDI:</dt>
        <dd pn="section-2-4.100">secured Unique Device Identifier". Identifier.  This is another word to describe an a synonym of IDevID in referenced material.  This term is not used in this document.
            </dd>
        <dt>TA:</dt>
        <dt anchor="ta-def" pn="section-2-4.101">TA:</dt>
        <dd anchor="ta-def">"Trust Anchor". pn="section-2-4.102">Trust Anchor. A Trust Anchor TA is an entity that
	is trusted for the purpose of certificate validation. Trust Anchor Information TA
	information such as self-signed certificate(s) of the Trust Anchor TA is
	configured into the ACP node as part of Enrollment. <xref target="enrollment-def" format="none" sectionFormat="of" derivedContent="">enrollment</xref>. See <xref target="RFC5280" format="default"/>, Section 6.1.1. sectionFormat="comma" section="6.1.1" format="default" derivedLink="https://rfc-editor.org/rfc/rfc5280#section-6.1.1" derivedContent="RFC5280"/>.
            </dd>
        <dt>UDI:</dt>
        <dd>"Unique
        <dt pn="section-2-4.103">UDI:</dt>
        <dd pn="section-2-4.104">Unique Device Identifier". Identifier.  In the context of this document document, unsecured
            identity information of a node typically consisting consists of at least a device model/type model and/or type and a
            serial number, often in a vendor specific vendor-specific format.  See sUDI <xref target="sudi" format="none" sectionFormat="of" derivedContent="">sUDI</xref> and LDevID. <xref target="ldevid" format="none" sectionFormat="of" derivedContent="">LDevID</xref>.
            </dd>
        <dt>ULA:
        <dt anchor="ula-def" pn="section-2-4.105">ULA (Global ID prefix)</dt>
        <dd> prefix):</dt>
        <dd pn="section-2-4.106">
            A "Unique Unique Local Address" (ULA) Address is an IPv6
            address in the block fc00::/7, defined in [RFC4193]. "<xref target="RFC4193" format="title" sectionFormat="of" derivedContent="Unique Local IPv6 Unicast Addresses"/>" <xref target="RFC4193" format="default" sectionFormat="of" derivedContent="RFC4193"/>.  ULA is the
            IPv6 successor of the IPv4 private address space (<xref ("<xref target="RFC1918" format="default"/>).
            ULA format="title" sectionFormat="of" derivedContent="Address Allocation for Private Internets"/>" <xref target="RFC1918" format="default" sectionFormat="of" derivedContent="RFC1918"/>).
            ULAs have important differences over IPv4 private addresses that
            are beneficial for and exploited by the ACP, such as the Locally
            Assigned locally
            assigned Global ID prefix, which are is the first 48-bits 48 bits of a ULA
            address <xref target="RFC4193" format="default"/>, section 3.2.1. sectionFormat="comma" section="3.2.1" format="default" derivedLink="https://rfc-editor.org/rfc/rfc4193#section-3.2.1" derivedContent="RFC4193"/>.
            In this document document, this prefix is abbreviated as "ULA prefix".
            </dd>
        <dt>(ACP)
        <dt anchor="vrf-def" pn="section-2-4.107">(ACP) VRF:</dt>
        <dd>The
        <dd pn="section-2-4.108">The ACP is modeled in this document as a "Virtual Virtual Routing and Forwarding" instance (VRF). Forwarding instance. This means that it is based on a "virtual router" consisting of a separate IPv6 forwarding table to which the ACP virtual interfaces are attached and an associated IPv6 routing table separate from the Data-Plane. data plane. Unlike the VRFs on MPLS/VPN-PE (<xref MPLS/VPN Provider Edge ("<xref target="RFC4364" format="title" sectionFormat="of" derivedContent="BGP/MPLS IP Virtual Private Networks (VPNs)"/>" <xref target="RFC4364" format="default"/>) format="default" sectionFormat="of" derivedContent="RFC4364"/>) or LISP XTR (<xref xTR ("<xref target="RFC6830" format="title" sectionFormat="of" derivedContent="The Locator/ID Separation Protocol (LISP)"/>" <xref target="RFC6830" format="default"/>), format="default" sectionFormat="of" derivedContent="RFC6830"/>), the ACP VRF does not have any special "core facing" functionality or routing/mapping routing and/or mapping protocols shared across multiple VRFs. In vendor products products, a VRF such as the ACP-VRF ACP VRF may also be referred to as a so called VRF-lite.
            </dd>
        <dt>(ACP)
        <dt pn="section-2-4.109">(ACP) Zone:</dt>
        <dd>An
        <dd pn="section-2-4.110">An ACP zone is a set of ACP nodes using the same zone field value in their ACP address according to <xref target="zone-scheme" format="default"/>. format="default" sectionFormat="of" derivedContent="Section 6.11.3"/>. Zones are a mechanism to support structured addressing of ACP addresses within the same /48-bit /48 ULA prefix.
            </dd>
      </dl>
      <t>
      <t indent="0" pn="section-2-5">
    The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED",  "MAY", "<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>", "<bcp14>REQUIRED</bcp14>", "<bcp14>SHALL</bcp14>", "<bcp14>SHALL NOT</bcp14>", "<bcp14>SHOULD</bcp14>", "<bcp14>SHOULD NOT</bcp14>", "<bcp14>RECOMMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>",
    "<bcp14>MAY</bcp14>", and "OPTIONAL" "<bcp14>OPTIONAL</bcp14>" in this document are to be interpreted as
    described in BCP 14 [RFC2119],[RFC8174] BCP 14 <xref target="RFC2119" format="default" sectionFormat="of" derivedContent="RFC2119"/> <xref target="RFC8174" format="default" sectionFormat="of" derivedContent="RFC8174"/>
    when, and only when, they appear in all capitals, as shown here.
      </t>
    </section>
    <section anchor="usage" numbered="true" toc="default">
      <name>Use toc="include" removeInRFC="false" pn="section-3">
      <name slugifiedName="name-use-cases-for-an-autonomic-">Use Cases for an Autonomic Control Plane (Informative)</name>
      <t>This
      <t indent="0" pn="section-3-1">This section summarizes the use cases that are intended to be supported by an ACP. To understand how these are derived from and relate to the larger set of use cases for autonomic networks, Autonomic Networks, please refer to "<xref target="RFC8316" format="title" sectionFormat="of" derivedContent="Autonomic Networking Use Case for Distributed Detection of Service Level Agreement (SLA) Violations"/>" <xref target="RFC8316" format="default"/>.</t> format="default" sectionFormat="of" derivedContent="RFC8316"/>.</t>
      <section anchor="infrastructure" numbered="true" toc="default">
        <name>An toc="include" removeInRFC="false" pn="section-3.1">
        <name slugifiedName="name-an-infrastructure-for-auton">An Infrastructure for Autonomic Functions</name>
        <t>Autonomic Functions
        <t indent="0" pn="section-3.1-1">Autonomic functions need a stable infrastructure to run on, and all autonomic functions should use the same infrastructure to minimize the complexity of the network.  In this way, there is only need for a single discovery mechanism, a single security mechanism, and single instances of other processes that distributed functions require.</t>
      </section>
      <!-- infrastructure -->
      <section anchor="secure-bootstrap" numbered="true" toc="default">
        <name>Secure toc="include" removeInRFC="false" pn="section-3.2">
        <name slugifiedName="name-secure-bootstrap-over-an-un">Secure Bootstrap over a not configured an Unconfigured Network</name>
        <t>Today,
        <t indent="0" pn="section-3.2-1">Today, bootstrapping a new node typically requires all nodes between a controlling node such as an SDN controller ("Software Defined Networking", see (see <xref target="RFC7426" format="default"/>) format="default" sectionFormat="of" derivedContent="RFC7426"/>) and the new node to be completely and correctly addressed, configured configured, and secured.  Bootstrapping and configuration of a network happens in rings around the controller - -- configuring each ring of devices before the next one can be bootstrapped.  Without console access (for example example, through an out-of-band network) network), it is not possible today to make devices securely reachable before having configured the entire network leading up to them.</t>
        <t>With
        <t indent="0" pn="section-3.2-2">With the ACP, secure bootstrap of new devices and whole new networks can happen without requiring any configuration of unconfigured devices along the path: path. As long as all devices along the path support ACP and a zero-touch bootstrap mechanism such as BRSKI, the ACP across a whole network of unconfigured devices can be brought up without operator/provisioning operator and/or provisioning intervention. The ACP also provides offers additional security for any bootstrap mechanism, mechanism because it can provide the encrypted discovery (via ACP GRASP) of registrars or other bootstrap servers by bootstrap proxies connecting to nodes that are to be bootstrapped and the bootstrapped. The ACP encryption hides the identities of the communicating entities (pledge and registrar), making it more difficult to learn which network node might be attackable. The ACP certificate can also be used to end-to-end encrypt the bootstrap communication between such proxies and server. Note that bootstrapping here includes not only the first step that can be provided by BRSKI (secure keys), but also later stages where configuration is bootstrapped.</t>
      </section>
      <!-- bootstrap -->
      <section anchor="reachability" numbered="true" toc="default">
        <name>Data-Plane toc="include" removeInRFC="false" pn="section-3.3">
        <name slugifiedName="name-permanent-reachability-inde">Permanent Reachability Independent Permanent Reachability</name>
        <t>Today, of the Data Plane</name>
        <t indent="0" pn="section-3.3-1">Today, most critical control plane protocols and OAM protocols are using use the Data-Plane data plane of the network.  This leads to often undesirable dependencies between the control and OAM plane on one side and the Data-Plane data plane on the other: Only only if the forwarding and control plane of the Data-Plane data plane are configured correctly, will the Data-Plane data plane and the OAM/control OAM and/or control plane work as expected.</t>
        <t>Data-Plane
        <t indent="0" pn="section-3.3-2">Data plane connectivity can be affected by errors and faults, for example faults. Examples include misconfigurations that make AAA (Authentication, Authorization Authorization, and Accounting) servers unreachable or that can lock an administrator out of a device; routing or addressing issues can make a device unreachable; and shutting down interfaces over which a current management session is running can lock an admin administrator irreversibly out of the device.  Traditionally only out-of-band access via a serial console or Ethernet management port can help recover from such issues (such as serial console or ethernet management port).</t>
        <t>Data-Plane issues.</t>
        <t indent="0" pn="section-3.3-3">Data plane dependencies also affect applications in a Network Operations Center (NOC) NOC such as SDN controller applications: Certain certain network changes are today hard to implement, implement today because the change itself may affect reachability of the devices.  Examples are include address or mask changes, routing changes, or security policies.  Today such changes require precise precise, hop-by-hop planning.</t>
        <t>Note
        <t indent="0" pn="section-3.3-4">Note that specific control plane functions for the Data-Plane data plane often want to depend on forwarding of the ability to forward their packets via the Data-Plane: Aliveness data plane: sending aliveness and routing protocol signaling packets across the Data-Plane data plane to verify reachability across the Data-Plane, reachability, using IPv4 signaling packets for IPv4 routing vs. and IPv6 signaling packets for IPv6 routing.</t>
        <t>Assuming
        <t indent="0" pn="section-3.3-5">Assuming appropriate implementation (see <xref target="general_addressing" format="default"/> format="default" sectionFormat="of" derivedContent="Section 6.13.2"/> for more details), the ACP provides reachability that is independent of the Data-Plane. data plane. This  allows the control plane and OAM plane to operate more robustly:
        </t>
        <ul spacing="compact">
          <li>For spacing="normal" bare="false" empty="false" indent="3" pn="section-3.3-6">
          <li pn="section-3.3-6.1">For management plane protocols, the ACP provides the functionality of a Virtual out-of-band out-of-Band (VooB) channel, by providing connectivity to all nodes regardless of their Data-Plane data plane configuration, and routing and forwarding tables.</li>
          <li>For
          <li pn="section-3.3-6.2">For control plane protocols, the ACP allows their operation even when the Data-Plane data plane is temporarily faulty, or during transitional events, such as routing changes, which may affect the control plane at least temporarily.  This is specifically important for autonomic service agents, which could affect Data-Plane data plane connectivity.</li>
        </ul>
        <t>The
        <t indent="0" pn="section-3.3-7">The document <xref target="RFC8368" format="default">"Using format="default" sectionFormat="of" derivedContent="RFC8368">"Using Autonomic Control Plane for Stable Connectivity of Network OAM"</xref> explains this use case for the ACP in significantly more detail and explains how the ACP can be used in practical network operations.</t>
      </section>
      <!-- reachability -->
    </section>
    <!-- usage -->
    <section anchor="requirements" numbered="true" toc="default">
      <name>Requirements toc="include" removeInRFC="false" pn="section-4">
      <name slugifiedName="name-requirements-informative">Requirements (Informative)</name>
      <t>The
      <t indent="0" pn="section-4-1">The following requirements were identified for the design of the ACP based on the above use-cases use cases (<xref target="usage" format="default"/>). format="default" sectionFormat="of" derivedContent="Section 3"/>). These requirements are informative. The ACP as specified in the normative parts of this document is meeting or exceeding these use-case use case requirements:</t>
      <ol type="ACP%d:" spacing="compact">
        <li>The spacing="normal" indent="10" start="1" pn="section-4-2">
        <li anchor="acp1" pn="section-4-2.1" derivedCounter="ACP1:">The ACP should provide robust connectivity: As as far as possible, it should be independent of configured addressing, configuration configuration, and routing.  Requirements 2 and 3 build on this requirement, but they also have value on their own.</li>
        <li>The
        <li pn="section-4-2.2" derivedCounter="ACP2:">The ACP must have a separate address space from the Data-Plane.  Reason: data plane.  This separate address space provides traceability, debug-ability, ease of debugging, separation from Data-Plane, data plane, and infrastructure security (filtering based on known address space).</li>
        <li>The
        <li pn="section-4-2.3" derivedCounter="ACP3:">The ACP must use an autonomically managed address space.  Reason: easy  An autonomically managed address space provides ease of bootstrap and setup ("autonomic"); ("autonomic"), and robustness (admin (the administrator cannot break network easily).  This document uses Unique Local Addresses (ULA) ULA for this purpose, see <xref target="RFC4193" format="default"/>.</li>
        <li>The format="default" sectionFormat="of" derivedContent="RFC4193"/>.</li>
        <li anchor="acp4" pn="section-4-2.4" derivedCounter="ACP4:">The ACP must be generic, that is is, it must be usable by all the functions and protocols of the ANI.  Clients of the ACP must not be tied to a particular application or transport protocol.</li>
        <li>The
        <li pn="section-4-2.5" derivedCounter="ACP5:">The ACP must provide security: Messages messages coming through the ACP must be authenticated to be from a trusted node, and it is very strongly > recommended that they be encrypted.</li>
      </ol>
      <t>Explanation
      <t indent="0" pn="section-4-3">The explanation for ACP4: In <xref target="acp4" format="none" sectionFormat="of" derivedContent="">ACP4</xref> is as follows: in a fully autonomic network Autonomic Network (AN), all newly written ASAs could potentially all communicate exclusively via GRASP with each other, other exclusively via GRASP, and if that was assumed to be were the only requirement against for the ACP, it would not need to provide IPv6 layer IPv6-layer connectivity between nodes, but only GRASP connectivity. Nevertheless, because ACP also intends to support non-AN non-autonomous networks, it is crucial to support IPv6 layer IPv6-layer connectivity across the ACP to support any transport transport-layer and application layer application-layer protocols.</t>
      <t>The
      <t indent="0" pn="section-4-4">The ACP operates hop-by-hop, hop-by-hop because this interaction can be built on IPv6 link local link-local addressing, which is autonomic, and has no dependency on configuration (requirement 1). <xref target="acp1" format="none" sectionFormat="of" derivedContent="">ACP1</xref>).  It may be necessary to have ACP connectivity across non-ACP nodes, for example example, to link ACP nodes over the general Internet.  This is possible, but it introduces a dependency against stable/resilient on stable and/or resilient routing over the non-ACP hops (see <xref target="remote-acp-neighbors" format="default"/>).</t> format="default" sectionFormat="of" derivedContent="Section 8.2"/>).</t>
    </section>
    <!-- requirements -->
    <section anchor="overview" numbered="true" toc="default">
      <name>Overview toc="include" removeInRFC="false" pn="section-5">
      <name slugifiedName="name-overview-informative">Overview (Informative)</name>
      <t>When
      <t indent="0" pn="section-5-1">When a node has an ACP certificate (see <xref target="acp-certificates" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 6.2.1"/>) and is enabled to bring up the ACP (see <xref target="node-enable" format="default"/>), format="default" sectionFormat="of" derivedContent="Section 9.3.5"/>), it will create its ACP without any configuration as follows. For details, see <xref target="self-creation" format="default"/> format="default" sectionFormat="of" derivedContent="Section 6"/> and further following sections:
      </t>
      <ol type="1" spacing="compact">
        <li>The spacing="normal" indent="adaptive" start="1" pn="section-5-2">
        <li pn="section-5-2.1" derivedCounter="1.">The node creates a VRF instance, instance or a similar virtual context for the ACP.</li>
        <li>The
        <li pn="section-5-2.2" derivedCounter="2.">The node assigns its ULA IPv6 address (prefix) (see <xref target="addressing" format="default"/> format="default" sectionFormat="of" derivedContent="Section 6.11"/>), which is learned from the acp-node-name (see <xref target="domcert-acpinfo" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 6.2.2"/>) of its ACP certificate (see <xref target="acp-certificates" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 6.2.1"/>), to an ACP loopback interface (see <xref target="addressing" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 6.11"/>) and connects this interface into to the ACP VRF.</li>
        <li>The
        <li pn="section-5-2.3" derivedCounter="3.">The node establishes a list of candidate peer adjacencies and candidate channel types to try for the adjacency. This is automatic for all candidate link-local adjacencies, see adjacencies (see <xref target="discovery-grasp" format="default"/> format="default" sectionFormat="of" derivedContent="Section 6.4"/>) across all native interfaces (see <xref target="if-enable-auto" format="default"/>). format="default" sectionFormat="of" derivedContent="Section 9.3.4"/>). If a candidate peer is discovered via multiple interfaces, this will result in one adjacency per interface. If the ACP node has multiple interfaces connecting to the same subnet across which it is also operating as an L2 switch in the Data-Plane, data plane, it employs methods for ACP with L2 switching, see <xref target="acp-l2-switches" format="default"/>.</li>

        <li>For format="default" sectionFormat="of" derivedContent="Section 7"/>.</li>
        <li pn="section-5-2.4" derivedCounter="4.">For each entry in the candidate adjacency list, the node negotiates a secure tunnel using the candidate channel types.  See <xref target="channel-selection" format="default"/>.</li>

        <li>The format="default" sectionFormat="of" derivedContent="Section 6.6"/>.</li>
        <li pn="section-5-2.5" derivedCounter="5.">The node authenticates the peer node during secure channel setup and authorizes it to become part of the ACP according to <xref target="certcheck" format="default"/>.</li>

        <li>Unsuccessful format="default" sectionFormat="of" derivedContent="Section 6.2.3"/>.</li>
        <li pn="section-5-2.6" derivedCounter="6.">Unsuccessful authentication of a candidate peer results in throttled connection retries for as long as the candidate peer is discoverable. See <xref target="neighbor_verification" format="default"/>.</li>

        <li>Each format="default" sectionFormat="of" derivedContent="Section 6.7"/>.</li>
        <li pn="section-5-2.7" derivedCounter="7.">Each successfully established secure channel is mapped into to an ACP virtual interface, which is placed into the ACP VRF.  See <xref target="ACP-virtual-interfaces" format="default"/>.</li>

        <li>Each format="default" sectionFormat="of" derivedContent="Section 6.13.5.2"/>.</li>
        <li pn="section-5-2.8" derivedCounter="8.">Each node runs a lightweight routing protocol, see protocol (see <xref target="routing" format="default"/>, format="default" sectionFormat="of" derivedContent="Section 6.12"/>) to announce reachability of the ACP loopback address (or prefix) across the ACP.</li>

        <li>This
        <li pn="section-5-2.9" derivedCounter="9.">This completes the creation of the ACP with hop-by-hop secure tunnels, auto-addressing auto-addressing, and auto-routing. The node is now an ACP node with a running ACP.</li>
      </ol>
      <t>Note:
      <t indent="0" pn="section-5-3">Note:
      </t>
      <ul spacing="compact">
        <li>None spacing="normal" bare="false" empty="false" indent="3" pn="section-5-4">
        <li pn="section-5-4.1">None of the above operations (except the following explicit explicitly configured ones) are reflected in the configuration of the node.</li>
        <li>Non-ACP NMS ("Network Management Systems")
        <li anchor="sec5bt2" pn="section-5-4.2">Non-ACP network management systems (NMS) or SDN controllers have to be explicitly configured for connection into to the ACP.</li>
        <li>Additional
        <li pn="section-5-4.3">Additional candidate peer adjacencies for ACP connections across non-ACP Layer-3 Layer 3 clouds requires explicit configuration. See <xref target="remote-acp-neighbors" format="default"/>.</li> format="default" sectionFormat="of" derivedContent="Section 8.2"/>.</li>
      </ul>
      <t>The following figure
      <t indent="0" pn="section-5-5"><xref target="acp" format="default" sectionFormat="of" derivedContent="Figure 1"/> illustrates the ACP.</t>
      <figure anchor="acp">
        <name>ACP anchor="acp" align="left" suppress-title="false" pn="figure-1">
        <name slugifiedName="name-acp-vrf-and-secure-channels">ACP VRF and secure channels</name> Secure Channels</name>
        <artwork name="" type="" align="left" alt=""><![CDATA[ alt="" pn="section-5-6.1">
          ACP node Node 1                          ACP node Node 2
       ...................               ...................
secure .                 .   secure      .                 .  secure
channel:  +-----------+  :   channel     :  +-----------+  : channel
..--------| ACP VRF   |---------------------| ACP VRF   |---------..
       : / \         / \   <--routing-->   &lt;--routing--&gt;   / \         / \ :
       : \ /         \ /                   \ /         \ / :
..--------| Loopback loopback  |---------------------| Loopback loopback  |---------..
       :  | interface |  :               :  | interface |  :
       :  +-----------+  :               :  +-----------+  :
       :                 :               :                 :
       :   Data-Plane   Data Plane    :...............:   Data-Plane   Data Plane    :
       :                 :    link       :                 :
       :.................:               :.................:
        ]]></artwork>
</artwork>
      </figure>
      <t>The
      <t indent="0" pn="section-5-7">The resulting overlay network is normally based exclusively on hop-by-hop tunnels.  This is because addressing used on links is IPv6 link local link-local addressing, which does not require any prior set-up. setup.  In this way way, the ACP can be built even if there is no configuration on the node, or if the Data-Plane data plane has issues such as addressing or routing problems.</t>
    </section>
    <!-- overview -->
    <section anchor="self-creation" numbered="true" toc="default">
      <name>Self-Creation toc="include" removeInRFC="false" pn="section-6">
      <name slugifiedName="name-self-creation-of-an-autonom">Self-Creation of an Autonomic Control Plane (ACP) (Normative)</name>
      <t>This
      <t indent="0" pn="section-6-1">This section specifies the components and steps to set up an ACP. The ACP is automatically "self-creating", self-creating, which makes it "indestructible" against most changes to the Data-Plane, data plane, including misconfigurations of routing, addressing, NAT, firewall firewall, or any other traffic policy filters that would inadvertently or otherwise unavoidably would also impact the management plane traffic, such as the actual operator CLI command-line interface (CLI) session or controller NETCONF session through which the configuration changes to the Data-Plane data plane are executed.</t>
      <t>Physical
      <t indent="0" pn="section-6-2">Physical misconfiguration of wiring between ACP nodes will also not break the ACP: ACP. As long as there is a transitive physical path between ACP nodes, the ACP should be able to recover given that it automatically operates across all interfaces of the ACP nodes and automatically determines paths between them.</t>
      <t>Attacks
      <t indent="0" pn="section-6-3">Attacks against the network via incorrect routing or addressing information for the Data-Plane data plane will not impact the ACP. Even impaired ACP nodes will have a significantly reduced attack surface against malicious misconfiguration because only very limited ACP or interface up/down configuration can affect the ACP, and pending depending on their specific designs designs, these type types of attacks could also be eliminated. See more in <xref target="enabling-acp" format="default"/> format="default" sectionFormat="of" derivedContent="Section 9.3"/> and <xref target="security" format="default"/>.</t>
      <t>An format="default" sectionFormat="of" derivedContent="Section 11"/>.</t>
      <t indent="0" pn="section-6-4">An ACP node can be a router, switch, controller, NMS host, or any other IPv6 capable IPv6-capable node.  Initially, it MUST <bcp14>MUST</bcp14> have its ACP certificate, as well as an (empty) ACP Adjacency Table adjacency table (described in <xref target="adj-table" format="default"/>). format="default" sectionFormat="of" derivedContent="Section 6.3"/>).  It then can start to discover ACP neighbors and build the ACP.  This is described step by step in the following sections:</t> sections.</t>
      <section anchor="tls" numbered="true" toc="default">
        <name>Requirements toc="include" removeInRFC="false" pn="section-6.1">
        <name slugifiedName="name-requirements-for-the-use-of">Requirements for use the Use of Transport Layer Security (TLS)</name>
          <t>The
        <t indent="0" pn="section-6.1-1">The following requirements apply to TLS that is required or used by ACP components. Applicable ACP components include ACP certificate maintenance via EST, see EST (see <xref target="domcert-maint" format="default"/>, format="default" sectionFormat="of" derivedContent="Section 6.2.5"/>), TLS connections for Certificate Revocation List (CRL) CRL Distribution Point (CRLDP) or Online Certificate Status Protocol (OCSP) responder (if used, see <xref target="certcheck" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 6.2.3"/>), and ACP GRASP (see <xref target="GRASP-substrate" format="default"/>). format="default" sectionFormat="of" derivedContent="Section 6.9.2"/>). On ANI nodes nodes, these requirements also apply to BRSKI.</t>

          <t>TLS MUST
        <t indent="0" pn="section-6.1-2">TLS <bcp14>MUST</bcp14> comply with "<xref target="RFC7525" format="title" sectionFormat="of" derivedContent="Recommendations for Secure Use of Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS)"/>" <xref target="RFC7525" format="default"/> format="default" sectionFormat="of" derivedContent="RFC7525"/> except that TLS 1.2 (<xref ("<xref target="RFC5246" format="title" sectionFormat="of" derivedContent="The Transport Layer Security (TLS) Protocol Version 1.2"/>" <xref target="RFC5246" format="default"/>) format="default" sectionFormat="of" derivedContent="RFC5246"/>) is REQUIRED <bcp14>REQUIRED</bcp14> and that older versions of TLS MUST NOT <bcp14>MUST NOT</bcp14> be used.  TLS 1.3 (<xref ("<xref target="RFC8446" format="title" sectionFormat="of" derivedContent="The Transport Layer Security (TLS) Protocol Version 1.3"/>" <xref target="RFC8446" format="default"/>) SHOULD format="default" sectionFormat="of" derivedContent="RFC8446"/>) <bcp14>SHOULD</bcp14> be supported. The choice for TLS 1.2 as the lowest common denominator for the ACP is based on current the currently expected and most likely availability across the wide range of candidate ACP node types, potentially with non-agile operating system TCP/IP stacks.</t>

          <t>TLS MUST
        <t indent="0" pn="section-6.1-3">TLS <bcp14>MUST</bcp14> offer TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 and TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 and MUST NOT <bcp14>MUST NOT</bcp14> offer options with less than 256-bit symmetric key strength or hash strength of less than 384 bits.  When TLS 1.3 is  supported, TLS_AES_256_GCM_SHA384 MUST <bcp14>MUST</bcp14> be offered and TLS_CHACHA20_POLY1305_SHA256 MAY <bcp14>MAY</bcp14> be offered.</t>

          <t>TLS MUST
        <t indent="0" pn="section-6.1-4">TLS <bcp14>MUST</bcp14> also include the "Supported Elliptic Curves" extension, and it MUST <bcp14>MUST</bcp14> support the NIST P-256 (secp256r1(22)) and P-384 (secp384r1(24)) curves "<xref target="RFC8422" format="title" sectionFormat="of" derivedContent="Elliptic Curve Cryptography (ECC) Cipher Suites for Transport Layer Security (TLS) Versions 1.2 and Earlier"/>" <xref target="RFC8422" format="default"/>. format="default" sectionFormat="of" derivedContent="RFC8422"/>.  In addition, TLS 1.2 clients SHOULD <bcp14>SHOULD</bcp14> send an ec_point_format extension with a single element, "uncompressed".</t>
      </section>
      <section anchor="domcert" numbered="true" toc="default">
        <name>ACP toc="include" removeInRFC="false" pn="section-6.2">
        <name slugifiedName="name-acp-domain-certificate-and-">ACP Domain, Certificate Certificate, and Network</name>
        <t>The
        <t indent="0" pn="section-6.2-1">The ACP relies on group security.  An ACP domain is a group of nodes that trust
each other to participate in ACP operations such as creating ACP secure channels
in an autonomous autonomous, peer-to-peer fashion between ACP domain members via protocols such as IPsec.
To authenticate and authorize another ACP member node with access to the ACP Domain, domain, each ACP member requires
keying material: An an ACP node MUST <bcp14>MUST</bcp14> have a Local Device IDentity (LDevID) certificate,
henceforth called the ACP an LDevID certificate
and information about one or more Trust Anchor (TA) TAs
as required for the ACP domain membership check (<xref target="certcheck" format="default"/>).</t>
        <t>Manual format="default" sectionFormat="of" derivedContent="Section 6.2.3"/>).</t>
        <t indent="0" pn="section-6.2-2">Manual keying via shared secrets is not usable for an ACP domain because it would require a single shared secret across all current and future ACP domain members to meet the expectation of autonomous, peer-to-peer establishment of ACP secure channels between any ACP domain members. Such a single shared secret would be an inacceptable unacceptable security weakness. Asymmetric keying material (public keys) without certificates does not provide the mechanisms mechanism to authenticate ACP domain membership in an autonomous, peer-to-peer fashion for current and future ACP domain members.</t>
        <t>The
        <t indent="0" pn="section-6.2-3">The LDevID certificate is henceforth called the ACP certificate. The TA is the Certification Authority (CA) CA root certificate of the ACP domain.</t>
        <t>The
        <t indent="0" pn="section-6.2-4">The ACP does not mandate specific mechanisms by which this keying material is provisioned into the ACP node. It only requires that the certificate to comply with <xref target="acp-certificates" format="default"/>, format="default" sectionFormat="of" derivedContent="Section 6.2.1"/>, specifically to that it have the acp-node-name as specified in <xref target="domcert-acpinfo" format="default"/> format="default" sectionFormat="of" derivedContent="Section 6.2.2"/> in its domain certificate as well as those of candidate ACP peers.  See <xref target="bootstrap" format="default"/> format="default" sectionFormat="of" derivedContent="Appendix A.2"/> for more information about enrollment or provisioning options.</t>

        <t>This
        <t indent="0" pn="section-6.2-5">This document uses the term ACP in many places where the Autonomic Networking reference documents <xref target="RFC7575" format="default"/> format="default" sectionFormat="of" derivedContent="RFC7575"/> and <xref target="I-D.ietf-anima-reference-model" format="default"/> target="RFC8993" format="default" sectionFormat="of" derivedContent="RFC8993"/> use the word autonomic.  This is done because those reference documents consider (only) fully autonomic networks Autonomic Networks and nodes, but the support of ACP does not require the support for other components of autonomic networks Autonomic Networks except for relying the reliance on GRASP and the providing of security and transport for GRASP.  Therefore, the word autonomic might be misleading to operators interested in only the ACP.</t>
        <t><xref
        <t indent="0" pn="section-6.2-6"><xref target="RFC7575" format="default"/> format="default" sectionFormat="of" derivedContent="RFC7575"/> defines the term "Autonomic Domain" "autonomic domain" as a collection of autonomic nodes.  ACP nodes do not need to be fully autonomic, but when they are, then the ACP domain is an autonomic domain.  Likewise, <xref target="I-D.ietf-anima-reference-model" format="default"/> target="RFC8993" format="default" sectionFormat="of" derivedContent="RFC8993"/> defines the term "Domain Certificate" "domain certificate" as the certificate used in an autonomic domain.  The ACP certificate is that domain certificate when ACP nodes are (fully) autonomic nodes.  Finally, this document uses the term ACP network to refer to the network created by active ACP nodes in an ACP domain.  The ACP network itself can extend beyond ACP nodes through the mechanisms described in <xref target="ACPconnect" format="default"/>.</t> format="default" sectionFormat="of" derivedContent="Section 8.1"/>.</t>
        <section anchor="acp-certificates" numbered="true" toc="default">
          <name>ACP toc="include" removeInRFC="false" pn="section-6.2.1">
          <name slugifiedName="name-acp-certificates">ACP Certificates</name>
          <t>ACP
          <t indent="0" pn="section-6.2.1-1">ACP certificates MUST <bcp14>MUST</bcp14> be <xref target="RFC5280" format="default"/> format="default" sectionFormat="of" derivedContent="RFC5280"/> compliant X.509 v3 (<xref <xref target="X.509" format="default"/>) format="default" sectionFormat="of" derivedContent="X.509"/> certificates.</t>
          <t>ACP
          <t indent="0" pn="section-6.2.1-2">ACP nodes MUST <bcp14>MUST</bcp14> support handling ACP certificates, TA certificates certificates, and certificate chain certificates (henceforth just called certificates in this section) with RSA public keys and certificates with Elliptic Curve Cryptography (ECC) public keys.</t>

          <t>ACP
          <t indent="0" pn="section-6.2.1-3">ACP nodes MUST NOT <bcp14>MUST NOT</bcp14> support certificates with RSA public keys of less than a 2048-bit modulus or curves with group order of less than 256-bit. 256 bits. They MUST <bcp14>MUST</bcp14> support certificates with RSA public keys with 2048-bit modulus and MAY <bcp14>MAY</bcp14> support longer RSA keys. They MUST <bcp14>MUST</bcp14> support certificates with ECC public keys using NIST P-256 curves and SHOULD <bcp14>SHOULD</bcp14> support P-384 and P-521 curves.</t>

          <t>ACP
          <t indent="0" pn="section-6.2.1-4">ACP nodes MUST NOT <bcp14>MUST NOT</bcp14> support certificates with RSA public keys whose
          modulus is less than 2048 bits, or certificates whose ECC public keys
          are in groups whose order is less than 256-bits. 256 bits.  RSA signing
          certificates with 2048-bit public keys MUST <bcp14>MUST</bcp14> be supported, and such
          certificates with longer public keys MAY <bcp14>MAY</bcp14> be supported.  ECDSA
          certificates using the NIST P-256 curve MUST <bcp14>MUST</bcp14> be supported, and such
          certificates using the P-384 and P-521 curves SHOULD <bcp14>SHOULD</bcp14> be supported.</t>

          <t>ACP
          <t indent="0" pn="section-6.2.1-5">ACP nodes MUST <bcp14>MUST</bcp14> support RSA certificates that are signed by RSA
          signatures over the SHA-256 digest of the contents, contents and SHOULD <bcp14>SHOULD</bcp14>
          additionally support SHA-384 and SHA-512 digests in such signatures.
          The same requirements for digest usage in certificate signatures apply to ECDSA Elliptic Curve Digital Signature Algorithm (ECDSA)
          certificates, and additionally, ACP nodes MUST <bcp14>MUST</bcp14> support ECDSA
          signatures on ECDSA certificates.</t>

          <t>The
          <t indent="0" pn="section-6.2.1-6">The ACP certificate SHOULD <bcp14>SHOULD</bcp14> use an RSA key and an RSA signature when the ACP certificate is intended to be used not only for ACP authentication but also for other purposes. The ACP certificate MAY <bcp14>MAY</bcp14> use an ECC key and an ECDSA signature if the ACP certificate is only used for ACP and ANI authentication and authorization.</t>

          <t>Any
          <t indent="0" pn="section-6.2.1-7">Any secure channel protocols used for the ACP as specified in this document or extensions of this document MUST <bcp14>MUST</bcp14> therefore support authentication (e.g. signing) (e.g., signing), starting with these type types of certificates. See <xref target="RFC8422" format="default"/> format="default" sectionFormat="of" derivedContent="RFC8422"/> for more information.</t>

          <t>The
          <t indent="0" pn="section-6.2.1-8">The reason for these choices are as follows: As as of 2020, RSA is still more widely used than ECC, therefore the MUST <bcp14>MUST</bcp14>-level requirements for RSA. ECC offers equivalent security at (logarithmically) shorter key lengths (see <xref target="RFC8422" format="default"/>). format="default" sectionFormat="of" derivedContent="RFC8422"/>). This can be beneficial especially in the presence of constrained bandwidth or constrained nodes in an ACP/ANI network. Some ACP functions such as GRASP peer-2-peer peer-to-peer across the ACP require end-to-end/any-to-any authentication/authorization, authentication and authorization, therefore ECC can only reliably be used in the ACP when it MUST <bcp14>MUST</bcp14> be supported on all ACP nodes. RSA signatures are mandatory to be supported also for ECC certificates because the CAs themselves may not support ECC yet.</t>

          <t>The
          <t indent="0" pn="section-6.2.1-9">The ACP certificate SHOULD <bcp14>SHOULD</bcp14> be used for any authentication between nodes with ACP
domain certificates (ACP nodes and NOC nodes) where a required authorization condition is ACP domain membership, such as ACP node to NOC/OAM end-to-end security and ASA to ASA end-to-end security.
<xref target="certcheck" format="default"/> format="default" sectionFormat="of" derivedContent="Section 6.2.3"/> defines this "ACP domain membership check".
The uses of this check that are standardized in this document are for the establishment of
hop-by-hop ACP secure channels (<xref target="neighbor_verification" format="default"/>) target="associations" format="default" sectionFormat="of" derivedContent="Section 6.8"/>) and for ACP GRASP (<xref target="GRASP-substrate" format="default"/>) end-to-end format="default" sectionFormat="of" derivedContent="Section 6.9.2"/>) end to end via TLS.</t>

          <t>The
          <t indent="0" pn="section-6.2.1-10">The ACP domain membership check requires a minimum amount number of elements in a certificate as described in <xref target="certcheck" format="default"/>. format="default" sectionFormat="of" derivedContent="Section 6.2.3"/>. The identity of a node in the ACP is carried via the acp-node-name as defined in <xref target="domcert-acpinfo" format="default"/>.</t>

<t>To format="default" sectionFormat="of" derivedContent="Section 6.2.2"/>.</t>
          <t indent="0" pn="section-6.2.1-11">To support ECDH Elliptic Curve Diffie-Hellman (ECDH) directly with the key in the ACP certificate,
ACP certificates with ECC keys need to indicate to be Elliptic Curve Diffie-Hellman
capable (ECDH): If that they are ECDH
capable: if the X.509v3 X.509 v3 keyUsage extension is present, the keyAgreement bit
must then be set. Note that this option is not required for any of the
required ciphersuites in this document and may not be supported by all CA.</t>

          <t>Any CAs.</t>
          <t indent="0" pn="section-6.2.1-12">Any other fields of the ACP certificate are to be populated as required by <xref target="RFC5280" format="default"/>: format="default" sectionFormat="of" derivedContent="RFC5280"/>. As long as they are compliant with <xref target="RFC5280" format="default"/>, format="default" sectionFormat="of" derivedContent="RFC5280"/>, any other field of an ACP certificate can be set as desired by the operator of the ACP domain through the appropriate ACP registrar/ACP registrar and/or ACP CA procedures. For example, other fields may be required for other purposes other than those that the ACP certificate is intended to be used for (such as elements of a SubjectName).</t>

          <t>For
          <t indent="0" pn="section-6.2.1-13">For further certificate details, ACP certificates may follow the recommendations from <xref target="CABFORUM" format="default"/>.</t>

          <t>For format="default" sectionFormat="of" derivedContent="CABFORUM"/>.</t>
          <t indent="0" pn="section-6.2.1-14">For diagnostic and other operational purposes, it is beneficial
	  to copy the device identifying device-identifying fields of the node's IDevID
	  certificate into the ACP certificate, such as the <xref target="X.520" format="default"/>, section 6.2.9
"serialNumber" attribute
(<xref target="X.520" format="default" sectionFormat="of" derivedContent="X.520"/>, Section 6.2.9)
in the subject field distinguished name encoding. Note
	  that this is not the certificate serial number. serial-number.  See also <xref target="I-D.ietf-anima-bootstrapping-keyinfra" format="default"/> section 2.3.1. target="RFC8995" sectionFormat="comma" section="2.3.1" format="default" derivedLink="https://rfc-editor.org/rfc/rfc8995#section-2.3.1" derivedContent="RFC8995"/>. This can be done done, for example example, if it would be acceptable for the device's "serialNumber" to be signaled via the Link Layer Discovery Protocol (LLDP, <xref target="LLDP" format="default"/>) because format="default" sectionFormat="of" derivedContent="LLDP"/> because, like LLDP signaled LLDP-signaled information, the ACP certificate information can be retrieved by neighboring nodes without further authentication and can be used either for beneficial diagnostics or for malicious attacks. Retrieval of the ACP certificate is possible via a (failing) attempt to set up an ACP secure channel, and the "serialNumber" usually contains device type information that may help to faster more quickly determine working exploits/attacks against the device.</t>

          <t>Note
          <t indent="0" pn="section-6.2.1-15">Note that there is no intention to constrain authorization within the ACP or autonomic networks Autonomic Networks using the ACP to just the ACP domain membership check as defined in this document. It can be extended or modified with additional requirements. Such future authorizations can use and require additional elements in certificates or policies or even additional certificates. See <xref target="domcert-maint" format="default" sectionFormat="of" derivedContent="Section 6.2.5"/> for the additional check against the id-kp-cmcRA <xref target="RFC6402" format="default"/> extended key usage attribute (<xref target="domcert-maint" format="default"/>) ("<xref target="RFC6402" format="title" sectionFormat="of" derivedContent="Certificate Management over CMS (CMC) Updates"/>" <xref target="RFC6402" format="default" sectionFormat="of" derivedContent="RFC6402"/>), and for possible future extensions,  see <xref target="role-assignments" format="default"/>.</t> format="default" sectionFormat="of" derivedContent="Appendix A.9.5"/> for possible future extensions.</t>
        </section>
        <section anchor="domcert-acpinfo" numbered="true" toc="default">
          <name>ACP toc="include" removeInRFC="false" pn="section-6.2.2">
          <name slugifiedName="name-acp-certificate-acpnodename">ACP Certificate AcpNodeName</name>
          <?rfc needLines="20" ?>
          <figure anchor="acp-dominfo-abnf">
            <name>ACP anchor="acp-dominfo-abnf" align="left" suppress-title="false" pn="figure-2">
            <name slugifiedName="name-acp-node-name-abnf">ACP Node Name ABNF</name>
            <artwork
            <sourcecode name="" type="" align="left" alt=""><![CDATA[ type="abnf" markers="false" pn="section-6.2.2-1.1">
  acp-node-name = local-part "@" acp-domain-name
  local-part = [ acp-address ] [ "+" rsub extensions ]
  acp-address = 32HEXDIG | / "0" ; HEXDIG as of RFC5234 section [RFC5234], Appendix B.1
  rsub = [ <subdomain> &lt;subdomain&gt; ] ; <subdomain> &lt;subdomain&gt; as of RFC1034, section [RFC1034], Section 3.5
  acp-domain-name = ; <domain> &lt;domain&gt; ; as of RFC 1034, section [RFC1034], Section 3.5
  extensions = *( "+" extension )
  extension  = 1*etext  ; future standard definition.
  etext      = ALPHA / DIGIT /  ; Printable US-ASCII
               "!" / "#" / "$" / "%" / "&" "&amp;" / "'" /
               "*" / "-" / "/" / "=" / "?" / "^" /
               "_" / "`" / "{" / "|" / "}" / "~"

  routing-subdomain = [ rsub "." ] acp-domain-name

  Example:
    given
</sourcecode>
          </figure>
          <t indent="0" pn="section-6.2.2-2">Example:</t>
          <t indent="0" pn="section-6.2.2-3">Given an ACP address of fd89:b714:f3db:0:200:0:6400:0000
    and fd89:b714:f3db:0:200:0:6400:0000,
    an ACP domain-name domain name of acp.example.com acp.example.com,
    and an rsub extenstion extension of area51.research area51.research, then this results in: in the following:</t>
          <artwork align="left" pn="section-6.2.2-4">
  acp-node-name      = fd89b714f3db00000200000064000000
                       +area51.research@acp.example.com
  acp-domain-name    = acp.example.com
  routing-subdomain  = area51.research.acp.example.com
]]></artwork>
          </figure>
          <t>acp-node-name
</artwork>
          <t indent="0" pn="section-6.2.2-5">The acp-node-name in above <xref target="acp-dominfo-abnf" format="default"/> format="default" sectionFormat="of" derivedContent="Figure 2"/> is the ABNF (<xref target="RFC5234" format="default"/>) definition ("<xref target="RFC5234" format="title" sectionFormat="of" derivedContent="Augmented BNF for Syntax Specifications: ABNF"/>" <xref target="RFC5234" format="default" sectionFormat="of" derivedContent="RFC5234"/>) of the ACP Node Name. An ACP certificate MUST <bcp14>MUST</bcp14> carry this information. It MUST be encoded as a subjectAltName / <bcp14>MUST</bcp14> contain an otherName / field in the X.509 Subject Alternative Name extension, and the otherName <bcp14>MUST</bcp14> contain an AcpNodeName as described in <xref target="asn1" format="default"/>.</t>
          <t>Nodes target="domcert-acpinfo" format="default" sectionFormat="of" derivedContent="Section 6.2.2"/>.</t>
          <t indent="0" pn="section-6.2.2-6">Nodes complying with this specification MUST <bcp14>MUST</bcp14> be able to receive their ACP address through the domain certificate, in which case their own ACP certificate MUST <bcp14>MUST</bcp14> have a 32HEXDIG acp-address field. Acp-address The acp-address field is case insensitive because ABNF HEXDIG is. It is recommended to encode acp-address with lower case lowercase letters. Nodes complying with this specification MUST <bcp14>MUST</bcp14> also be able to authenticate nodes as ACP domain members or ACP secure channel peers when they have a 0-value zero-value acp-address field and as ACP domain members (but not as ACP secure channel peers) when the acp-address field is omitted from their AcpNodeName.  See <xref target="certcheck" format="default"/>.</t>
          <t>acp-domain-name format="default" sectionFormat="of" derivedContent="Section 6.2.3"/>.</t>
          <t indent="0" pn="section-6.2.2-7">The acp-domain-name is used to indicate the ACP Domain domain across which ACP nodes authenticate and authorize each other, for example example, to build ACP secure channels to each other, see <xref target="certcheck" format="default"/>. format="default" sectionFormat="of" derivedContent="Section 6.2.3"/>. The acp-domain-name SHOULD <bcp14>SHOULD</bcp14> be the FQDN of an Internet domain owned by the network administration of the ACP and ideally reserved to only be used for the ACP. In this specification specification, it serves to be as a name for the ACP that ideally is globally unique.  When acp-domain-name is a globally unique name, collision of ACP addresses across different ACP domains can only happen due to ULA hash collisions (see <xref target="scheme" format="default"/>). format="default" sectionFormat="of" derivedContent="Section 6.11.2"/>). Using different acp-domain-names, operators can distinguish multiple ACP ACPs even when using the same TA.</t>
          <t>To
          <t indent="0" pn="section-6.2.2-8">To keep the encoding simple, there is no consideration for internationalized acp-domain-names. The acp-node-name is not intended for end user end-user consumption. There is no protection against an operator to pick picking any domain name for an ACP whether or not the operator can claim to own the domain name. Instead, the domain name only serves as a hash seed for the ULA and for diagnostics to for the operator. Therefore, any operator owning only an internationalized domain name should be able to pick an equivalently unique 7-bit ASCII acp-domain-name string representing the internationalized domain name.</t>
          <t>"routing-subdomain"
          <t indent="0" pn="section-6.2.2-9">The routing-subdomain is a string that can be constructed from the acp-node-name, and it is used in the hash-creation hash creation of the ULA (see below). <xref target="scheme" format="default" sectionFormat="of" derivedContent="Section 6.11.2"/>).  The presence of the "rsub" rsub component allows a single ACP domain to employ multiple /48 ULA prefixes.  See <xref target="domain-usage" format="default"/> format="default" sectionFormat="of" derivedContent="Appendix A.6"/> for example use-cases.</t>
          <t>The use cases.</t>
          <t indent="0" pn="section-6.2.2-10">The optional "extensions" extensions field is used for future standardized extensions to this specification.  It MUST <bcp14>MUST</bcp14> be ignored if present and not understood.</t>
          <t>The
          <t indent="0" pn="section-6.2.2-11">The following points explain and justify the encoding choices described:
          </t>
          <ol type="1" spacing="compact">
            <li>
              <t>Formatting spacing="normal" indent="adaptive" start="1" pn="section-6.2.2-12">
            <li pn="section-6.2.2-12.1" derivedCounter="1.">
              <t indent="0" pn="section-6.2.2-12.1.1">Formatting notes:
              </t>
              <ol type="1.%d" spacing="compact">
                <li>"rsub" spacing="normal" indent="adaptive" start="1" pn="section-6.2.2-12.1.2">
                <li pn="section-6.2.2-12.1.2.1" derivedCounter="1.1">The rsub component needs to be in the "local-part": If local-part: if the format just had routing-subdomain as the domain part of the acp-node-name, rsub and acp-domain-name could not be separated from each other to determine in the ACP domain membership check which part is the acp-domain-name and which is solely for creating a different ULA prefix.</li>
                <li>If
                <li pn="section-6.2.2-12.1.2.2" derivedCounter="1.2">If both "acp-address" acp-address and "rsub" rsub are omitted from AcpNodeName, the "local-part" local-part will have the format "++extension(s)". The two plus characters are necessary so the node can unambiguously parse that both "acp-address" acp-address and "rsub" rsub are omitted.</li>
              </ol>
            </li>
            <li>
              <t>The
            <li pn="section-6.2.2-12.2" derivedCounter="2.">
              <t indent="0" pn="section-6.2.2-12.2.1">The encoding of the ACP domain name and ACP address as described in this section is used for the following reasons:

              </t>
              <ol type="2.%d" spacing="compact">
                <li>The spacing="normal" indent="adaptive" start="1" pn="section-6.2.2-12.2.2">
                <li pn="section-6.2.2-12.2.2.1" derivedCounter="2.1">The acp-node-name is the identifier of a node's ACP. It includes the necessary components to identify a node's ACP both from within the ACP as well as from the outside of the ACP.</li>
                <li>For
                <li pn="section-6.2.2-12.2.2.2" derivedCounter="2.2">For manual and/or automated diagnostics and backend management of devices and ACPs, it is necessary to have an easily human readable human-readable and software parsed software-parsable standard, single string representation of the information in the acp-node-name. For example, inventory or other backend systems can always identify an entity by one unique string field but not by a combination of multiple fields, which would be necessary if there was were no single string representation.</li>
                <li>If
                <li pn="section-6.2.2-12.2.2.3" derivedCounter="2.3">If the encoding was not that of such a string, it would be necessary to define a second standard encoding to provide this format (standard string encoding) for operator consumption.</li>
                <li>Addresses
                <li pn="section-6.2.2-12.2.2.4" derivedCounter="2.4">Addresses of the form &lt;local&gt;@&lt;domain&gt; have become the preferred format for identifiers of entities in many systems, including the majority of user identification identifiers in web or mobile applications such as multi-domain single-sign-on systems.</li>
              </ol>
            </li>
            <li>
              <t>Compatibilities:
            <li pn="section-6.2.2-12.3" derivedCounter="3.">
              <t indent="0" pn="section-6.2.2-12.3.1">Compatibilities:

              </t>
              <ol type="3.%d" spacing="compact">
                <li>It spacing="normal" indent="adaptive" start="1" pn="section-6.2.2-12.3.2">
                <li pn="section-6.2.2-12.3.2.1" derivedCounter="3.1">It should be possible to use the ACP certificate as an LDevID certificate on the system for other uses beside besides the ACP.  Therefore, the information element required for the ACP should be encoded so that it minimizes the possibility of creating incompatibilities with such other such uses. The attributes of the subject field field, for example example, are often used in non-ACP applications and should therefore should not be occupied by new ACP values.</li>
                <li>The
                <li pn="section-6.2.2-12.3.2.2" derivedCounter="3.2">The element should not require additional ASN.1 en/decoding, encoding and/or decoding because libraries to access for accessing certificate information information, especially for embedded devices devices, may not support extended ASN.1 decoding beyond predefined, mandatory fields. subjectAltName / otherName is already used with a single string parameter for several otherNames (see "<xref target="RFC6120" format="title" sectionFormat="of" derivedContent="Extensible Messaging and Presence Protocol (XMPP): Core"/>" <xref target="RFC3920" format="default"/>, target="RFC6120" format="default" sectionFormat="of" derivedContent="RFC6120"/>, "<xref target="RFC7585" format="title" sectionFormat="of" derivedContent="Dynamic Peer Discovery for RADIUS/TLS and RADIUS/DTLS Based on the Network Access Identifier (NAI)"/>" <xref target="RFC7585" format="default"/>, format="default" sectionFormat="of" derivedContent="RFC7585"/>, "<xref target="RFC4985" format="title" sectionFormat="of" derivedContent="Internet X.509 Public Key Infrastructure Subject Alternative Name for Expression of Service Name"/>" <xref target="RFC4985" format="default"/>, format="default" sectionFormat="of" derivedContent="RFC4985"/>, "<xref target="RFC8398" format="title" sectionFormat="of" derivedContent="Internationalized Email Addresses in X.509 Certificates"/>" <xref target="RFC8398" format="default"/>).</li>
                <li>The format="default" sectionFormat="of" derivedContent="RFC8398"/>).</li>
                <li pn="section-6.2.2-12.3.2.3" derivedCounter="3.3">The element required for the ACP should minimize the risk of being misinterpreted by other uses of the LDevID certificate.  It also must not be misinterpreted to actually be as an email address, hence the use of the otherName / rfc822Name option in the certificate would be inappropriate.</li>
              </ol>
            </li>
          </ol>
          <t>See section 4.2.1.6 of
          <t indent="0" pn="section-6.2.2-13">See <xref target="RFC5280" format="default"/> sectionFormat="of" section="4.2.1.6" format="default" derivedLink="https://rfc-editor.org/rfc/rfc5280#section-4.2.1.6" derivedContent="RFC5280"/> for details on the subjectAltName field.</t>
          <section anchor="asn1" numbered="true" toc="default">
            <name>AcpNodeName toc="include" removeInRFC="false" pn="section-6.2.2.1">
            <name slugifiedName="name-acpnodename-asn1-module">AcpNodeName ASN.1 Module</name>
            <t>The
            <t indent="0" pn="section-6.2.2.1-1">The following ASN.1 module normatively specifies the AcpNodeName structure.
This specification uses the ASN.1 definitions from "<xref target="RFC5912" format="title" sectionFormat="of" derivedContent="New ASN.1 Modules for the Public Key Infrastructure Using X.509 (PKIX)"/>" <xref target="RFC5912" format="default"/> format="default" sectionFormat="of" derivedContent="RFC5912"/>
with the 2002 ASN.1 notation used in that document.  <xref target="RFC5912" format="default"/> format="default" sectionFormat="of" derivedContent="RFC5912"/>
updates normative documents using older ASN.1 notation.</t>
            <figure>
              <artwork name="" type=""
            <figure align="left" alt=""><![CDATA[ suppress-title="false" pn="figure-3">
              <name slugifiedName="name-acpnodename-asn1-module-2">AcpNodeName ASN.1 Module</name>
              <sourcecode name="" type="asn.1" markers="false" pn="section-6.2.2.1-2.1">
ANIMA-ACP-2020
  { iso(1) identified-organization(3) dod(6)
    internet(1) security(5) mechanisms(5) pkix(7) id-mod(0)
    id-mod-anima-acpnodename-2020(IANA1)
    id-mod-anima-acpnodename-2020(97) }

DEFINITIONS IMPLICIT TAGS ::=
BEGIN

IMPORTS
  OTHER-NAME
  FROM PKIX1Implicit-2009
    { iso(1) identified-organization(3) dod(6) internet(1)
      security(5) mechanisms(5) pkix(7) id-mod(0)
      id-mod-pkix1-implicit-02(59) }

  id-pkix
  FROM PKIX1Explicit-2009
    { iso(1) identified-organization(3) dod(6) internet(1)
      security(5) mechanisms(5) pkix(7) id-mod(0)
      id-mod-pkix1-explicit-02(51) } ;

  id-on OBJECT IDENTIFIER ::= { id-pkix 8 }

  AcpNodeNameOtherNames OTHER-NAME ::= { on-AcpNodeName, ... }

  on-AcpNodeName OTHER-NAME ::= {
      AcpNodeName IDENTIFIED BY id-on-AcpNodeName
  }

  id-on-AcpNodeName OBJECT IDENTIFIER ::= { id-on IANA2 10 }

  AcpNodeName ::= IA5String (SIZE (1..MAX))
   -- AcpNodeName as specified in this document carries the
   -- acp-node-name as specified in the ABNF in Section 6.1.2 6.2.2

END
]]></artwork>
</sourcecode>
            </figure>
          </section>
        </section>
        <!-- domcert-acpinfo -->
        <section anchor="certcheck" numbered="true" toc="default">
          <name>ACP domain membership check</name>
          <t>The toc="include" removeInRFC="false" pn="section-6.2.3">
          <name slugifiedName="name-acp-domain-membership-check">ACP Domain Membership Check</name>
          <t indent="0" pn="section-6.2.3-1">The following points constitute the ACP domain membership check of a candidate peer via its certificate:
          </t>
          <dl spacing="compact">
            <dt>1: </dt>
            <dd>The
          <ol spacing="normal" group="acp" start="1" indent="adaptive" type="1" pn="section-6.2.3-2">
            <li anchor="step1" pn="section-6.2.3-2.1" derivedCounter="1.">The peer has proved ownership of the private key associated
	    with the certificate's public key. This check is performed by the
	    security association protocol used, for example example, Section <xref target="RFC7296" format="default"/>, section 2.15.</dd>
            <dt>2: </dt>
            <dd>The section="2.15" sectionFormat="bare" format="default" derivedLink="https://rfc-editor.org/rfc/rfc7296#section-2.15" derivedContent="RFC7296"/> of <xref target="RFC7296" format="default" sectionFormat="of" derivedContent="RFC7296">"Internet Key Exchange Protocol Version 2 (IKEv2)"</xref>.</li>
            <li anchor="step2" pn="section-6.2.3-2.2" derivedCounter="2.">The peer's certificate passes certificate path validation as
	    defined in <xref target="RFC5280" format="default"/>, section 6 sectionFormat="comma" section="6" format="default" derivedLink="https://rfc-editor.org/rfc/rfc5280#section-6" derivedContent="RFC5280"/>, against one of the TA TAs associated with the ACP node's ACP certificate (see <xref target="trust-anchors" format="default"/> below). format="default" sectionFormat="of" derivedContent="Section 6.2.4"/>). This includes verification of the validity (lifetime) of the certificates in the path.</dd>
            <dt>3: </dt>
            <dd>If path.</li>
            <li anchor="step3" pn="section-6.2.3-2.3" derivedCounter="3.">
              <t indent="0" pn="section-6.2.3-2.3.1">If the peer's certificate indicates a Certificate Revocation List (CRL) Distribution Point (CRLDP) CRLDP
             (<xref target="RFC5280" format="default"/>, section 4.2.1.13) sectionFormat="comma" section="4.2.1.13" format="default" derivedLink="https://rfc-editor.org/rfc/rfc5280#section-4.2.1.13" derivedContent="RFC5280"/>) or Online Certificate Status Protocol (OCSP) OCSP responder
             (<xref target="RFC5280" format="default"/>, section 4.2.2.1), sectionFormat="comma" section="4.2.2.1" format="default" derivedLink="https://rfc-editor.org/rfc/rfc5280#section-4.2.2.1" derivedContent="RFC5280"/>), then the peer's certificate MUST <bcp14>MUST</bcp14> be valid according to those
             mechanisms when they are available: An an OCSP check for the peer's certificate across the ACP must succeed succeed, or the peer peer's certificate must not be listed in the CRL retrieved from the CRLDP. These mechanisms are not available
             when the ACP node has no ACP or non-ACP connectivity to retrieve a current CRL
             or has no access an OCSP responder responder, and the security association protocol itself has also has no way to communicate the CRL or OCSP check.</dd>
            <dt>   </dt>
            <dd>Retries check.</t>
              <t indent="0" pn="section-6.2.3-2.3.2">Retries to learn revocation via OCSP/CRL SHOULD OCSP or CRL <bcp14>SHOULD</bcp14> be made using the same backoff as described in <xref target="neighbor_verification" format="default"/>. format="default" sectionFormat="of" derivedContent="Section 6.7"/>. If and when the ACP node then learns that an ACP peer's certificate is invalid for which rule 3 <xref target="step3" format="none" sectionFormat="of" derivedContent="">Rule 3</xref> had to be skipped during ACP secure channel establishment, then the ACP secure channel to that peer MUST <bcp14>MUST</bcp14> be closed even if this peer is the only connectivity to access CRL/OCSP. This applies (of course) to all ACP secure channels to this peer if there are multiple.  The ACP secure channel connection MUST <bcp14>MUST</bcp14> be retried periodically to support the case that the neighbor acquires a new, valid certificate.</dd>
            <dt>4: </dt>
            <dd>The certificate.</t>
            </li>
            <li anchor="step4" pn="section-6.2.3-2.4" derivedCounter="4.">The peer's certificate has a syntactically valid acp-node-name field field,
             and the acp-domain-name in that peer's acp-node-name is the same as in this ACP node's certificate (lowercase normalized).</dd>
          </dl>
          <t>When normalized).</li>
          </ol>
          <t indent="0" pn="section-6.2.3-3">When checking a candidate peer's certificate for the purpose of establishing an ACP secure channel,
         one additional check is performed:
          </t>
          <dl spacing="compact">
            <dt>5: </dt>
            <dd>The
          <ol group="acp" start="5" indent="adaptive" spacing="normal" type="1" pn="section-6.2.3-4">
<li anchor="step5" pn="section-6.2.3-4.1" derivedCounter="5.">The acp-address field of the candidate peer certificate's AcpNodeName is not omitted but is either 32HEXDIG or 0, according to <xref target="acp-dominfo-abnf" format="default"/>.</dd>
          </dl>
          <t>Technically, format="default" sectionFormat="of" derivedContent="Figure 2"/>.</li>
          </ol>
          <t indent="0" pn="section-6.2.3-5">Technically, ACP secure channels can only be built with nodes that
         have an acp-address. Rule 5 <xref target="step5" format="none" sectionFormat="of" derivedContent="">Rule 5</xref> ensures that this is taken into account
         during ACP domain membership check.</t>
          <t>Nodes
          <t indent="0" pn="section-6.2.3-6">Nodes with an omitted acp-address field can only use their ACP domain
         certificate for non-ACP-secure non-ACP secure channel authentication purposes.
         This includes includes, for example example, NMS type nodes permitted to communicate
         into the ACP via <xref target="ACPconnect" format="default">ACP format="default" sectionFormat="of" derivedContent="Section 8.1">ACP connect</xref></t>
          <t>
          <t indent="0" pn="section-6.2.3-7"> The special value 0 "0" in an ACP certificates certificate's acp-address field
          is used for nodes that can and should determine their ACP address
          through other mechanisms other than learning it through the acp-address
          field in their ACP certificate. These ACP nodes are permitted
          to establish ACP secure channels. Mechanisms for those nodes to
          determine their ACP address are outside the scope of this
          specification, but this option is defined here so that any
          ACP nodes can build ACP secure channels to them according to Rule 5.</t>

          <t>The <xref target="step5" format="none" sectionFormat="of" derivedContent="">Rule 5.</xref></t>
          <t indent="0" pn="section-6.2.3-8">The optional rsub field of the AcpNodeName is not relevant to the
          ACP domain membership check because it only serves to structure routing and
          addressing within an ACP but not to segment mutual authentication/authorization authentication and authorization
          (hence the name "routing subdomain").</t>

          <t>In
          <t indent="0" pn="section-6.2.3-9">In summary:
          </t>
          <ul spacing="compact">
            <li>Steps 1...4 spacing="normal" bare="false" empty="false" indent="3" pn="section-6.2.3-10">
            <li pn="section-6.2.3-10.1">
              <xref target="step1" format="none" sectionFormat="of" derivedContent="">Steps 1 through 4</xref> constitute standard certificate validity verification and private key authentication as defined by <xref target="RFC5280" format="default"/> format="default" sectionFormat="of" derivedContent="RFC5280"/> and security association protocols (such as Internet Key Exchange Protocol version 2 <xref target="RFC7296" format="default">IKEv2</xref> format="default" sectionFormat="of" derivedContent="RFC7296">IKEv2</xref>) when leveraging certificates. </li>
            <li>Steps 1...4
            <li pn="section-6.2.3-10.2">Except for its public key, <xref target="step1" format="none" sectionFormat="of" derivedContent="">Steps 1 through 4</xref> do not include the verification of any pre-existing preexisting
	    form of non-public-key-only based identity elements of a certificate certificate's identity
      elements, such as a web servers server's domain name prefix prefix, which is
      often encoded in the certificate common name. Step 5 <xref target="step5" format="none" sectionFormat="of" derivedContent="">Step 5</xref> is an equivalent step for the AcpNodeName.</li>
            <li>Step 4
            <li pn="section-6.2.3-10.3">
              <xref target="step4" format="none" sectionFormat="of" derivedContent="">Step 4</xref> constitutes standard CRL/OCSP CRL and OCSP checks refined for the case of missing connectivity and limited functionality limited-functionality security association protocols.</li>
            <li>Steps 1...4
            <li pn="section-6.2.3-10.4">
              <xref target="step1" format="none" sectionFormat="of" derivedContent="">Steps 1 through 4</xref> authorize to build the building of any secure connection between members of the same ACP domain except for ACP secure channels.</li>
            <li>Step 5
            <li pn="section-6.2.3-10.5">
              <xref target="step5" format="none" sectionFormat="of" derivedContent="">Step 5</xref> is the additional verification of the presence of an ACP address as necessary for ACP secure channels.</li>
            <li>Steps 1...5
            <li pn="section-6.2.3-10.6">
              <xref target="step1" format="none" sectionFormat="of" derivedContent="">Steps 1 through 5</xref> therefore authorize to build the building of an ACP secure channel.</li>
          </ul>
          <t>For
          <t indent="0" pn="section-6.2.3-11">For brevity, the remainder of this document refers to this process only as authentication instead of as authentication and authorization.</t>

          <t>[RFC-Editor: Please remove the following paragraph].</t>
          <t>Note that the ACP domain membership check does not verify the network layer address of the security association. See <xref target="ACPDRAFT"/>, Appendix B.2 for explanations.</t>
          <section anchor="cert-time" numbered="true" toc="default">
            <name>Realtime clock toc="include" removeInRFC="false" pn="section-6.2.3.1">
            <name slugifiedName="name-realtime-clock-and-time-val">Realtime Clock and Time Validation</name>
            <t>An
            <t indent="0" pn="section-6.2.3.1-1">An ACP node with a realtime clock in which it has confidence, MUST confidence <bcp14>MUST</bcp14>
            check the time stamps timestamps when performing an ACP domain membership check check, such
            as checking the certificate validity period in step 1. <xref target="step1" format="none" sectionFormat="of" derivedContent="">Step 1</xref> and the respective
            times in step 4 <xref target="step4" format="none" sectionFormat="of" derivedContent="">Step 4</xref> for revocation information (e.g., signingTimes in CMS Cryptographic Message Syntax (CMS) signatures).</t>
            <t>An
            <t indent="0" pn="section-6.2.3.1-2">An ACP node without such a realtime clock MAY <bcp14>MAY</bcp14> ignore those time
            stamp timestamp
            validation steps if it does not know the current time.
            Such an ACP node SHOULD <bcp14>SHOULD</bcp14> obtain the current time in a
            secured fashion, such as via a Network Time Protocol NTP signaled through the ACP.
            It then ignores time stamp timestamp validation only until the current time is known.
            In the absence of implementing a secured mechanism, such an ACP node MAY <bcp14>MAY</bcp14>
            use a current time learned in an insecure fashion in the ACP domain membership
            check.</t>
            <t>Current
            <t indent="0" pn="section-6.2.3.1-3">Current time MAY for example <bcp14>MAY</bcp14> be learned in an unsecured fashion, for example, via NTP (<xref ("<xref target="RFC5905" format="default"/>) format="title" sectionFormat="of" derivedContent="Network Time Protocol Version 4: Protocol and Algorithms Specification"/>" <xref target="RFC5905" format="default" sectionFormat="of" derivedContent="RFC5905"/>)
            over the same link-local IPv6 addresses used for the ACP from neighboring ACP nodes.
            ACP nodes that do provide unsecured NTP insecure over their link-local addresses SHOULD <bcp14>SHOULD</bcp14>
            primarily run NTP across the ACP and provide NTP time across the ACP only
            when they have a trusted time source. Details for such NTP procedures are beyond the
            scope of this specification.</t>
            <t>Beside
            <t indent="0" pn="section-6.2.3.1-4">Besides the ACP domain membership check, the ACP itself has no
            dependency against knowledge of on knowing the current time, but protocols
            and services using the ACP ACP, for example, event logging, will likely have the need to know
            the current time. For example, event logging.</t> time.</t>
          </section>
        </section>
        <section anchor="trust-anchors" numbered="true" toc="default">
          <name>Trust toc="include" removeInRFC="false" pn="section-6.2.4">
          <name slugifiedName="name-trust-anchors-ta">Trust Anchors (TA)</name>
          <t>ACP
          <t indent="0" pn="section-6.2.4-1">ACP nodes need TA information according to <xref target="RFC5280" format="default"/>,
section 6.1.1 sectionFormat="comma" section="6.1.1" format="default" derivedLink="https://rfc-editor.org/rfc/rfc5280#section-6.1.1" derivedContent="RFC5280"/> (d), typically in the form of one or more certificate certificates of the TA to perform certificate
path validation as required by <xref target="certcheck" format="default"/>, rule 2. target="step2" format="none" sectionFormat="of" derivedContent="">Section 6.2.3, Rule 2</xref>.
TA information MUST <bcp14>MUST</bcp14> be provisioned to an ACP node (together with its ACP
domain certificate) by an ACP Registrar registrar during initial enrollment of a candidate
ACP node. ACP nodes MUST <bcp14>MUST</bcp14> also support the renewal of TA information via
EST as described below in <xref target="domcert-maint" format="default"/>.</t>

          <t>The format="default" sectionFormat="of" derivedContent="Section 6.2.5"/>.</t>
          <t indent="0" pn="section-6.2.4-2">The required information about a TA can consist of not only a single, but
multiple
one or more
certificates as required for dealing with CA certificate renewals
as explained in Section 4.4 <xref target="RFC4210" section="4.4" sectionFormat="bare" format="default" derivedLink="https://rfc-editor.org/rfc/rfc4210#section-4.4" derivedContent="RFC4210"/> of CMP (<xref <xref target="RFC4210" format="default"/>).</t>
          <t>A format="default" sectionFormat="of" derivedContent="RFC4210">"Internet X.509 Public Key Infrastructure Certificate Management Protocol (CMP)"</xref>).</t>
          <t indent="0" pn="section-6.2.4-3">A certificate path is a chain of certificates starting at
the ACP certificate (leaf/end-entity) (the leaf and/or end entity), followed by zero or more
intermediate CA certificates certificates, and ending with the TA information,
which are is typically one or two the self-signed certificates of the TA. The
CA that signs the ACP certificate is called the assigning CA.
If there are no intermediate CA, CAs, then the assigning CA is the TA.
Certificate path validation authenticates that the ACP certificate is permitted
by a TA associated with the ACP, ACP permits the ACP certificate, either directly or indirectly via one or more intermediate
CA.</t>
          <t>Note
          <t indent="0" pn="section-6.2.4-4">Note that different ACP nodes may have different intermediate CA CAs
in their certificate path and even different TA. The set of TA TAs for
an ACP domain must be consistent across all ACP members so that any ACP node
can authenticate any other ACP node.  The protocols through which the
ACP domain membership check rules 1-3 <xref target="step1" format="none" sectionFormat="of" derivedContent="">Rules 1 through 3</xref> are performed need to support
the exchange not only of the ACP nodes certificates, certificates but also the exchange of
the intermedia intermediate TA.</t>
          <t>ACP nodes MUST support for
          <t indent="0" pn="section-6.2.4-5">For the ACP domain membership check the check, ACP nodes <bcp14>MUST</bcp14> support certificate path
validation with 0 zero or 1 one intermediate CA. They SHOULD <bcp14>SHOULD</bcp14> support 2 two intermediate CA CAs
and two TA TAs (to permit migration to from one TA to another TA).</t>
          <t>Certificates
          <t indent="0" pn="section-6.2.4-6">Certificates for an ACP MUST <bcp14>MUST</bcp14> only be given to nodes that are allowed
to be members of that ACP. When the signing CA relies on an ACP
Registrar, registrar,
the CA  MUST <bcp14>MUST</bcp14> only sign certificates with acp-node-name
through trusted ACP Registrars. registrars. In this setup, any existing CA, unaware of the formatting
of acp-node-name, can be used.</t>
          <t>These
          <t indent="0" pn="section-6.2.4-7">These requirements can be achieved by using a TA private to the owner of
the ACP domain or potentially through appropriate contractual agreements between
the involved parties (Registrar (registrar and CA).  Using a public CA is out of scope of this
document. [RFC-Editor: please remove the following sentence]. See <xref target="ACPDRAFT"/>, Appendix B.3 for further considerations.</t>

          <t>A  </t>
          <t indent="0" pn="section-6.2.4-8">A single owner can operate multiple multiple, independent ACP domains from the same
set of TA. TAs. Registrars must then know into which ACP a node needs to be enrolled into.</t> enrolled.</t>
        </section>
        <section anchor="domcert-maint" numbered="true" toc="default">
          <name>Certificate toc="include" removeInRFC="false" pn="section-6.2.5">
          <name slugifiedName="name-certificate-and-trust-ancho">Certificate and Trust Anchor Maintenance</name>

          <t>ACP
          <t indent="0" pn="section-6.2.5-1">ACP nodes MUST <bcp14>MUST</bcp14> support renewal of their Certificate certificate and TA information via EST
and MAY <bcp14>MAY</bcp14> support other mechanisms.  See <xref target="tls" format="default"/> format="default" sectionFormat="of" derivedContent="Section 6.1"/> for TLS requirements.
An ACP network MUST <bcp14>MUST</bcp14> have at least one ACP node supporting EST server functionality across the ACP so that EST
renewal is useable.</t>

<t>ACP usable.</t>
          <t indent="0" pn="section-6.2.5-2">ACP nodes SHOULD be able to <bcp14>SHOULD</bcp14> remember the IPv6 locator parameters of
the O_IPv6_LOCATOR in GRASP O_IPv6_LOCATOR parameters of
   the EST server from with which they last renewed their ACP certificate.
They SHOULD <bcp14>SHOULD</bcp14> provide the ability
for these EST server parameters to also be set by the ACP Registrar registrar
(see <xref target="acp-registrars" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 6.11.7"/>) that initially enrolled the ACP
device with its ACP certificate. When BRSKI
is used (see <xref target="I-D.ietf-anima-bootstrapping-keyinfra" format="default"/>)
is used, target="RFC8995" format="default" sectionFormat="of" derivedContent="RFC8995"/>), the IPv6 locator of the BRSKI registrar from the BRSKI TLS
connection SHOULD <bcp14>SHOULD</bcp14> be remembered and used for the next renewal via
EST if that registrar also announces itself as an EST server
via GRASP (see next section) on its ACP address.</t>
          <t>The address (see <xref target="domcert-grasp" format="default" sectionFormat="of" derivedContent="Section 6.2.5.1"/>).</t>
          <t indent="0" pn="section-6.2.5-3">The EST server MUST <bcp14>MUST</bcp14> present a certificate that is passing passes the ACP domain
membership check in its TLS connection setup (<xref target="certcheck" format="default"/>, target="step1" format="none" sectionFormat="of" derivedContent="">Section 6.2.3, rules 1...4, 1 through 4</xref>, not rule 5 <xref target="step5" format="none" sectionFormat="of" derivedContent="">rule 5</xref> as this is not for an ACP secure channel setup).
The EST server certificate MUST <bcp14>MUST</bcp14> also contain the id-kp-cmcRA <xref target="RFC6402" format="default"/>
extended key usage attribute <xref target="RFC6402" format="default" sectionFormat="of" derivedContent="RFC6402"/>, and the EST client MUST <bcp14>MUST</bcp14> check its presence.</t>
          <t>The
          <t indent="0" pn="section-6.2.5-4">The additional check against the id-kp-cmcRA extended key usage extension field
ensures that clients do not fall prey to an illicit EST server.  While such
illicit EST servers should not be able to support certificate signing requests (as they
are not able to elicit a signing response from a valid CA), such an illicit EST server would
be able to provide faked CA certificates to EST clients that need to renew their
CA certificates when they expire.</t>
          <t>Note
          <t indent="0" pn="section-6.2.5-5">Note that EST servers supporting multiple ACP domains will need to have
a separate certificate for each of these ACP domains a separate certificate and respond on a different transport
address (IPv6 address and/or TCP port), but this port). This is easily automated on the
EST server as long as if the CA does not restrict allows registrars to request certificates
with the id-kp-cmcRA extended usage extension for themselves.</t>
          <section anchor="domcert-grasp" numbered="true" toc="default">
            <name>GRASP objective toc="include" removeInRFC="false" pn="section-6.2.5.1">
            <name slugifiedName="name-grasp-objective-for-est-ser">GRASP Objective for EST server</name>
            <t>ACP Server</name>
            <t indent="0" pn="section-6.2.5.1-1">ACP nodes that are EST servers MUST <bcp14>MUST</bcp14> announce their service via GRASP in the ACP
through M_FLOOD via GRASP
Flood Synchronization (M_FLOOD) messages. See <xref target="I-D.ietf-anima-grasp" format="default"/>,
section 2.8.11 target="RFC8990" sectionFormat="comma" section="2.8.11" format="default" derivedLink="https://rfc-editor.org/rfc/rfc8990#section-2.8.11" derivedContent="RFC8990"/> for the definition of this message type:</t>
            <figure anchor="est-example">
              <name>GRASP SRV.est example</name>
              <artwork name="" type="" type
and <xref target="est-example" format="default" sectionFormat="of" derivedContent="Figure 4"/> for an example.</t>
            <figure anchor="est-example" align="left" alt=""><![CDATA[
     Example: suppress-title="false" pn="figure-4">
              <name slugifiedName="name-grasp-srvest-objective-exam">GRASP "SRV.est" Objective Example</name>
              <sourcecode name="" type="" markers="false" pn="section-6.2.5.1-2.1">
   [M_FLOOD, 12340815, h'fd89b714f3db0000200000064000001', 210000,
       [["SRV.est", 4, 255 ],
       [O_IPv6_LOCATOR,
            h'fd89b714f3db0000200000064000001', IPPROTO_TCP, 443]]
   ]
 ]]></artwork>
</sourcecode>
            </figure>
            <t>
            <t indent="0" pn="section-6.2.5.1-3"> The formal definition of the objective in Concise data definition language (CDDL) CDDL
   (see "<xref target="RFC8610" format="title" sectionFormat="of" derivedContent="Concise Data Definition Language (CDDL): A Notational Convention to Express Concise Binary Object Representation (CBOR) and JSON Data Structures"/>" <xref target="RFC8610" format="default"/>) format="default" sectionFormat="of" derivedContent="RFC8610"/>) is as follows: </t>
            <figure anchor="est-def">
              <name>GRASP SRV.est definition</name>
              <artwork name="" type="" anchor="est-def-fig" align="left" alt=""><![CDATA[ suppress-title="false" pn="figure-5">
              <name slugifiedName="name-grasp-srvest-definition">GRASP "SRV.est" Definition</name>
              <sourcecode name="" type="cddl" markers="false" pn="section-6.2.5.1-4.1">
flood-message = [M_FLOOD, session-id, initiator, ttl,
                 +[objective, (locator-option / [])]]
                             ; see See example above and explanation
                             ; below for initiator and ttl ttl.

objective = ["SRV.est", objective-flags, loop-count,
                                       objective-value]

objective-flags = sync-only  ; as As in GRASP spec [RFC8990].
sync-only       = 4          ; M_FLOOD only requires synchronization synchronization.
loop-count      = 255        ; recommended Recommended as there is no mechanism
                             ; to discover network diameter.
objective-value = any        ; reserved Reserved for future extensions

 ]]></artwork> extensions.
</sourcecode>
            </figure>
            <t>The
            <t indent="0" pn="section-6.2.5.1-5">The objective name "SRV.est" indicates that the objective is an
<xref target="RFC7030" format="default"/> compliant EST server compliant with
<xref target="RFC7030" format="default" sectionFormat="of" derivedContent="RFC7030"/> because "est" is an
<xref target="RFC6335" format="default"/> a
registered service name ("<xref target="RFC6335" format="title" sectionFormat="of" derivedContent="Internet Assigned Numbers Authority (IANA) Procedures for the Management of the Service Name and Transport Protocol Port Number Registry"/>" <xref target="RFC6335" format="default" sectionFormat="of" derivedContent="RFC6335"/>) for <xref target="RFC7030" format="default"/>.
Objective-value MUST format="default" sectionFormat="of" derivedContent="RFC7030"/>.
The 'objective-value' field <bcp14>MUST</bcp14> be ignored if present. Backward compatible Backward-compatible extensions to
<xref target="RFC7030" format="default"/> MAY format="default" sectionFormat="of" derivedContent="RFC7030"/> <bcp14>MAY</bcp14> be indicated through objective-value.
Non <xref target="RFC7030" format="default"/> compatible certificate 'objective-value'.
Certificate renewal options MUST that are incompatible with <xref target="RFC7030" format="default" sectionFormat="of" derivedContent="RFC7030"/> <bcp14>MUST</bcp14> use a different objective-name.
Non-recognized objective-values 'objective-name'.
Unrecognized 'objective-value' fields (or parts thereof if it is a structure partially understood) MUST understood structure) <bcp14>MUST</bcp14> be ignored.</t>
            <t>The
            <t indent="0" pn="section-6.2.5.1-6">The M_FLOOD message MUST <bcp14>MUST</bcp14> be sent periodically.  The default SHOULD <bcp14>SHOULD</bcp14> be 60 seconds;
the value SHOULD <bcp14>SHOULD</bcp14> be operator configurable but SHOULD <bcp14>SHOULD</bcp14> be
not smaller than 60 seconds.  The frequency of sending MUST <bcp14>MUST</bcp14> be such
that the aggregate amount of periodic M_FLOODs from all flooding sources
cause only negligible traffic across the ACP.  The time-to-live (ttl) parameter SHOULD <bcp14>SHOULD</bcp14> be 3.5 times the period so that up
to three consecutive messages can be dropped before considering an announcement is considered expired.
In the example above, the ttl is 210000 msec, that is, 3.5 times 60 seconds. When a service announcer
using these parameters unexpectedly dies immediately after sending the M_FLOOD,
receivers would consider it expired 210 seconds later. When a receiver tries to
connect to this dead service before this timeout, it will experience a failing connection and
use that as an indication that the service instance is dead and select another instance of the
same service instead (from another GRASP announcement).</t>
<t>The
            <t indent="0" pn="section-6.2.5.1-7">The "SRV.est" objective(s) SHOULD <bcp14>SHOULD</bcp14> only be announced when the ACP node knows that it can successfully
communicate with a CA to perform the EST renewal/rekeying renewal and/or rekeying operations for the ACP domain. See also
<xref target="security"/>.</t> target="security" format="default" sectionFormat="of" derivedContent="Section 11"/>.</t>
          </section>
          <section anchor="domcert-renewal" numbered="true" toc="default">
            <name>Renewal</name>
            <t>When toc="include" removeInRFC="false" pn="section-6.2.5.2">
            <name slugifiedName="name-renewal">Renewal</name>
            <t indent="0" pn="section-6.2.5.2-1">When performing renewal, the node SHOULD <bcp14>SHOULD</bcp14> attempt to connect to the remembered EST server.
If that fails, it SHOULD <bcp14>SHOULD</bcp14> attempt to connect to an EST server learned via GRASP.  The server
with which certificate renewal succeeds SHOULD <bcp14>SHOULD</bcp14> be remembered for the next renewal.</t>
            <t>Remembering
            <t indent="0" pn="section-6.2.5.2-2">Remembering the last renewal server and preferring it provides stickiness
which
that can help diagnostics.  It also provides some protection against off-path off-path,
compromised ACP members announcing bogus information into GRASP.</t>
            <t>Renewal
            <t indent="0" pn="section-6.2.5.2-3">Renewal of certificates SHOULD <bcp14>SHOULD</bcp14> start after less than 50% of the domain certificate
lifetime so that network operations has have ample time to investigate and
resolve any problems that causes cause a node to not renew its domain certificate
in time - time, and to allow prolonged periods of running parts of a network
disconnected from any CA.</t>
          </section>
          <!-- DO NOT FORCE THE TTL=255 OPTION RIGHT NOW.
     IT MIGHT MAKE MORE SENSE TO DO FOLLOWUP WORK IN WHICH
     WE DO PROVIDE A MORE COMPLETE SET OF SELECTION OPTIONS
     COMPATIBLE WITH DNS-SD - 10/2017, Toerless Eckert

<t>The locator-option indicates the ACP transport address for the EST server.
The loop-count MUST be set to 255.  When an ACP node receives the M_FLOOD,
it will have been reduced by the number of hops from the EST server.</t>

<t>When it is time for domain certificate renewal, the ACP node MUST
attempt to connect to the EST server(s) learned via GRASP starting with
the one that has the highest remaining loop-count (closest one).  If
certificate renewal does not succeed, the node MUST attempt to use
the EST server(s) learned during initial provisioning/enrollment of
the certificate.  After successful renewal of the domain certificate,
the ACP address from the certificate of the EST server as learned
during the handshake of the TLS connection to the EST server MAY be remembered
could be preferred for future renewal operations.  As long
as that EST server is reachable, this provides stickiness in the selection of
the EST server and can simplify troubleshooting.</t>

<t>This logic of selecting an EST server for renewal is chosen to allow
for distributed EST servers to be used effectively but to also allow
fallback to the most reliably learned EST server - those that performed
already successful enrollment in before.  A compromised (non EST-server)
ACP node for example can filter or fake GRASP announcements, but it can
not successfully renew a certificate and can only prohibit traffic to
a valid EST server when it is on the path between the ACP node and the
EST server.</t>

-->
          <section anchor="domcert-crl" numbered="true" toc="default">
            <name>Certificate toc="include" removeInRFC="false" pn="section-6.2.5.3">
            <name slugifiedName="name-certificate-revocation-list">Certificate Revocation Lists (CRLs)</name>
            <t>The
            <t indent="0" pn="section-6.2.5.3-1">The ACP node SHOULD <bcp14>SHOULD</bcp14> support revocation through CRL(s) via HTTP from one
or more CRL Distribution Points (CRLDP).  The CRLDP(s) MUST <bcp14>MUST</bcp14> be indicated
in the Domain Certificate domain certificate when used.  If the CRLDP URL uses an IPv6 address
(ULA address when using the addressing rules specified in this document),
the ACP node will connect to the CRLDP via the ACP.  If the CRLDP uses a
domain name, the ACP node will connect to the CRLDP via the Data-Plane.</t>
            <t>It data plane.</t>
            <t indent="0" pn="section-6.2.5.3-2">It is common to use domain names for CRLDP(s), but there is no requirement
for the ACP to support DNS. Any DNS lookup in the Data-Plane data plane is
not only a possible security issue, but it would also not indicate whether
the resolved address is meant to be reachable across the ACP. Therefore,
the use of an IPv6 address versus the use of a DNS name doubles as an
indicator whether or not to reach the CRLDP via the ACP.</t>
<t>A
            <t indent="0" pn="section-6.2.5.3-3">A CRLDP can be reachable across the ACP either by running it on a
node with ACP or by connecting its node via an ACP connect interface (see <xref target="ACPconnect" format="default"/>).</t>

<t>When format="default" sectionFormat="of" derivedContent="Section 8.1"/>).</t>
            <t indent="0" pn="section-6.2.5.3-4">When using a private PKI for ACP certificates, the CRL may be need-to-know, for example example,
to prohibit insight into the operational practices of the domain by tracking
the growth of the CRL.  In this case, HTTPS may be chosen to provide
confidentiality, especially when making the CRL available via the Data-Plane. data plane.
Authentication and authorization SHOULD <bcp14>SHOULD</bcp14> use ACP certificates and the ACP domain membership check. check (<xref target="certcheck" format="default" sectionFormat="of" derivedContent="Section 6.2.3"/>).
The CRLDP MAY <bcp14>MAY</bcp14> omit the CRL verification during authentication of the peer to permit
retrieval of the
CRL retrieval by an ACP node with a revoked ACP certificate. This certificate, which can allow for that the
(ex) ACP node to quickly discover its ACP certificate revocation. This may violate
the desired need-to-know requirement requirement, though. ACP nodes MAY <bcp14>MAY</bcp14> support CRLDP operations
via HTTPS.</t>

<!--
<t>The CRLDP SHOULD use an ACP certificate for its HTTPs connections.
The connecting ACP node SHOULD verify that the CRLDP certificate used
during the HTTPs connection has the same ACP address as indicated in the
CRLDP URL of the node's ACP certificate if the CRLDP URL uses an IPv6 address.</t>
-->
          </section>
          <section anchor="domcert-lifetime" numbered="true" toc="default">
            <name>Lifetimes</name>
            <t>Certificate toc="include" removeInRFC="false" pn="section-6.2.5.4">
            <name slugifiedName="name-lifetimes">Lifetimes</name>
            <t indent="0" pn="section-6.2.5.4-1">The certificate lifetime may be set to shorter lifetimes than customary
(1
(one year) because certificate renewal is fully automated via ACP and EST.
The primary limiting factor for shorter certificate lifetimes
is the load on the EST server(s) and CA.  It is therefore recommended that
ACP certificates are managed via a CA chain where the assigning
CA has enough performance to manage short lived short-lived certificates. See also
<xref target="sub-ca" format="default"/> format="default" sectionFormat="of" derivedContent="Section 9.2.4"/> for a discussion about an example setup achieving
this. See also "<xref target="RFC8739" format="title" sectionFormat="of" derivedContent="Support for Short-Term, Automatically Renewed (STAR) Certificates in the Automated Certificate Management Environment (ACME)"/>" <xref target="I-D.ietf-acme-star" format="default"/>.</t>
            <t>When target="RFC8739" format="default" sectionFormat="of" derivedContent="RFC8739"/>.</t>
            <t indent="0" pn="section-6.2.5.4-2">When certificate lifetimes are sufficiently short, such as few hours,
certificate revocation may not be necessary, allowing to simplify the simplification of the overall
certificate maintenance infrastructure.</t>
            <t>See
            <t indent="0" pn="section-6.2.5.4-3">See <xref target="bootstrap" format="default"/> format="default" sectionFormat="of" derivedContent="Appendix A.2"/> for further optimizations of certificate
maintenance when BRSKI can be used ("Bootstrapping Remote Secure Key
Infrastructures", see <xref target="I-D.ietf-anima-bootstrapping-keyinfra" format="default"/>).</t> target="RFC8995" format="default" sectionFormat="of" derivedContent="RFC8995"/>.</t>
          </section>
          <section anchor="domcert-re-enroll" numbered="true" toc="default">
            <name>Re-enrollment</name>
            <t>An toc="include" removeInRFC="false" pn="section-6.2.5.5">
            <name slugifiedName="name-reenrollment">Reenrollment</name>
            <t indent="0" pn="section-6.2.5.5-1">An ACP node may determine that its ACP certificate
has expired, for example example, because the ACP node was powered down or
disconnected longer than its certificate lifetime. In this case, the ACP
node SHOULD <bcp14>SHOULD</bcp14> convert to a role of a re-enrolling reenrolling candidate ACP node.</t>
            <t>In
            <t indent="0" pn="section-6.2.5.5-2">In this role, the node does maintain maintains the TA and certificate
chain associated with its ACP certificate exclusively for the purpose
of re-enrollment, reenrollment, and it attempts (or waits) to get re-enrolled reenrolled with a new ACP
certificate.  The details depend on the mechanisms/protocols mechanisms and protocols used
by the ACP Registrars.</t>
            <t>Please registrars.</t>
            <t indent="0" pn="section-6.2.5.5-3">Please refer to <xref target="acp-registrars" format="default"/> format="default" sectionFormat="of" derivedContent="Section 6.11.7"/> and <xref target="I-D.ietf-anima-bootstrapping-keyinfra" format="default"/> target="RFC8995" format="default" sectionFormat="of" derivedContent="RFC8995"/>
for explanations about ACP Registrars registrars and vouchers as used in the following text.
When ACP is intended to be used without BRSKI, the details about BRSKI and
vouchers in the following text can be skipped.</t>
            <t>When
            <t indent="0" pn="section-6.2.5.5-4">When BRSKI is used (i.e.: (i.e., on ACP nodes that are ANI nodes), the re-enrolling reenrolling
candidate ACP node would attempt attempts to enroll like a candidate ACP node (BRSKI pledge),
but instead of using the ACP nodes node's IDevID certificate, it SHOULD <bcp14>SHOULD</bcp14> first attempt to use its ACP domain
certificate in the BRSKI TLS authentication.  The BRSKI registrar MAY <bcp14>MAY</bcp14> honor
this certificate beyond its expiration date purely for the purpose of
re-enrollment.
reenrollment. Using the ACP node's domain certificate allows the BRSKI
registrar to learn that node's acp-node-name, acp-node-name
so that the BRSKI registrar can re-assign reassign the same ACP address information
to the ACP node in the new ACP certificate.</t>

            <t>If
            <t indent="0" pn="section-6.2.5.5-5">If the BRSKI registrar denies the use of the old ACP certificate,
the re-enrolling reenrolling candidate ACP node MUST re-attempt re-enrollment <bcp14>MUST</bcp14> reattempt reenrollment using
its IDevID certificate as defined in BRSKI during the TLS connection setup.</t>

            <t>Both when
            <t indent="0" pn="section-6.2.5.5-6">When the BRSKI connection is attempted with either with the old ACP certificate
or the IDevID certificate, the re-enrolling reenrolling candidate ACP node SHOULD <bcp14>SHOULD</bcp14> authenticate
the BRSKI registrar during TLS connection setup based on its existing TA
certificate chain information associated with its old ACP certificate.
The re-enrolling reenrolling candidate ACP node SHOULD <bcp14>SHOULD</bcp14> only fall back to requesting a voucher from the BRSKI registrar
when this authentication fails during TLS connection setup.
As a countermeasure against attacks that attempt to force the ACP node to forget its prior (expired) certificate
and TA, the ACP node should alternate between attempting to re-enroll reenroll using
its old keying material and attempting to re-enroll reenroll with its IDevID and requesting
a voucher.</t>

            <t>When other
            <t indent="0" pn="section-6.2.5.5-7">When mechanisms other than BRSKI are used for ACP certificate
enrollment, the principles of the re-enrolling reenrolling candidate ACP node are the same.
The re-enrolling reenrolling candidate ACP node attempts to authenticate any ACP Registrar registrar peers
during re-enrollment protocol/mechanisms
using reenrollment protocols and/or mechanisms via its existing certificate chain/TA chain and/or TA information
and provides its existing ACP certificate and other identification
(such as the IDevID certificate) as necessary to the registrar.</t>

            <t>Maintaining
            <t indent="0" pn="section-6.2.5.5-8">Maintaining existing TA information is especially important
when using enrollment mechanisms are used that unlike BRSKI do not leverage
a mechanism (such as the voucher in BRSKI) to authenticate the ACP registrar (such as the voucher in BRSKI),
and where therefore when the injection of certificate failures could otherwise make the ACP node easily
attackable remotely by returning vulnerable to remote
attacks by returning the ACP node to a "duckling" state in which
it accepts to be enrolled enrollment by any network it connects to. The (expired) ACP
certificate and ACP TA SHOULD <bcp14>SHOULD</bcp14> therefore be maintained and attempted to be used as one possible credential for re-enrollment reenrollment
until new keying material is acquired.</t>

            <t>When
            <t indent="0" pn="section-6.2.5.5-9">When using BRSKI or other protocol/mechanisms supporting protocols and/or mechanisms that support vouchers,
maintaining existing TA information allows for re-enrollment lighter-weight reenrollment
of expired ACP certificates to be more lightweight, certificates, especially in
environments where repeated acquisition of vouchers during the lifetime
of ACP nodes may be operationally expensive or otherwise undesirable.</t>
          </section>
          <section anchor="domcert-failing" numbered="true" toc="default">
            <name>Failing toc="include" removeInRFC="false" pn="section-6.2.5.6">
            <name slugifiedName="name-failing-certificates">Failing Certificates</name>
            <t>An
            <t indent="0" pn="section-6.2.5.6-1">An ACP certificate is called failing in this document,
if/when document
if or when the ACP node to which the certificate was issued can determine that it was revoked (or explicitly
not renewed), or in the absence of such explicit local diagnostics,
when the ACP node fails to connect to other ACP nodes in the same ACP
domain using its ACP certificate. For connection failures to To
determine that the ACP certificate as is the culprit, culprit of a connection failure, the peer
should pass the domain membership check (<xref target="certcheck" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 6.2.3"/>),
and connection error diagnostics should exclude other reasons for the connection failure can be excluded because of
the connection error diagnostics.</t>
            <t>This failure.</t>
            <t indent="0" pn="section-6.2.5.6-2">This type of failure can happen during setup/refresh the setup or refreshment of a secure ACP channel
connections
connection or during any other use of the ACP certificate, such as for the
TLS connection to an EST server for the renewal of the ACP domain
certificate.</t>
            <t>Example reasons for
            <t indent="0" pn="section-6.2.5.6-3">The following are examples of failing certificates that the ACP node can only
discover through connection failure are that failure: the domain certificate or
any of its signing certificates could have been revoked or may have expired,
but the ACP node cannot self-diagnose diagnose this condition directly. directly by itself. Revocation
information or clock synchronization may only be available across the ACP,
but the ACP node cannot build ACP secure channels because the ACP peers reject
the ACP node's domain certificate.</t>
            <t>ACP nodes SHOULD
            <t indent="0" pn="section-6.2.5.6-4">An ACP node <bcp14>SHOULD</bcp14> support the option to determines determine whether its ACP
certificate is failing, and when it does, put itself into the role of a
re-enrolling
reenrolling candidate ACP node as explained above (<xref in <xref target="domcert-re-enroll" format="default"/>).</t> format="default" sectionFormat="of" derivedContent="Section 6.2.5.5"/>.</t>
          </section>
        </section>
        <!-- domcert-maint -->
      </section>
      <!-- domcert -->
      <section anchor="adj-table" numbered="true" toc="default">
        <name>ACP toc="include" removeInRFC="false" pn="section-6.3">
        <name slugifiedName="name-acp-adjacency-table">ACP Adjacency Table</name>
        <t>To
        <t indent="0" pn="section-6.3-1">To know to which nodes to establish an ACP channel, every ACP node maintains an adjacency table.  The adjacency table contains information about adjacent ACP nodes, at a minimum: Node-ID (identifier (the identifier of the node inside the ACP, see <xref target="zone-scheme" format="default"/> format="default" sectionFormat="of" derivedContent="Section 6.11.3"/> and <xref target="Vlong" format="default"/>), format="default" sectionFormat="of" derivedContent="Section 6.11.5"/>), the interface on which neighbor was discovered (by GRASP as explained below), the link-local IPv6 address of the neighbor on that interface, and the certificate (including acp-node-name).  An ACP node MUST <bcp14>MUST</bcp14> maintain this adjacency table.  This table is used to determine to which neighbor an ACP connection is established.</t>
        <t>Where
        <t indent="0" pn="section-6.3-2">When the next ACP node is not directly adjacent (i.e., not on a link
connected to this node), the information in the adjacency table can be supplemented by configuration.  For example, the Node-ID and IP address could be configured. See <xref target="remote-acp-neighbors" format="default"/>.</t>
        <t>The format="default" sectionFormat="of" derivedContent="Section 8.2"/>.</t>
        <t indent="0" pn="section-6.3-3">The adjacency table MAY <bcp14>MAY</bcp14> contain information about the validity and trust of the adjacent ACP node's certificate.  However, subsequent steps MUST <bcp14>MUST</bcp14> always start with the ACP domain membership check against the peer (see <xref target="certcheck" format="default"/>).</t>
        <t>The format="default" sectionFormat="of" derivedContent="Section 6.2.3"/>).</t>
        <t indent="0" pn="section-6.3-4">The adjacency table contains information about adjacent ACP nodes in general, independently independent of their domain and trust status.  The next step determines to which of those ACP nodes an ACP connection should be established.</t>
      </section>
      <section anchor="discovery-grasp" numbered="true" toc="default">
        <name>Neighbor toc="include" removeInRFC="false" pn="section-6.4">
        <name slugifiedName="name-neighbor-discovery-with-dul">Neighbor Discovery with DULL GRASP</name>
        <t>[RFC-Editor: GRASP draft is in RFC editor queue, waiting for dependencies, including ACP. Please ensure that references to I-D.ietf-anima-grasp that include section number references (throughout this document) will be updated in case any last-minute changes in GRASP would make those section references change.</t>
        <t>Discovery
        <t indent="0" pn="section-6.4-1">Discovery Unsolicited Link-Local (DULL) GRASP is a limited subset of GRASP intended to operate across an
insecure link-local scope.  See section 2.5.2 of <xref target="I-D.ietf-anima-grasp" format="default"/> target="RFC8990" sectionFormat="of" section="2.5.2" format="default" derivedLink="https://rfc-editor.org/rfc/rfc8990#section-2.5.2" derivedContent="RFC8990"/> for its
formal definition.  The ACP uses one instance of DULL GRASP for every L2 interface
of the ACP node to discover link level adjacent candidate ACP neighbors. neighbors that are link-level adjacent.  Unless modified
by policy as noted earlier (<xref target="overview" format="default"/> target="sec5bt2" format="none" sectionFormat="of" derivedContent="">Section 5, bullet point 2.), 2</xref>), native interfaces
(e.g., physical interfaces on physical nodes) SHOULD <bcp14>SHOULD</bcp14> be initialized automatically to a state in which
ACP discovery can be performed performed, and any native interfaces with ACP neighbors can
then be brought into the ACP even if the interface is otherwise not configured. unconfigured.
Reception of packets on such otherwise not configured unconfigured interfaces MUST <bcp14>MUST</bcp14> be limited so that
at first only IPv6 StateLess SLAAC ("<xref target="RFC4862" format="title" sectionFormat="of" derivedContent="IPv6 Stateless Address Auto Configuration (SLAAC - Autoconfiguration"/>" <xref target="RFC4862" format="default"/>) format="default" sectionFormat="of" derivedContent="RFC4862"/>)
 and DULL GRASP work work, and then only
the following ACP secure channel setup packets - work, but not any other unnecessary traffic
(e.g., no other link-local IPv6 transport stack responders responders, for example).</t>
        <t>Note
        <t indent="0" pn="section-6.4-2">Note that the use of the IPv6 link-local multicast address (ALL_GRASP_NEIGHBORS) implies
the need to use Multicast MLDv2 (see "<xref target="RFC3810" format="title" sectionFormat="of" derivedContent="Multicast Listener Discovery Version 2 (MLDv2, see (MLDv2) for IPv6"/>" <xref target="RFC3810" format="default"/>) format="default" sectionFormat="of" derivedContent="RFC3810"/>)
to announce the desire to receive packets for
that address.  Otherwise  Otherwise, DULL GRASP could fail to operate correctly in the presence of
MLD snooping (<xref target="RFC4541" format="default"/>)
MLD-snooping switches ("<xref target="RFC4541" format="title" sectionFormat="of" derivedContent="Considerations for Internet Group Management Protocol (IGMP) and Multicast Listener Discovery (MLD) Snooping Switches"/>" <xref target="RFC4541" format="default" sectionFormat="of" derivedContent="RFC4541"/>) that either do not support ACP or are not ACP supporting/enabled
 - enabled because those switches would stop forwarding DULL GRASP packets.
Switches that do not supporting support MLD snooping simply need to operate as pure L2 bridges for
IPv6 multicast packets for DULL GRASP to work.</t>
        <t>ACP
        <t indent="0" pn="section-6.4-3">ACP discovery SHOULD NOT <bcp14>SHOULD NOT</bcp14> be enabled by default on non-native interfaces.  In particular, ACP discovery MUST NOT <bcp14>MUST NOT</bcp14> run inside the ACP across ACP virtual interfaces.  See <xref target="enabling-acp" format="default"/> format="default" sectionFormat="of" derivedContent="Section 9.3"/> for further, further non-normative suggestions on how to enable/disable enable and disable ACP at the node and interface level.  See <xref target="conf-tunnel" format="default"/> format="default" sectionFormat="of" derivedContent="Section 8.2.2"/> for more details about tunnels (typical non-native interfaces).  See <xref target="acp-l2-switches" format="default"/> format="default" sectionFormat="of" derivedContent="Section 7"/> for how extending ACP should be extended on devices operating (also) as L2 bridges.</t>
        <t>Note: If
        <t indent="0" pn="section-6.4-4">Note: if an ACP node also implements BRSKI to enroll its ACP certificate
(see <xref target="bootstrap" format="default"/> format="default" sectionFormat="of" derivedContent="Appendix A.2"/> for a summary), then the above considerations also apply to
GRASP discovery for BRSKI.  Each DULL instance of GRASP
set up for ACP is then also used for the discovery of a bootstrap proxy via BRSKI when the node
does not have a domain certificate.
Discovery of ACP neighbors happens only when the node does have the certificate.  The node
therefore never needs to discover both a bootstrap proxy and an ACP neighbor at the same time.</t>
        <t>An
        <t indent="0" pn="section-6.4-5">An ACP node announces itself to potential ACP peers by use of the "AN_ACP" objective.
This is a synchronization objective intended to be flooded on a single link using the
GRASP Flood Synchronization (M_FLOOD) message.  In accordance with the design of the Flood Synchronization message,
a locator consisting of a specific link-local IP address, IP protocol number number, and port number
will be distributed with the flooded objective.  An example of the message is informally:</t>
        <figure anchor="an-acp-example">
          <name>GRASP AN_ACP example</name>
      <artwork anchor="an-acp-example" align="left" suppress-title="false" pn="figure-6">
          <name slugifiedName="name-grasp-an_acp-objective-exam">GRASP "AN_ACP" Objective Example</name>
          <sourcecode name="" type="" align="left" alt=""><![CDATA[ markers="false" pn="section-6.4-6.1">
   [M_FLOOD, 12340815, h'fe80000000000000c0011001feef0000', 210000,
     [["AN_ACP", 4, 1, "IKEv2" ],
      [O_IPv6_LOCATOR,
           h'fe80000000000000c0011001feef0000', IPPROTO_UDP, 15000]]
     [["AN_ACP", 4, 1, "DTLS" ],
      [O_IPv6_LOCATOR,
           h'fe80000000000000c0011001feef0000', IPPROTO_UDP, 17000]]
   ]
 ]]></artwork>
</sourcecode>
        </figure>
        <t>
        <t indent="0" pn="section-6.4-7"> The formal CDDL definition is: </t>
        <figure anchor="an-acp-def">
          <name>GRASP AN_ACP definition</name>
          <artwork name="" type="" anchor="an-acp-def" align="left" alt=""><![CDATA[ suppress-title="false" pn="figure-7">
          <name slugifiedName="name-grasp-an_acp-definition">GRASP "AN_ACP" Definition</name>
          <sourcecode name="" type="cddl" markers="false" pn="section-6.4-8.1">
  flood-message = [M_FLOOD, session-id, initiator, ttl,
                   +[objective, (locator-option / [])]]

  objective = ["AN_ACP", objective-flags, loop-count,
                                         objective-value]

  objective-flags = sync-only ; as in the GRASP specification [RFC8990]
  sync-only =  4    ; M_FLOOD only requires synchronization
  loop-count = 1    ; limit to link-local operation

  objective-value = method-name / [ method, *extension ]
  method = method-name / [ method-name, *method-param ]
  method-name = "IKEv2" / "DTLS" / id
  extension = any
  method-param = any
  id = text .regexp "[A-Za-z@_$]([-.]*[A-Za-z0-9@_$])*"
 ]]></artwork>
</sourcecode>
        </figure>
        <t>The objective-flags
        <t indent="0" pn="section-6.4-9">The 'objective-flags' field is set to indicate synchronization.</t>
        <t>The loop-count
        <t indent="0" pn="section-6.4-10">The 'loop-count' is fixed at 1 since this is a link-local operation.</t>
        <t>In
        <t indent="0" pn="section-6.4-11">In the above example example, the RECOMMENDED <bcp14>RECOMMENDED</bcp14> period of sending of the
    objective is 60 seconds. The indicated ttl 'ttl' of 210000 msec means
    that the objective would be cached by ACP nodes even when two
     out of three messages are dropped in transit.</t>
        <t>The session-id
        <t indent="0" pn="section-6.4-12">The 'session-id' is a random number used for loop prevention (distinguishing a message from a prior instance of the same message).  In DULL this field is irrelevant but has to be set according to the GRASP specification.</t>
        <t>The
        <t indent="0" pn="section-6.4-13">The originator MUST <bcp14>MUST</bcp14> be the IPv6 link local link-local address of the originating ACP node on the sending interface.</t>
        <t>The method-name
        <t indent="0" pn="section-6.4-14">The 'method-name' in the 'objective-value' parameter is a string indicating the protocol available at the specified or implied locator. It is a protocol supported by the node to negotiate a secure channel. IKEv2 "IKEv2" as shown above in <xref target="an-acp-example" format="default" sectionFormat="of" derivedContent="Figure 6"/> is the protocol used to negotiate an IPsec secure channel.</t>
        <t>Method-params
        <t indent="0" pn="section-6.4-15">The 'method-param' parameter allows method-specific parameters to carry method specific parameters. be carried. This specification does not define any method-param(s) 'method-param'(s) for "IKEv2" or "DTLS". Method-params Any method-params for these two methods that are not understood by an ACP node MUST <bcp14>MUST</bcp14> be ignored by it.</t>
        <t>extension(s)
        <t indent="0" pn="section-6.4-16">The 'extension' parameter allows to define method independent the definition of method-independent parameters. This specification does not define any extensions. Extensions not understood by an ACP node MUST <bcp14>MUST</bcp14> be ignored by it.</t>
        <t>The locator-option
        <t indent="0" pn="section-6.4-17">The 'locator-option' is optional and is only required when the secure channel protocol is not offered at a well-defined port number, or if there is no well-defined port number.</t>

        <t>IKEv2
        <t indent="0" pn="section-6.4-18">IKEv2 is the actual protocol used to negotiate an Internet Protocol security architecture (IPsec) IPsec connection.  GRASP therefore indicates "IKEv2" and not "IPsec". If "IPsec" was used, this too could mean the use of the obsolete obsolete, older version IKE (v1) (<xref ("<xref target="RFC2409" format="title" sectionFormat="of" derivedContent="The Internet Key Exchange (IKE)"/>" <xref target="RFC2409" format="default"/>). format="default" sectionFormat="of" derivedContent="RFC2409"/>).  IKEv2 has an IANA assigned IANA-assigned port number 500, but in the above example, <xref target="an-acp-example" format="default" sectionFormat="of" derivedContent="Figure 6"/>, the candidate ACP neighbor is offering ACP secure channel negotiation via IKEv2 on port 15000 (purely to show through the example that GRASP allows to indicate the indication of a port number number, and it does not have to be the IANA assigned one).</t>

        <t>There assigned).</t>
        <t indent="0" pn="section-6.4-19">There is no default UDP port for DTLS, it is always locally assigned by the node. For further details about the "DTLS" secure channel protocol, see <xref target="DTLS" format="default"/>.</t>

        <t>If format="default" sectionFormat="of" derivedContent="Section 6.8.4"/>.</t>
        <t indent="0" pn="section-6.4-20">If a locator is included, it MUST <bcp14>MUST</bcp14> be an O_IPv6_LOCATOR, and the IPv6 address MUST <bcp14>MUST</bcp14> be the same as the initiator address (these are DULL requirements to minimize third party third-party DoS attacks).</t>

        <t>The
        <t indent="0" pn="section-6.4-21">The secure channel methods defined in this document use the objective-values of "IKEv2" and "DTLS". "DTLS" for 'objective-value'.  There is no distinction between IKEv2 native and GRE-IKEv2 because this is purely negotiated via IKEv2.</t>
        <t>A
        <t indent="0" pn="section-6.4-22">A node that supports more than one secure channel protocol method needs to flood multiple versions
    of the "AN_ACP" objective so that each method can be accompanied by its own locator-option. 'locator-option'.  This can use a single GRASP M_FLOOD message as shown in <xref target="an-acp-example" format="default"/>.</t>
        <t>The format="default" sectionFormat="of" derivedContent="Figure 6"/>.</t>
        <t indent="0" pn="section-6.4-23">The primary use of DULL GRASP primarily serves is to discover the link-local IPv6 address of candidate ACP peers on subnets. The signaling of the supported secure channel option is primarily for diagnostic purposes, but it is also necessary for discovery when the protocol has no well-known transport address, such as in the case of DTLS. [RFC-Editor: Please remove the following sentence]. See <xref target="ACPDRAFT"/>, Appendix B.4.</t>

        <t>Note  </t>
        <t indent="0" pn="section-6.4-24">Note that a node serving both as an ACP node and BRSKI Join Proxy may choose to distribute the "AN_ACP" objective and the respective BRSKI in the same M_FLOOD message, since GRASP allows multiple objectives in one message.  This may be impractical though impractical, though, if ACP and BRSKI operations are implemented via separate software modules / and/or ASAs.</t>
        <t>The
        <t indent="0" pn="section-6.4-25">The result of the discovery is the IPv6 link-local address of the neighbor as well as its supported secure channel protocols (and the non-standard port they are running on).  It is stored in the ACP Adjacency Table adjacency table (see <xref target="adj-table" format="default"/>), format="default" sectionFormat="of" derivedContent="Section 6.3"/>), which then drives the further building of the ACP to that neighbor.</t>
        <t>Note
        <t indent="0" pn="section-6.4-26">Note that the described DULL GRASP objective described intentionally does not include the ACP node's ACP certificate certificate, even though this would be useful for diagnostics and to simplify the security exchange in ACP secure channel security association protocols (see <xref target="associations" format="default"/>). format="default" sectionFormat="of" derivedContent="Section 6.8"/>). The reason is that DULL GRASP messages are periodically multicasted multicast across IPv6 subnets subnets, and full certificates could easily lead to fragmented IPv6 DULL GRASP multicast packets due to the size of a certificate.  This would be highly undesirable.</t>
      </section>
      <!-- discovery-grasp -->
      <section anchor="selection" numbered="true" toc="default">
        <name>Candidate toc="include" removeInRFC="false" pn="section-6.5">
        <name slugifiedName="name-candidate-acp-neighbor-sele">Candidate ACP Neighbor Selection</name>
        <t>An
        <t indent="0" pn="section-6.5-1">An ACP node determines to which other ACP nodes in the adjacency table it should attempt to build an ACP connection.  This is based on the information in the ACP Adjacency adjacency table.</t>
        <t>The
        <t indent="0" pn="section-6.5-2">The ACP is established exclusively between nodes in the same domain.  This includes all routing subdomains. <xref target="domain-usage" format="default"/> format="default" sectionFormat="of" derivedContent="Appendix A.6"/> explains how ACP connections across multiple routing subdomains are special.</t>
        <t>The
        <t indent="0" pn="section-6.5-3">The result of the candidate ACP neighbor selection process is a list of adjacent or configured autonomic neighbors to which an ACP channel should be established.  The next step begins that channel establishment.</t>
      </section>
      <!-- selection -->
      <section anchor="channel-selection" numbered="true" toc="default">
        <name>Channel toc="include" removeInRFC="false" pn="section-6.6">
        <name slugifiedName="name-channel-selection">Channel Selection</name>
        <t>To
        <t indent="0" pn="section-6.6-1">To avoid attacks, the initial discovery of candidate ACP peers cannot include any non-protected unprotected negotiation.  To avoid re-inventing reinventing and validating security association mechanisms, the next step after discovering the address of a candidate neighbor can only be to try first is to establish a security association with that neighbor using a well-known security association method.</t>
        <t>From the use-cases it
        <t indent="0" pn="section-6.6-2">It seems clear from the use cases that not all type types of ACP nodes can or need to connect directly to each other or other, nor are they able to support or prefer all possible mechanisms.
  For example, code space limited IoT devices that are codespace limited may only support DTLS because that code exists already on them for end-to-end security, but low-end low-end, in-ceiling L2 switches may only want to support Media Access Control Security (MacSec, see 802.1AE (<xref <xref target="MACSEC" format="default"/>) format="default" sectionFormat="of" derivedContent="MACSEC"/>) because that is also supported in their chips.  Only a flexible gateway device may need to support both of these mechanisms and potentially more.  Note that MacSec is not required by any profiles of the ACP in this specification. Instead, MacSec is mentioned as a likely next an interesting potential secure channel protocol.  Note also that the security model allows and requires for any-to-any authentication and authorization between all ACP nodes because there is also end-to-end and not only hop-by-hop but also end-to-end authentication for secure channels.</t>
        <t>To
        <t indent="0" pn="section-6.6-3">To support extensible selection of the secure channel protocol selection without a single common mandatory to implement mandatory-to-implement (MTI) protocol, an ACP nodes MUST node <bcp14>MUST</bcp14> try all the ACP secure channel protocols it supports and that are feasible because also announced by the candidate ACP neighbor also announced them via its AN_ACP "AN_ACP" GRASP parameters (these are called the "feasible" ACP secure channel protocols).</t>
        <t>To
        <t indent="0" pn="section-6.6-4">To ensure that the selection of the secure channel protocols always succeeds in a predictable fashion without blocking, the following rules apply:
</t>
        <ul spacing="compact">

          <li>An spacing="normal" bare="false" empty="false" indent="3" pn="section-6.6-5">
          <li pn="section-6.6-5.1">An ACP node may choose to attempt to initiate the different feasible ACP secure channel protocols it supports according to its local policies sequentially or in parallel, but it MUST <bcp14>MUST</bcp14> support acting as a responder to all of them in parallel.</li>

          <li>Once
          <li pn="section-6.6-5.2">Once the first ACP secure channel protocol connection to a specific peer IPv6 address passes peer authentication, the two peers know each other's certificate because those ACP certificates are used by all secure channel protocols for mutual authentication.  The peer with the higher Node-ID in the AcpNodeName of its ACP certificate takes on the role of the Decider towards the peer. The other peer takes on the role of the Follower. The Decider selects which secure channel protocol to ultimately use.</li>

          <li>The
          <li pn="section-6.6-5.3">The Follower becomes passive: it does not attempt to further initiate ACP secure channel protocol connections with the Decider and does not consider it to be an error when the Decider closes secure channels.  The Decider becomes the active party, continues continuing to attempt setting up the setup of secure channel protocols with the Follower. This process terminates when the Decider arrives at the "best"
 ACP secure channel connection option that also works with the Follower ("best" from the Deciders Decider's point of view).</li>

<li>A
          <li pn="section-6.6-5.4">A peer with a "0" acp-address in its AcpNodeName takes on the role of Follower when peering with a node that has a non-"0" acp-address (note that this specification does not fully define the behavior of ACP secure channel negotiation for nodes with a "0" ACP address field, it only defines interoperability with such ACP nodes).</li>
        </ul>

        <t>In
        <t indent="0" pn="section-6.6-6">In a simple example, ACP peer Node 1 attempts to initiate an IPsec connection via IKEv2 connection to peer Node 2.  The IKEv2 authentication succeeds. Node 1 has the lower ACP address and becomes the Follower. Node 2 becomes the Decider. IKEv2 might not be the preferred ACP secure channel protocol for the Decider Node 2. Node 2 would therefore proceed to attempt secure channel setups with (in its view) more preferred protocol options (e.g., (in its view, e.g., DTLS/UDP). If any such preferred ACP secure channel connection of the Decider succeeds, it would close the IPsec connection.  If Node 2 has no preferred protocol option over IPsec, or no such connection attempt from Node 2 to Node 1 succeeds, Node 2 would keep the IPsec connection and use it.</t>

<t>The
        <t indent="0" pn="section-6.6-7">The Decider SHOULD NOT <bcp14>SHOULD NOT</bcp14> send actual payload packets across a secure channel until it has decided to use it. The Follower MAY <bcp14>MAY</bcp14> delay linking the ACP secure channel into to the ACP virtual interface until it sees the first payload packet from the Decider up to a maximum of 5 seconds to avoid unnecessarily linking a secure channel that will be terminated as undesired by the Decider shortly afterwards.</t>

        <?rfc needLines="48" ?>
        <t>The afterward.</t>
        <t keepWithNext="true" indent="0" pn="section-6.6-8">The following sequence of steps show this example in more detail. Each step is tagged with [&lt;step#&gt;{:&lt;connection&gt;}]. The connection is included to more easily distinguish which of the two competing connections the step belongs to, one initiated by Node 1, one initiated by Node 2.
        </t>
        <figure anchor="sequence-of-steps">
          <name>Secure Channel sequence of steps</name>
          <artwork name="" type="" align="left" alt=""><![CDATA[
[1]    Node
        <dl newline="false" indent="10" spacing="normal" pn="section-6.6-9">
          <dt pn="section-6.6-9.1">[1]</dt>
          <dd pn="section-6.6-9.2">Node 1 sends GRASP AN_ACP "AN_ACP" message to announce itself

[2]    Node itself.</dd>
          <dt pn="section-6.6-9.3">[2]</dt>
          <dd pn="section-6.6-9.4">Node 2 sends GRASP AN_ACP "AN_ACP" message to announce itself

[3]    Node itself.</dd>
          <dt pn="section-6.6-9.5">[3]</dt>
          <dd pn="section-6.6-9.6">Node 2 receives [1] from Node 1

[4:C1] Because 1.</dd>
          <dt pn="section-6.6-9.7">[4:C1]</dt>
          <dd pn="section-6.6-9.8">Because of [3], Node 2 starts as initiator on its preferred
secure channel protocol towards Node 1. Connection C1.

[5]    Node C1.</dd>
          <dt pn="section-6.6-9.9">[5]</dt>
          <dd pn="section-6.6-9.10">Node 1 receives [2] from Node 2

[6:C2] Because 2.</dd>
          <dt pn="section-6.6-9.11">[6:C2]</dt>
          <dd pn="section-6.6-9.12">Because of [5], Node 1 starts as initiator on its preferred secure channel protocol towards Node 2. Connection C2.

[7:C1] Node1 C2.</dd>
          <dt pn="section-6.6-9.13">[7:C1]</dt>
          <dd pn="section-6.6-9.14">Node 1 and Node2 Node 2 have authenticated each others other's certificate on connection C1 as valid ACP peers.

[8:C1] Node 1 peers.</dd>
          <dt pn="section-6.6-9.15">[8:C1]</dt>
          <dd pn="section-6.6-9.16">Node 1's certificate has a lower ACP Node-ID than Node2, Node 2's, therefore Node 1 considers itself the Follower and Node 2 the Decider on connection C1. Connection setup C1 is completed.

[9]    Node completed.</dd>
          <dt pn="section-6.6-9.17">[9]</dt>
          <dd pn="section-6.6-9.18">Node 1 refrains from attempting any further secure channel connections to Node
2 (the Decider) as learned from [2] because it knows from [8:C1] that it is the Follower relative to Node 1.

[10:C2] Node1 2.
</dd>
          <dt pn="section-6.6-9.19">[10:C2]</dt>
          <dd pn="section-6.6-9.20">Node 1 and Node2 Node 2 have authenticated each others other's certificate on connection C2 (like [7:C1]).

[11:C2] Node 1 [7:C1]).</dd>
          <dt pn="section-6.6-9.21">[11:C2]</dt>
          <dd pn="section-6.6-9.22">Node 1's certificate has a lower ACP Node-ID than Node2, Node 2's, therefore Node 1
considers itself the Follower and Node 2 the Decider on connection C2, but
they also identify that C2 is to the same mutual peer as their C1, so this has
no further impact: the roles Decider and Follower where already assigned
between these two peers by [8:C1].

[12:C2] Node [8:C1].</dd>
          <dt pn="section-6.6-9.23">[12:C2]</dt>
          <dd pn="section-6.6-9.24">Node 2 (the Decider) closes C1. Node 1 is fine with this, because of its role as the Follower (from [8:C1]).

[13]    Node [8:C1]).</dd>
          <dt pn="section-6.6-9.25">[13]</dt>
          <dd pn="section-6.6-9.26">Node 2 (the Decider) and Node 1 (the Follower) start data
transfer across C2, which makes it become a secure channel for the ACP.
        ]]></artwork>
        </figure>

        <t>All ACP.</dd>
        </dl>
        <t indent="0" pn="section-6.6-10">All this negotiation is in the context of an "L2 interface". L2 interface.  The Decider and Follower will build ACP connections to each other on every "L2 interface" L2 interface that they both connect to.  An autonomic node MUST NOT <bcp14>MUST NOT</bcp14> assume that neighbors with the same L2 or link-local IPv6 addresses on different L2 interfaces are the same node.  This can only be determined after examining the certificate after a successful security association attempt.</t>

<t>The
        <t indent="0" pn="section-6.6-11">The Decider SHOULD NOT <bcp14>SHOULD NOT</bcp14> suppress attempting a particular ACP secure channel protocol connection on one L2 interface because this type of ACP secure channel connection has failed to the peer with the same ACP certificate on another L2 interface: Not not only may the supported ACP secure channel protocol options may be different on the same ACP peer across different L2 interfaces, but also error conditions may cause inconsistent failures across different L2 interfaces. Avoiding such connection attempt optimizations can therefore help to increase robustness in the case of errors.</t>
      </section>
      <!-- channel-selection -->
      <section anchor="neighbor_verification" numbered="true" toc="default">
        <name>Candidate toc="include" removeInRFC="false" pn="section-6.7">
        <name slugifiedName="name-candidate-acp-neighbor-veri">Candidate ACP Neighbor verification</name>
        <t>Independent Verification</name>
        <t indent="0" pn="section-6.7-1">Independent of the security association protocol chosen, candidate ACP neighbors need to be authenticated based on their domain certificate.  This implies that any secure channel protocol MUST <bcp14>MUST</bcp14> support certificate based certificate-based authentication that can support the ACP domain membership check as defined in <xref target="certcheck" format="default"/>. format="default" sectionFormat="of" derivedContent="Section 6.2.3"/>.  If it fails, the connection attempt is aborted and an error logged. Attempts to reconnect MUST <bcp14>MUST</bcp14> be throttled. The RECOMMENDED <bcp14>RECOMMENDED</bcp14> default is exponential base 2 base-two backoff with an initial retransmission time (IRT) of 10 seconds and a maximum retransmission time (MRT) of 640 seconds.</t>
        <t>Failure
        <t indent="0" pn="section-6.7-2">Failure to authenticate an ACP neighbor when acting in the role of a responder
of the security authentication protocol MUST NOT <bcp14>MUST NOT</bcp14> impact the attempts of the ACP node
to attempt establishing a connection as an initiator. Only failed connection attempts as
an initiator must cause throttling. This rule is meant to increase resilience
of secure channel creation. <xref target="channel-selection" format="default"/> format="default" sectionFormat="of" derivedContent="Section 6.6"/> shows how simultaneous mutual
secure channel setup collisions are resolved.</t>
      </section>
      <section anchor="associations" numbered="true" toc="default">
        <name>Security toc="include" removeInRFC="false" pn="section-6.8">
        <name slugifiedName="name-security-association-secure">Security Association (Secure Channel) protocols</name>
        <t>This Protocols</name>
        <t indent="0" pn="section-6.8-1">This section describes how ACP nodes establish secured data connections to automatically discovered or configured peers in the ACP. <xref target="discovery-grasp" format="default"/> above described format="default" sectionFormat="of" derivedContent="Section 6.4"/> describes how peers that are adjacent on an IPv6 subnet adjacent peers are discovered automatically. <xref target="remote-acp-neighbors" format="default"/> format="default" sectionFormat="of" derivedContent="Section 8.2"/> describes how non IPv6 subnet adjacent to configure peers can be configured.</t>
        <t><xref that are not adjacent on an IPv6 subnet.</t>
        <t indent="0" pn="section-6.8-2"><xref target="ACP-virtual-interfaces" format="default"/> format="default" sectionFormat="of" derivedContent="Section 6.13.5.2"/> describes how secure channels are mapped to virtual IPv6 subnet interfaces in the ACP. The simple case is to map every ACP secure channel into to a separate ACP point-to-point virtual interface <xref (<xref target="ACP-p2p-virtual-interfaces" format="default"/>. format="default" sectionFormat="of" derivedContent="Section 6.13.5.2.1"/>). When a single subnet has multiple ACP peers peers, this results in multiple ACP point-to-point virtual interfaces across that underlying multi-party multiparty IPv6 subnet. This can be optimized with ACP multi-access virtual interfaces (<xref target="ACP-ma-virtual-interfaces" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 6.13.5.2.2"/>), but the benefits of that optimization may not justify the complexity of that option.</t>
        <section anchor="general-considerations" numbered="true" toc="default">
          <name>General considerations</name>
          <t>Due toc="include" removeInRFC="false" pn="section-6.8.1">
          <name slugifiedName="name-general-considerations">General Considerations</name>
          <t indent="0" pn="section-6.8.1-1">Due to <xref channel selection (<xref target="channel-selection" format="default">Channel Selection</xref>, format="default" sectionFormat="of" derivedContent="Section 6.6"/>), ACP can support an evolving set of security association protocols and does not require support for a single network wide network-wide MTI.  ACP nodes only need to implement those protocols required to interoperate with their candidate peers, not with potentially any node in the ACP domain. See <xref target="Profiles" format="default"/> format="default" sectionFormat="of" derivedContent="Section 6.8.5"/> for an example of this.</t>
          <t>The
          <t indent="0" pn="section-6.8.1-2">The degree of security required on every hop of an ACP network needs to be consistent across the network so that there is no designated "weakest link" because it is that "weakest link" that would otherwise become the designated point of attack. When the secure channel protection on one link is compromised, it can be used to send/receive send and/or receive packets across the whole ACP network. Therefore, even though the security association protocols can be different, their minimum degree of security should be comparable.</t>
          <t>Secure
          <t indent="0" pn="section-6.8.1-3">Secure channel protocols do not need to always support arbitrary L3 Layer 3 (L3) connectivity between peers, but can leverage the fact that the standard use case for ACP secure channels is an L2 adjacency. Hence, L2 dependent mechanisms could be adopted for use as secure channel association protocols:</t>
          <t>L2 protocols.</t>
          <t indent="0" pn="section-6.8.1-4">L2 mechanisms such as strong encrypted radio technologies or <xref target="MACSEC" format="default"/> format="default" sectionFormat="of" derivedContent="MACSEC"/> may offer equivalent encryption encryption, and the ACP security association protocol may only be required to authenticate ACP domain membership of a peer and/or derive a key for the L2 mechanism. Mechanisms that leverage such underlying L2 security to auto-discover and associate ACP peers leveraging such underlying L2 security are possible and desirable to avoid duplication of encryption, but none are specified in this document.</t>
          <t>Strong
          <t indent="0" pn="section-6.8.1-5">Strong physical security of a link may stand in where cryptographic security is infeasible. As there is no secure mechanism to automatically discover strong physical security solely between two peers, it can only be used with explicit configuration configuration, and that configuration too could become an attack vector. This document therefore only specifies with <xref target="ACPconnect" format="default">ACP format="default" sectionFormat="of" derivedContent="Section 8.1">ACP connect</xref> only one explicitly configured mechanism without any secure channel association protocol - for the case where both the link and the nodes attached to it have strong physical security.</t>
        </section>
        <section anchor="common-requirements" numbered="true" toc="default">
          <name>Common requirements</name>
          <t>The toc="include" removeInRFC="false" pn="section-6.8.2">
          <name slugifiedName="name-common-requirements">Common Requirements</name>
          <t indent="0" pn="section-6.8.2-1">The authentication of peers in any security association protocol MUST <bcp14>MUST</bcp14> use the ACP certificate according to <xref target="certcheck" format="default"/>. format="default" sectionFormat="of" derivedContent="Section 6.2.3"/>.  Because auto-discovery of candidate ACP neighbors via GRASP (see <xref target="discovery-grasp" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 6.4"/>) as specified in this document does not communicate the neighbors neighbor's ACP certificate, and ACP nodes may not (yet) have any other network connectivity to retrieve certificates, any security association protocol MUST <bcp14>MUST</bcp14> use a mechanism to communicate the certificate directly instead of relying on a referential mechanism such as communicating only a hash and/or URL for the certificate.</t>
          <t>A
          <t indent="0" pn="section-6.8.2-2">A security association protocol MUST <bcp14>MUST</bcp14> use Forward Secrecy (whether inherently or as part of a profile of the security association protocol). </t>
          <t>Because
          <t indent="0" pn="section-6.8.2-3">Because the ACP payload of legacy protocol payloads inside the ACP and hop-by-hop ACP flooded GRASP information is unencrypted, the ACP secure channel protocol requires confidentiality. Symmetric encryption for the transmission of secure channel data MUST <bcp14>MUST</bcp14> use encryption schemes considered to be security wise equal to or better than 256-bit key strength, such as AES256. AES-256. There MUST NOT <bcp14>MUST NOT</bcp14> be support for NULL encryption. </t>
          <t>Security
          <t indent="0" pn="section-6.8.2-4">Security association protocols typically only signal the End Entity end entity certificate
(e.g.
(e.g., the ACP certificate) and any possible intermediate CA certificates
for successful mutual authentication.  The TA has to be mutually known and
trusted
trusted, and therefore its certificate does not need to be signaled for successful
mutual authentication. Nevertheless, for use with ACP secure channel setup,
there SHOULD <bcp14>SHOULD</bcp14> be the option to include the TA certificate in the signaling
to aid troubleshooting, see <xref target="ta-troubleshoot" format="default"/>.</t>
          <t>Signaling format="default" sectionFormat="of" derivedContent="Section 9.1.1"/>.</t>
          <t indent="0" pn="section-6.8.2-5">Signaling of TA certificates may not be appropriate when the deployment is relying relies on
 a security model where the TA certificate content is considered confidential confidential, and only its hash
is appropriate for signaling. ACP nodes SHOULD <bcp14>SHOULD</bcp14> have a mechanism to select whether
the TA certificate is signaled or not. Assuming not, assuming that both options are possible with
a specific secure channel protocol.</t>
          <t>An
          <t indent="0" pn="section-6.8.2-6">An ACP secure channel MUST <bcp14>MUST</bcp14> immediately be terminated when the lifetime of any certificate in the chain used to authenticate the neighbor expires or becomes revoked.  This may not be standard behavior in secure channel protocols because the certificate authentication may only influence the setup of the secure channel in these protocols, but may not be re-validated revalidated during the lifetime of the secure connection in the absence of this requirement.</t>
          <t>When
          <t indent="0" pn="section-6.8.2-7">When specifying an additional security association protocol for ACP secure channels beyond those covered in this document, any protocol options SHOULD be eliminated that are not necessary to unnecessary for the support of devices that are expected to be able to support the ACP <bcp14>SHOULD</bcp14> be eliminated in order to minimize implementation complexity. For example, definitions for security protocols often include old/inferior old and/or inferior security options required only to interoperate with existing devices that will not be able to cannot update to the currently preferred security options. Such old/inferior old and/or inferior security options do not need to be supported when a security association protocol is first specified for the ACP, thus strengthening the "weakest link" and simplifying ACP implementation overhead.</t>
        </section>
        <section anchor="IPsec-group" numbered="true" toc="default">
          <name>ACP toc="include" removeInRFC="false" pn="section-6.8.3">
          <name slugifiedName="name-acp-via-ipsec">ACP via IPsec</name>
          <t>An
          <t indent="0" pn="section-6.8.3-1">An ACP node announces its ability to support IPsec, negotiated via IKEv2, as the ACP secure channel protocol using the "IKEv2" objective-value 'objective-value' in the "AN_ACP" GRASP objective.</t>
          <t>The
          <t indent="0" pn="section-6.8.3-2">The ACP usage of IPsec and IKEv2 mandates a profile with a narrow set of options of the current standards-track Standards Track usage guidance for IPsec ("<xref target="RFC8221" format="title" sectionFormat="of" derivedContent="Cryptographic Algorithm Implementation Requirements and Usage Guidance for Encapsulating Security Payload (ESP) and Authentication Header (AH)"/>" <xref target="RFC8221" format="default"/> format="default" sectionFormat="of" derivedContent="RFC8221"/>) and IKEv2 ("<xref target="RFC8247" format="title" sectionFormat="of" derivedContent="Algorithm Implementation Requirements and Usage Guidance for the Internet Key Exchange Protocol Version 2 (IKEv2)"/>" <xref target="RFC8247" format="default"/>. format="default" sectionFormat="of" derivedContent="RFC8247"/>).  These option options result in stringent security properties and can exclude deprecated/legacy deprecated and legacy algorithms because there is no need for interoperability with legacy equipment for ACP secure channels.  Any such backward compatibility would lead only to an increased attack surface and implementation complexity, for no benefit.</t>
          <section anchor="IPsec" toc="include" numbered="true">
            <name>Native numbered="true" removeInRFC="false" pn="section-6.8.3.1">
            <name slugifiedName="name-native-ipsec">Native IPsec</name>
            <t>
            <t indent="0" pn="section-6.8.3.1-1"> An ACP node that is supporting native IPsec MUST
	    <bcp14>MUST</bcp14> use IPsec in tunnel mode, negotiated via
	    IKEv2, and with IPv6 payload (e.g., ESP Next Header of 41). It MUST
	    <bcp14>MUST</bcp14> use local and peer link-local IPv6 addresses
	    for encapsulation.  Manual keying MUST NOT <bcp14>MUST NOT</bcp14> be used,
	    see <xref target="domcert" format="default"/>. format="default" sectionFormat="of" derivedContent="Section 6.2"/>. Traffic Selectors
	    are:</t>
            <t>TSi
            <artwork name="" type="" align="left" alt="" pn="section-6.8.3.1-2">
TSi = (0, 0-65535, :: - FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF)</t>
            <t>TSr FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF)
TSr = (0, 0-65535, :: - FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF)</t>
            <t>IPsec FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF)
</artwork>
            <t indent="0" pn="section-6.8.3.1-3">IPsec tunnel mode is required because the ACP will route/forward route and/or forward packets received from any other ACP node across the ACP secure channels, and not only its own generated ACP packets.  With IPsec transport mode (and no additional encapsulation header in the ESP payload), it would only be possible to send packets originated by the ACP node itself because the IPv6 addresses of the ESP must be the same as that of the outer IPv6 header.</t>
            <section anchor="rfc8221req" toc="include" numbered="true">
              <name>RFC8221 numbered="true" removeInRFC="false" pn="section-6.8.3.1.1">
              <name slugifiedName="name-rfc-8221-ipsec-esp">RFC 8221 (IPsec/ESP)</name>
              <t>ACP
              <t indent="0" pn="section-6.8.3.1.1-1">ACP IPsec implementations MUST <bcp14>MUST</bcp14> comply with <xref target="RFC8221" format="default"/> (and its updates). format="default" sectionFormat="of" derivedContent="RFC8221"/> and any specifications that update it. The requirements from above and this section amend and superseded supersede its requirements.</t>
              <t>The
              <t indent="0" pn="section-6.8.3.1.1-2">The IP Authentication Header (AH) MUST NOT <bcp14>MUST NOT</bcp14> be used (because it does not provide confidentiality).</t>
              <t>For
              <t indent="0" pn="section-6.8.3.1.1-3">For the required ESP encryption algorithms in section 5 of <xref target="RFC8221" format="default"/> sectionFormat="of" section="5" format="default" derivedLink="https://rfc-editor.org/rfc/rfc8221#section-5" derivedContent="RFC8221"/>, the following guidance applies:
</t>
              <ul spacing="compact">
                <li>ENCR_NULL spacing="normal" bare="false" empty="false" indent="3" pn="section-6.8.3.1.1-4">
                <li pn="section-6.8.3.1.1-4.1">ENCR_NULL AH MUST NOT <bcp14>MUST NOT</bcp14> be used (because it does not provide confidentiality).</li>
                <li>ENCR_AES_GCM_16
                <li pn="section-6.8.3.1.1-4.2">ENCR_AES_GCM_16 is the only MTI ESP encryption algorithm for ACP via IPsec/ESP (it is already listed as MUST <bcp14>MUST</bcp14> in <xref target="RFC8221" format="default"/>).</li>
                <li>ENCR_AES_CBC format="default" sectionFormat="of" derivedContent="RFC8221"/>).</li>
                <li pn="section-6.8.3.1.1-4.3">ENCR_AES_CBC with AUTH_HMAC_SHA2_256_128 (as the ESP authentication algorithm) and ENCR_AES_CCM_8 MAY <bcp14>MAY</bcp14> be supported. If either provides higher performance than ENCR_AES_GCM_16 ENCR_AES_GCM_16, it SHOULD <bcp14>SHOULD</bcp14> be supported.</li>
                <li>ENCR_CHACHA20_POLY1305 SHOULD
                <li pn="section-6.8.3.1.1-4.4">ENCR_CHACHA20_POLY1305 <bcp14>SHOULD</bcp14> be supported at equal or higher performance than ENCR_AES_GCM_16. If that performance is not feasible, it MAY <bcp14>MAY</bcp14> be supported.</li>
              </ul>
              <t>IKEv2
              <t indent="0" pn="section-6.8.3.1.1-5">IKEv2 indicates an order for the offered algorithms.  The algorithms SHOULD <bcp14>SHOULD</bcp14> be ordered by performance.  The first algorithm supported by both sides is generally chosen.</t>
              <t>
              <t indent="0" pn="section-6.8.3.1.1-6"> Explanations:
</t>
              <ul spacing="compact">
                <li> spacing="normal" bare="false" empty="false" indent="3" pn="section-6.8.3.1.1-7">
                <li pn="section-6.8.3.1.1-7.1">
      There is no requirement to interoperate with legacy equipment in ACP
      secure channels, so a single MTI encryption algorithm for IPsec in ACP
      secure channels is sufficient for interoperability and allows for
      the most lightweight implementations.
    </li>
                <li>
                <li pn="section-6.8.3.1.1-7.2">
      ENCR_AES_GCM_16 is an authenticated encryption Authenticated Encryption with associated data Associated Data (AEAD) cipher
      mode, so no additional ESP authentication algorithm is needed, simplifying
      the MTI requirements of IPsec for the ACP.
    </li>
                <li>There
                <li pn="section-6.8.3.1.1-7.3">There is no MTI requirement for the support of ENCR_AES_CBC because
      ENCR_AES_GCM_16 is assumed to be feasible with less cost/higher cost and/or higher
      performance in modern devices hardware accelerated devices' hardware-accelerated implementations
      compared to ENCR-AES_CBC.
    </li>
                <li>
                <li pn="section-6.8.3.1.1-7.4">
      ENCR_CHACHA20_POLY1305 is mandatory in <xref target="RFC8221" format="default"/> format="default" sectionFormat="of" derivedContent="RFC8221"/> because
      of its target use as a fallback algorithm in case weaknesses in AES are
      uncovered. Unfortunately, there is currently no way to automatically
      propagate across an ACP a policy to disallow use of AES based AES-based algorithms,
      so this target benefit of ENCR_CHACHA20_POLY1305 cannot fully be adopted
      yet for the ACP.  Therefore, this algorithm is only recommended. Changing
      from AES to this algorithm at with a potentially big drop in performance could
      also render the ACP inoperable. Therefore, the there is a performance requirement against
      this algorithm so that it could become an effective security backup to AES
      for the ACP once a policy to switch over to it or prefer it is available in an ACP framework.
    </li>
              </ul>
              <t>
              <t indent="0" pn="section-6.8.3.1.1-8">
  <xref target="RFC8221" format="default"/> format="default" sectionFormat="of" derivedContent="RFC8221"/> allows for 128-bit or 256-bit AES keys.
  This document mandates that only 256-bit AES keys MUST <bcp14>MUST</bcp14> be supported.
</t>
              <t>
              <t indent="0" pn="section-6.8.3.1.1-9">
When <xref target="RFC8221" format="default"/> format="default" sectionFormat="of" derivedContent="RFC8221"/> is updated, ACP implementations will need to
consider legacy interoperability, and the IPsec WG has generally done a very
good job of taking that into account in its recommendations. interoperability.
</t>
            </section>
            <section anchor="rfc4247req" toc="include" numbered="true">
              <name>RFC8247 numbered="true" removeInRFC="false" pn="section-6.8.3.1.2">
              <name slugifiedName="name-rfc-8247-ikev2">RFC 8247 (IKEv2)</name>
              <!-- tte PRF_HMAC_SHA2_512 requirement superseded by requirement for RFC8247, which includes this PRF requirement:

<t>The IKEv2 PRF_HMAC_SHA2_512 pseudorandom function MUST be supported (<xref target="rfc4868"/>).</t>

 -->
              <t>
              <t indent="0" pn="section-6.8.3.1.2-1">
<xref target="RFC8247" format="default"/> format="default" sectionFormat="of" derivedContent="RFC8247"/> provides a baseline recommendation for mandatory to implement mandatory-to-implement ciphers, integrity checks, pseudo-random-functions pseudorandom functions, and Diffie-Hellman mechanisms.
Those recommendations, and the recommendations of subsequent documents documents, apply as well to the ACP.
Because IKEv2 for ACP secure channels is sufficient to be implemented in control plane software, software rather than in ASIC Application-Specific Integrated Circuit (ASIC) hardware, and ACP nodes supporting IKEv2 are not assumed to be code-space code space constrained, and because existing IKEv2 implementations are expected to support <xref target="RFC8247" format="default"/> format="default" sectionFormat="of" derivedContent="RFC8247"/> recommendations, this documents document makes no attempt to simplify its recommendations for use with the ACP.
</t>
              <t>See
              <t indent="0" pn="section-6.8.3.1.2-2">See <xref target="IKEV2IANA" format="default"/> format="default" sectionFormat="of" derivedContent="IKEV2IANA"/> for IANA IKEv2 parameter names used in this text.</t>
              <t>
              <t indent="0" pn="section-6.8.3.1.2-3">
ACP Nodes nodes supporting IKEv2 MUST <bcp14>MUST</bcp14> comply with <xref target="RFC8247" format="default"/> format="default" sectionFormat="of" derivedContent="RFC8247"/> amended by the following requirements requirements, which constitute a policy statement as permitted by <xref target="RFC8247" format="default"/>. format="default" sectionFormat="of" derivedContent="RFC8247"/>.
</t>
              <t>To
              <t indent="0" pn="section-6.8.3.1.2-4">To signal the ACP certificate chain (including TA) as required by <xref target="common-requirements" format="default"/>, format="default" sectionFormat="of" derivedContent="Section 6.8.2"/>, the "X.509 Certificate - Signature" payload in IKEv2 can be used. It is mandatory according to <xref target="RFC7296" format="default"/> section 3.6.</t>
              <t>ACP sectionFormat="comma" section="3.6" format="default" derivedLink="https://rfc-editor.org/rfc/rfc7296#section-3.6" derivedContent="RFC7296"/>.</t>
              <t indent="0" pn="section-6.8.3.1.2-5">ACP nodes SHOULD <bcp14>SHOULD</bcp14> set up IKEv2 to only use the ACP certificate and TA when acting as an IKEv2 responder on the IPv6 link local link-local address and port number indicated in the AN_ACP "AN_ACP" DULL GRASP announcements (see <xref target="discovery-grasp" format="default"/>).</t>
              <t>When format="default" sectionFormat="of" derivedContent="Section 6.4"/>).</t>
              <t indent="0" pn="section-6.8.3.1.2-6">When CERTREQ is received from a peer, and it does not indicate any of this
ACP nodes node's TA certificates, the ACP node SHOULD <bcp14>SHOULD</bcp14> ignore the CERTREQ and
continue sending its certificate chain including its TA as subject to
the requirements and explanations in <xref target="common-requirements" format="default"/>. format="default" sectionFormat="of" derivedContent="Section 6.8.2"/>. This will not result in successful mutual authentication but assists diagnostics.</t>
              <t>Note
              <t indent="0" pn="section-6.8.3.1.2-7">Note that with IKEv2, failing authentication will only result in the responder
receiving the certificate chain from the initiator, but not vice versa. Because
ACP secure channel setup is symmetric (see <xref target="neighbor_verification" format="default"/>), format="default" sectionFormat="of" derivedContent="Section 6.7"/>),
every non-malicious ACP neighbor will attempt to connect as an initiator initiator, though,
allowing it to obtain the diagnostic information about the neighbors neighbor's certificate.</t>

              <t>In
              <t indent="0" pn="section-6.8.3.1.2-8">In IKEv2, ACP nodes are identified by their ACP address. addresses.
The ID_IPv6_ADDR IKEv2 identification payload MUST <bcp14>MUST</bcp14> be used and MUST <bcp14>MUST</bcp14> convey the ACP address.
If the peer's ACP certificate includes a 32HEXDIG ACP address in the acp-node-name (not "0" or omitted), the address in the IKEv2 identification payload MUST <bcp14>MUST</bcp14> match it.
See <xref target="certcheck" format="default"/> format="default" sectionFormat="of" derivedContent="Section 6.2.3"/> for more information about "0" or omitted ACP address fields in the acp-node-name.
</t>
              <t>
              <t indent="0" pn="section-6.8.3.1.2-9">
IKEv2 authentication MUST <bcp14>MUST</bcp14> use authentication method 14 ("Digital Signature") for ACP certificates; this authentication method can be used with both RSA and ECDSA certificates, indicated by an ASN.1 object AlgorithmIdentifier.
</t>
              <t>The
              <t indent="0" pn="section-6.8.3.1.2-10">The Digital Signature hash SHA2-512 MUST <bcp14>MUST</bcp14> be supported (in addition to SHA2-256).</t>
              <t>
              <t indent="0" pn="section-6.8.3.1.2-11">
The IKEv2 Diffie-Hellman key exchange group 19 (256-bit random ECP), MUST <bcp14>MUST</bcp14> be supported.  Reason: ECC provides a similar security level to finite-field (MODP) (modular exponentiation (MODP)) key exchange with a shorter key length, so is generally preferred absent other considerations.
</t>
            </section>
          </section>
          <section anchor="IPsec-GRE" toc="include" numbered="true">
            <name>IPsec numbered="true" removeInRFC="false" pn="section-6.8.3.2">
            <name slugifiedName="name-ipsec-with-gre-encapsulatio">IPsec with GRE encapsulation</name>
            <t>In Encapsulation</name>
            <t indent="0" pn="section-6.8.3.2-1">In network devices devices, it is often more common to implement high performance high-performance virtual interfaces on top of GRE encapsulation than on top of a "native" IPsec association (without any other encapsulation than those defined by IPsec).  On those devices devices, it may be beneficial to run the ACP secure channel on top of GRE protected by the IPsec association.</t>
            <t>The
            <t indent="0" pn="section-6.8.3.2-2">The requirements for ESP/IPsec/IKEv2 with GRE are the same as
	    for native IPsec (see <xref target="IPsec" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 6.8.3.1"/>)
	    except that IPsec transport mode and next protocol GRE (47) are to
	    be negotiated. Tunnel mode is not required because of GRE. Traffic
	    Selectors are:</t>
            <t>TSi
            <artwork name="" type="" align="left" alt="" pn="section-6.8.3.2-3">
TSi = (47, 0-65535, Initiator-IPv6-LL-addr ... Initiator-IPv6-LL-addr)</t>
            <t>TSr Initiator-IPv6-LL-addr)
TSr = (47, 0-65535, Responder-IPv6-LL-addr ... Responder-IPv6-LL-addr)</t>
            <t>If Responder-IPv6-LL-addr)
</artwork>
            <t indent="0" pn="section-6.8.3.2-4">If the IKEv2 initiator and responder support IPsec over GRE, it will be preferred over native IPsec because of the way how IKEv2 negotiates transport mode (as used by this IPsec over GRE profile) versus tunnel mode as used by native IPsec (see <xref target="RFC7296" format="default"/>, section 1.3.1). sectionFormat="of" section="1.3.1" format="default" derivedLink="https://rfc-editor.org/rfc/rfc7296#section-1.3.1" derivedContent="RFC7296"/>).  The ACP IPv6 traffic has to be carried across GRE according to "<xref target="RFC7676" format="title" sectionFormat="of" derivedContent="IPv6 Support for Generic Routing Encapsulation (GRE)"/>" <xref target="RFC7676" format="default"/>.</t> format="default" sectionFormat="of" derivedContent="RFC7676"/>.</t>
          </section>
        </section>
        <!-- IPsec -->
        <section anchor="DTLS" numbered="true" toc="default">
          <name>ACP toc="include" removeInRFC="false" pn="section-6.8.4">
          <name slugifiedName="name-acp-via-dtls">ACP via DTLS</name>

          <t>This
          <t indent="0" pn="section-6.8.4-1">This document defines the use of ACP via DTLS, DTLS on the assumption that it is likely the first transport encryption supported in some classes of constrained devices: DTLS is commonly used in constrained devices when IPsec is not. Code-space Code space on those devices may be also be too limited to support more than the minimum number of required protocols.</t>

          <t>An
          <t indent="0" pn="section-6.8.4-2">An ACP node announces its ability to support DTLS version 1.2 (<xref ("<xref target="RFC6347" format="default"/>) format="title" sectionFormat="of" derivedContent="Datagram Transport Layer Security Version 1.2"/>" <xref target="RFC6347" format="default" sectionFormat="of" derivedContent="RFC6347"/>) compliant with the requirements defined in this document as an ACP secure channel protocol in GRASP through the "DTLS" objective-value 'objective-value' in the "AN_ACP" objective (see <xref target="discovery-grasp" format="default"/>).</t>

          <t>To format="default" sectionFormat="of" derivedContent="Section 6.4"/>).</t>
          <t indent="0" pn="section-6.8.4-3">To run ACP via UDP and DTLS, a locally assigned UDP port is used that is announced as a parameter in the GRASP AN_ACP "AN_ACP" objective to candidate neighbors.  This port can also be any newer version of DTLS as long as that version can negotiate a DTLS v1.2 1.2 connection in the presence of an DTLS v1.2 a peer that only peer.</t>

          <t>All supports DTLS 1.2.</t>
          <t indent="0" pn="section-6.8.4-4">All ACP nodes supporting DTLS as a secure channel protocol MUST <bcp14>MUST</bcp14> adhere to the DTLS implementation recommendations and security considerations of BCP 195, <xref target="RFC7525" format="default">BCP format="default" sectionFormat="of" derivedContent="RFC7525">BCP 195</xref> except with respect to the DTLS version. ACP nodes supporting DTLS MUST <bcp14>MUST</bcp14> support DTLS 1.2. They MUST NOT <bcp14>MUST NOT</bcp14> support older versions of DTLS.</t>

          <t>Unlike
          <t indent="0" pn="section-6.8.4-5">Unlike for IPsec, no attempts are made to simplify the requirements of the BCP 195 recommendations in <xref target="RFC7525" format="default" sectionFormat="of" derivedContent="RFC7525">BCP 195</xref> because the expectation is that DTLS would be using use software-only implementations where the ability to reuse of widely adopted implementations is more important than minimizing the ability to minimize the complexity of a hardware accelerated implementation hardware-accelerated implementation, which is known to be important for IPsec.</t>

          <t>DTLS v1.3 (<xref
          <t indent="0" pn="section-6.8.4-6">DTLS 1.3 <xref target="I-D.ietf-tls-dtls13" format="default"/>) format="default" sectionFormat="of" derivedContent="TLS-DTLS13"/> is "backward compatible" with
DTLS v1.2 1.2 (see section 1. of DTLS v1.3). <xref target="I-D.ietf-tls-dtls13" sectionFormat="of" section="1" format="default" derivedLink="https://tools.ietf.org/html/draft-ietf-tls-dtls13-43#section-1" derivedContent="TLS-DTLS13"/>).  A DTLS implementation supporting both
DTLS v1.2 1.2 and DTLS v1.3 1.3 does comply with the above requirements of negotiating to
DTLS v1.2 1.2 in the presence of a DTLS v1.2 1.2 only peer, but using DTLS v1.3 1.3 when
booth peers support it.</t>

          <t>Version v1.2
          <t indent="0" pn="section-6.8.4-7">Version 1.2 is the MTI version of DTLS in this specification because of the following:
</t>
          <ul spacing="compact">
            <li>There spacing="normal" bare="false" empty="false" indent="3" pn="section-6.8.4-8">
            <li pn="section-6.8.4-8.1">There is more experience with DTLS v1.2 1.2 across the spectrum of target ACP nodes.</li>
            <li>Firmware
            <li pn="section-6.8.4-8.2">Firmware of lower end, lower-end, embedded ACP nodes may not support a newer version for a long time.</li>
            <li>There
            <li pn="section-6.8.4-8.3">There are significant changes of with DTLS v1.3, 1.3, such as a different record layer requiring time to gain implementation and deployment experience especially on lower end, code space lower-end devices with limited devices.</li>
            <li>The code space.</li>
            <li pn="section-6.8.4-8.4">The existing BCP <xref target="RFC7525" format="default"/> format="default" sectionFormat="of" derivedContent="RFC7525"/> for DTLS v1.2 1.2 may equally take an equally longer time to be updated with experience from a newer DTLS version.</li>
            <li>
            <li pn="section-6.8.4-8.5"> There are no significant use-case relevant benefits of DTLS v1.3 1.3 over DTLS v1.2 1.2 that are use-case relevant in the
      context of the ACP options for DTLS. For example, signaling performance improvements for session setup in
      DTLS v1.3 1.3 is not important for the ACP given the long-lived nature of ACP secure channel connections and
      the fact that DTLS connections are mostly link-local link local (short RTT).</li>
          </ul>
          <t>Nevertheless,
          <t indent="0" pn="section-6.8.4-9">Nevertheless, newer versions of DTLS, such as DTLS v1.3 1.3, have stricter security requirements requirements, and the use of the latest standard protocol version is in general recommended for IETF security standards in general recommended. standards. Therefore, ACP implementations are advised to support all the newer versions of DTLS that can still negotiate down to DTLS v1.2.</t>

          <t>[RFC-editor: if by the time of AUTH48, DTLS 1.3 would have evolved to be an RFC, then not only would the references to the DTLS v1.3 draft be changed to the RFC number, but that RFC is then going to be put into the normative list of references and the above paragraph is going to be amended to say: Implementations SHOULD support [DTLSv1.3-RFC]. This is not done right now, because there is no benefit in potentially waiting in RFC-editor queue for that RFC given how the text already lays out a non-normative desire to support DTLSv1.3.]</t>

          <t>There 1.2.</t>
          <t indent="0" pn="section-6.8.4-10">There is no additional session setup or other security association besides this simple DTLS setup.  As soon as the DTLS session is functional, the ACP peers will exchange ACP IPv6 packets as the payload of the DTLS transport connection.  oAny DTLS defined  Any DTLS-defined security association mechanisms such as re-keying rekeying are used as they would be for any transport application relying solely on DTLS.</t>
          <!-- RFC 6125 is a common reference for TLS server-identification/verification procedures, but it covers only names, and only server identities; as such, it's not really a good fit here.  In fact, we can't really do much name validation since the connection is over link-local IPv6 addresses anyway. -->
        </section>
        <!-- DTLS -->
        <section anchor="Profiles" numbered="true" toc="default">
          <name>ACP toc="include" removeInRFC="false" pn="section-6.8.5">
          <name slugifiedName="name-acp-secure-channel-profiles">ACP Secure Channel Profiles</name>
          <t>As
          <t indent="0" pn="section-6.8.5-1">As explained in the beginning of <xref target="channel-selection" format="default"/>, format="default" sectionFormat="of" derivedContent="Section 6.6"/>, there is no single secure channel mechanism mandated for all ACP nodes. Instead, this section defines two ACP profiles (baseline profiles, "baseline" and constrained) "constrained", for ACP nodes that do introduce such requirements.</t>
          <t>An
          <t indent="0" pn="section-6.8.5-2">An ACP node supporting the "baseline" baseline profile MUST <bcp14>MUST</bcp14> support IPsec natively and MAY <bcp14>MAY</bcp14> support IPsec via GRE. An ACP node supporting the "constrained" constrained profile node that cannot support IPsec MUST <bcp14>MUST</bcp14> support DTLS.  An ACP node connecting an area of constrained ACP nodes with an area of baseline ACP nodes needs to support both IPsec and DTLS and supports therefore supports both the baseline and constrained profile.</t>
          <t>Explanation: Not profiles.</t>
          <t indent="0" pn="section-6.8.5-3">Explanation: not all type types of ACP nodes can are able to or need to connect directly to each other or other, nor are they able to support or prefer all possible secure channel mechanisms.  For example, code space limited IoT devices with limited code space may only support DTLS because that code exists already exists on them for end-to-end security, but high-end core routers may not want to support DTLS because they can perform IPsec in accelerated hardware hardware, but they would need to support DTLS in an underpowered CPU forwarding path shared with critical control plane operations. This is not a deployment issue for a single ACP across these type types of nodes as long as there are also appropriate gateway ACP nodes that support sufficiently support many secure channel mechanisms to allow interconnecting areas of ACP nodes with a more constrained set of secure channel protocols. On the edge between IoT areas and high-end core networks, general-purpose routers that act as those gateways and that can support a variety of secure channel protocols is are the norm already.</t>
          <t>IPsec natively
          <t indent="0" pn="section-6.8.5-4">Native IPsec with tunnel mode provides the shortest encapsulation overhead. GRE may be preferred by legacy implementations because because, in the past, the virtual interfaces required by ACP design in conjunction with secure channels have in the past more often been implemented more often for GRE than purely for native IPsec.</t>
          <t>ACP
          <t indent="0" pn="section-6.8.5-5">ACP nodes need to specify in documentation the set of secure ACP mechanisms they support in documentation and should declare which profile they support according to the above requirements.</t>
        </section>
        <!-- Profiles -->
      </section>
      <!-- associations -->
      <section anchor="GRASP" numbered="true" toc="default">
        <name>GRASP toc="include" removeInRFC="false" pn="section-6.9">
        <name slugifiedName="name-grasp-in-the-acp">GRASP in the ACP</name>
        <section anchor="GRASP-core" numbered="true" toc="default">
          <name>GRASP toc="include" removeInRFC="false" pn="section-6.9.1">
          <name slugifiedName="name-grasp-as-a-core-service-of-">GRASP as a core service Core Service of the ACP</name>
          <t>The
          <t indent="0" pn="section-6.9.1-1">The ACP MUST <bcp14>MUST</bcp14> run an instance of GRASP inside of it.  It is a key part of the
        ACP services.  The function in GRASP that makes it fundamental as a service of the ACP
        is the ability to provide ACP wide ACP-wide service discovery (using objectives in GRASP).</t>
          <t>ACP
          <t indent="0" pn="section-6.9.1-2">ACP provides IP unicast routing via the RPL routing protocol (see <xref target="routing" format="default"/>).</t>
          <t>The format="default" sectionFormat="of" derivedContent="Section 6.12"/>).</t>
          <t indent="0" pn="section-6.9.1-3">The ACP does not use IP multicast routing nor does it provide generic IP multicast services
        (the handling of GRASP link-local multicast messages is explained in <xref target="GRASP-substrate" format="default"/>). format="default" sectionFormat="of" derivedContent="Section 6.9.2"/>).
        Instead, the ACP provides service discovery via the objective discovery/announcement and
        negotiation mechanisms of the ACP GRASP instance (services are a form of objectives).
        These mechanisms use hop-by-hop reliable flooding of GRASP messages for both service discovery
        (GRASP M_DISCOVERY messages) and service announcement (GRASP M_FLOOD messages).</t>
          <t>See
          <t indent="0" pn="section-6.9.1-4">See <xref target="acp-grasp" format="default"/> format="default" sectionFormat="of" derivedContent="Appendix A.5"/> for discussion about this design choice
        of the ACP.</t>
        </section>
        <section anchor="GRASP-substrate" numbered="true" toc="default">
          <name>ACP toc="include" removeInRFC="false" pn="section-6.9.2">
          <name slugifiedName="name-acp-as-the-security-and-tra">ACP as the Security and Transport substrate Substrate for GRASP</name>
          <t>In
          <t indent="0" pn="section-6.9.2-1">In the terminology of GRASP (<xref target="I-D.ietf-anima-grasp" format="default"/>), <xref target="RFC8990" format="default" sectionFormat="of" derivedContent="RFC8990"/>, the ACP is the
        security and transport substrate for the GRASP instance run inside the ACP ("ACP GRASP").</t>
          <t>This
          <t indent="0" pn="section-6.9.2-2">This means that the ACP is responsible for ensuring that this instance of GRASP is
        only sending messages across the ACP GRASP virtual interfaces.
        Whenever the ACP adds or deletes such an interface because of new ACP secure channels or
        loss thereof, the ACP needs to indicate this to the ACP instance of GRASP.  The ACP exists
        also in the absence of any active ACP neighbors.  It is created when the node has a domain
        certificate, and it continues to exist even if all of its neighbors cease operation.</t>
          <t>In
          <t indent="0" pn="section-6.9.2-3">In this case case, ASAs using GRASP running on the same node would still need
        to be able to discover each other's objectives.  When the ACP does not exist, ASAs leveraging
        the ACP instance of GRASP via APIs MUST <bcp14>MUST</bcp14> still be able to operate, and MUST they <bcp14>MUST</bcp14> be able to
        understand that there is no ACP and that therefore the ACP instance of GRASP cannot
        operate.</t>
          <t>The following explanation how
          <t indent="0" pn="section-6.9.2-4">How the ACP acts as the security and transport substrate for GRASP is visualized shown
        in <xref target="acp-grasp-picture" format="default"/> below.</t>
          <t>GRASP format="default" sectionFormat="of" derivedContent="Figure 8"/>.</t>
          <t indent="0" pn="section-6.9.2-5">GRASP unicast messages inside the ACP always use the ACP address.  Link-local
        addresses from the ACP VRF MUST NOT <bcp14>MUST NOT</bcp14> be used inside objectives.  GRASP unicast messages inside the ACP
        are transported via TLS. See <xref target="tls" format="default"/> format="default" sectionFormat="of" derivedContent="Section 6.1"/> for TLS requirements.
        TLS mutual authentication MUST <bcp14>MUST</bcp14> use the ACP domain membership check
        defined in (<xref <xref target="certcheck" format="default"/>).</t>

          <t>GRASP format="default" sectionFormat="of" derivedContent="Section 6.2.3"/>.</t>
          <t indent="0" pn="section-6.9.2-6">GRASP link-local multicast messages are targeted for a specific ACP virtual interface
        (as defined <xref target="ACP_interfaces" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 6.13.5"/>), but they are sent by the ACP into to
        an ACP GRASP virtual interface that is constructed from the TCP
        connection(s) to the IPv6 link-local neighbor address(es) on the underlying
        ACP virtual interface.  If the ACP GRASP virtual interface has two or more neighbors,
        the GRASP link-local multicast messages are replicated to all neighbor TCP connections.</t>

          <t>TCP
          <t indent="0" pn="section-6.9.2-7">TCP and TLS connections for GRASP in the ACP use the IANA assigned IANA-assigned TCP port for GRASP (7107).
        Effectively (7017).
        Effectively, the transport stack is expected to be TLS for connections from/to to and from the ACP
        address (e.g., global scope global-scope address(es)) and TCP for connections from/to to and from the link-local addresses
        on the ACP virtual interfaces.  The latter ones are only used for the flooding of GRASP
        messages.</t>
          <!-- https://trac.tools.ietf.org/tools/xml2rfc/trac/ticket/344 -->
          <?rfc needLines="48" ?>
          <figure anchor="acp-grasp-picture">
            <name>ACP anchor="acp-grasp-picture" align="left" suppress-title="false" pn="figure-8">
            <name slugifiedName="name-acp-as-security-and-transpo">ACP as security Security and transport substrate Transport Substrate for GRASP</name>
            <artwork name="" type="" align="left" alt=""><![CDATA[ alt="" pn="section-6.9.2-8.1">
    ..............................ACP..............................
    .                                                             .
    .         /-GRASP-flooding-\         ACP GRASP instance       .
    .        /                  \                                 A
    .    GRASP      GRASP      GRASP                              C
    .  link-local   unicast  link-local                           P
    .   multicast  messages   multicast                           .
    .   messages      |       messages                            .
    .      |          |          |                                .
    ...............................................................
    .      v          v          v    ACP security and transport  .
    .      |          |          |    substrate for GRASP         .
    .      |          |          |                                .
    .      |       ACP GRASP     |       - ACP GRASP              A
    .      |       Loopback       loopback      |         Loopback         loopback interface     C
    .      |       interface     |       - ACP-cert auth          P
    .      |         TLS         |                                .
    .   ACP GRASP     |       ACP GRASP  - ACP GRASP virtual      .
    .   subnet1       |       subnet2      virtual      interfaces             .
    .     TCP         |         TCP                               .
    .      |          |          |                                .
    ...............................................................
    .      |          |          |   ^^^ Users of ACP (GRASP/ASA) .
    .      |          |          |   ACP interfaces/addressing    .
    .      |          |          |                                .
    .      |          |          |                                A
    .      | ACP-Loopback Interf.|      <- ACP Loopback loopback interf.|      &lt;- ACP loopback interface C
    .      |      ACP-address    |       - address (global ULA)   P
    .    subnet1      |        subnet2  <-  &lt;- ACP virtual interfaces .
    .  link-local     |      link-local  - link-local addresses   .
    ...............................................................
    .      |          |          |   ACP VRF                      .
    .      |     RPL-routing     | virtual routing and forwarding .
    .      |   /IP-Forwarding\   |                                A
    .      |  /               \  |                                C
    .  ACP IPv6 packets   ACP IPv6 packets                        P
    .      |/                   \|                                .
    .    IPsec/DTLS        IPsec/DTLS  - ACP-cert auth            .
    ...............................................................
             |                   |   Data-Plane   Data Plane
             |                   |
             |                   |     - ACP secure channel
         link-local        link-local  - encapsulation addresses
           subnet1            subnet2  - Data-Plane data plane interfaces
             |                   |
          ACP-Nbr1            ACP-Nbr2
        ]]></artwork>
</artwork>
          </figure>
          <section anchor="GRASP-discussion" numbered="true" toc="default">
            <name>Discussion</name>
            <t>TCP toc="include" removeInRFC="false" pn="section-6.9.2.1">
            <name slugifiedName="name-discussion">Discussion</name>
            <t indent="0" pn="section-6.9.2.1-1">TCP encapsulation for GRASP M_DISCOVERY and M_FLOOD link local link-local messages is used because
            these messages are flooded across potentially many hops to all ACP nodes nodes, and a single
            link with even temporary packet loss packet-loss issues (e.g., WiFi/Powerline a Wi-Fi or Powerline link) can reduce the
            probability for loss free loss-free transmission so much that applications would want to increase
            the frequency with which they send these messages.  Such shorter periodic retransmission
            of datagrams would result in more traffic and processing overhead in the ACP
            than the hop-by-hop hop-by-hop, reliable retransmission mechanism offered by TCP and duplicate elimination
            by GRASP.</t>
            <t>TLS
            <t indent="0" pn="section-6.9.2.1-2">TLS is mandated for GRASP non-link-local unicast because the ACP secure channel
            mandatory authentication and encryption protects only against attacks from the outside
            but not against attacks from the inside: Compromised compromised ACP members that have (not yet) been
            detected and removed (e.g., via domain certificate revocation / and/or expiry).</t>
            <t>If
            <t indent="0" pn="section-6.9.2.1-3">If GRASP peer connections were to use just TCP, compromised ACP members could
            simply eavesdrop passively on GRASP peer connections for whom which they are on-path ("man in the
            middle" - or MITM) or intercept and modify them. messages.  With TLS, it is not possible to completely
            eliminate problems with compromised ACP members, but attacks are a lot more complex:</t>
            <t>Eavesdropping/spoofing complex.</t>
            <t indent="0" pn="section-6.9.2.1-4">Eavesdropping and/or spoofing by a compromised ACP node is still possible because
            in the model of the ACP and GRASP, the provider and consumer of an objective have
            initially no unique information (such as an identity) about the other side which that
            would allow them to distinguish a benevolent from a compromised peer.  The compromised
            ACP node would simply announce the objective as well, potentially filter the original
            objective in GRASP when it is a MITM and act as an application level application-level proxy.  This of course
            requires that the compromised ACP node understand the semantics of the GRASP negotiation
            to an extent that allows it the compromised node to proxy it the messages without being detected, but in an ACP environment environment,
            this is quite likely public knowledge or even standardized.</t>
            <t>The
            <t indent="0" pn="section-6.9.2.1-5">The GRASP TLS connections are run the same as any other ACP traffic through the ACP
            secure channels.  This leads to double authentication/encryption, authentication and encryption, which has the following
            benefits:</t>
            <ul spacing="compact">
              <li>Secure spacing="normal" bare="false" empty="false" indent="3" pn="section-6.9.2.1-6">
              <li pn="section-6.9.2.1-6.1">Secure channel methods such as IPsec may provide protection against additional
                attacks, for example reset-attacks.</li>
              <li>The example, reset attacks.</li>
              <li pn="section-6.9.2.1-6.2">The secure channel method may leverage hardware acceleration acceleration, and there may be little
                or no gain in eliminating it.</li>
              <li>There is no different
              <li pn="section-6.9.2.1-6.3">The security model for ACP GRASP from is no different than other ACP traffic. Instead,
                there is just another layer of protection against certain attacks from the inside inside,
                which is important due to the role of GRASP in the ACP.</li>
            </ul>
          </section>
        </section>
      </section>
      <!-- GRASPinstances -->
      <section anchor="separation" numbered="true" toc="default">
        <name>Context toc="include" removeInRFC="false" pn="section-6.10">
        <name slugifiedName="name-context-separation">Context Separation</name>
        <t>The
        <t indent="0" pn="section-6.10-1">The ACP is in a separate context from the normal Data-Plane data plane of the node.  This context includes the ACP channels' IPv6 forwarding and routing as well as any required higher layer higher-layer ACP functions.</t>
        <t>In
        <t indent="0" pn="section-6.10-2">In a classical network system, a dedicated VRF is one logical implementation option for the ACP.  If possible allowed by the systems system's software architecture, separation options that minimize shared components are preferred, components, such as a logical container or virtual machine instance. instance, are preferred.  The context for the ACP needs to be established automatically during the bootstrap of a node.  As much as possible possible, it should be protected from being modified unintentionally by ("Data-Plane") (data plane) configuration.</t>
        <t>Context
        <t indent="0" pn="section-6.10-3">Context separation improves security, security because the ACP is not reachable from the Data-Plane data plane routing or forwarding table(s).  Also, configuration errors from the Data-Plane data plane setup do not affect the ACP.</t>
      </section>
      <!-- separation -->
      <section anchor="addressing" numbered="true" toc="default">
        <name>Addressing toc="include" removeInRFC="false" pn="section-6.11">
        <name slugifiedName="name-addressing-inside-the-acp">Addressing inside the ACP</name>
        <t>The
        <t indent="0" pn="section-6.11-1">The channels explained above typically only establish communication between two adjacent nodes.  In order for communication to happen across multiple hops, the autonomic control plane Autonomic Control Plane requires ACP network wide network-wide valid addresses and routing.  Each ACP node creates a Loopback loopback interface with an ACP network wide network-wide unique address (prefix) inside the ACP context (as explained in in <xref target="separation" format="default"/>). format="default" sectionFormat="of" derivedContent="Section 6.10"/>).  This address may be used also in other virtual contexts.</t>
        <t>With
        <t indent="0" pn="section-6.11-2">With the algorithm introduced here, all ACP nodes in the same routing subdomain have the same /48 ULA prefix.  Conversely, ULA global Global IDs from different domains are unlikely to clash, such that two ACP networks can be merged, as long as the policy allows that merge.  See also <xref target="self-healing" format="default"/> format="default" sectionFormat="of" derivedContent="Section 10.1"/> for a discussion on merging domains.</t>
        <t>Links
        <t indent="0" pn="section-6.11-3">Links inside the ACP only use link-local IPv6 addressing, such that each node's ACP only requires one routable address prefix.</t>
        <section anchor="addr-fundamentals" numbered="true" toc="default">
          <name>Fundamental toc="include" removeInRFC="false" pn="section-6.11.1">
          <name slugifiedName="name-fundamental-concepts-of-aut">Fundamental Concepts of Autonomic Addressing</name>
          <ul spacing="compact">
            <li>Usage: Autonomic spacing="normal" bare="false" empty="false" indent="3" pn="section-6.11.1-1">
            <li pn="section-6.11.1-1.1">Usage: autonomic addresses are exclusively used for self-management functions inside a trusted domain.  They are not used for user traffic.  Communications with entities outside the trusted domain use another address space, for example example, a normally managed routable address space (called "Data-Plane" "data plane" in this document).</li>
            <li>Separation: Autonomic
            <li pn="section-6.11.1-1.2">Separation: autonomic address space is used separately from user address space and other address realms.  This supports the robustness requirement.</li>
            <li>Loopback-only: Only
            <li pn="section-6.11.1-1.3">Loopback only: only ACP Loopback loopback interfaces (and potentially those configured for "ACP connect", ACP connect, see <xref target="ACPconnect" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 8.1"/>) carry routable address(es); all other interfaces (called ACP virtual interfaces) only use IPv6 link local link-local addresses.  The usage of IPv6 link local link-local addressing is discussed in "<xref target="RFC7404" format="title" sectionFormat="of" derivedContent="Using Only Link-Local Addressing inside an IPv6 Network"/>" <xref target="RFC7404" format="default"/>.</li>
            <li>Use-ULA: For Loopback format="default" sectionFormat="of" derivedContent="RFC7404"/>.</li>
            <li pn="section-6.11.1-1.4">Use of ULA: for loopback interfaces of ACP nodes, we use ULA with L=1
	   the L bit set to 1 (as defined in section 3.1 of <xref target="RFC4193" format="default"/>). sectionFormat="of" section="3.1" format="default" derivedLink="https://rfc-editor.org/rfc/rfc4193#section-3.1" derivedContent="RFC4193"/>). Note that the random hash for ACP Loopback loopback addresses uses the definition in <xref target="scheme" format="default"/> format="default" sectionFormat="of" derivedContent="Section 6.11.2"/> and not the one of in <xref target="RFC4193" format="default"/> section 3.2.2.</li>
            <li>No sectionFormat="comma" section="3.2.2" format="default" derivedLink="https://rfc-editor.org/rfc/rfc4193#section-3.2.2" derivedContent="RFC4193"/>.</li>
            <li pn="section-6.11.1-1.5">No external connectivity: They the addresses do not provide access to the Internet.  If a node requires further reaching connectivity, it should use another, traditionally managed address addressing scheme in parallel.</li>
            <li>Addresses
            <li pn="section-6.11.1-1.6">Addresses in the ACP are permanent, permanent and do not support temporary addresses as defined in "<xref target="RFC8981" format="title" sectionFormat="of" derivedContent="Temporary Address Extensions for Stateless Address Autoconfiguration in IPv6"/>" <xref target="RFC4941" format="default"/>.</li>
            <li>Addresses target="RFC8981" format="default" sectionFormat="of" derivedContent="RFC8981"/>.</li>
            <li pn="section-6.11.1-1.7">Addresses in the ACP are not considered sensitive on privacy grounds because ACP nodes are not expected to be end-user hosts hosts, and therefore ACP addresses do therefore not represent end-users end users or groups of end-users. end users.  All ACP nodes are in one (potentially federated) administrative domain. They For ACP traffic, the nodes are assumed to be to be either candidate hosts of ACP traffic amongst each other or transit thereof. nodes.  There are no transit nodes less privileged with fewer privileges to know about the identity of other hosts in the ACP.  Therefore, ACP addresses do not need to be pseudo-random pseudorandom as discussed in "<xref target="RFC7721" format="title" sectionFormat="of" derivedContent="Security and Privacy Considerations for IPv6 Address Generation Mechanisms"/>" <xref target="RFC7721" format="default"/>. format="default" sectionFormat="of" derivedContent="RFC7721"/>.  Because they are not propagated to untrusted (non ACP) (non-ACP) nodes and stay within a domain (of trust), we also do not consider them not to be subject to scanning attacks.</li>
          </ul>
          <t>The
          <t indent="0" pn="section-6.11.1-2">The ACP is based exclusively on IPv6 addressing, addressing for a variety of reasons:
          </t>
          <ul spacing="compact">
            <li>Simplicity, reliability spacing="normal" bare="false" empty="false" indent="3" pn="section-6.11.1-3">
            <li pn="section-6.11.1-3.1">Simplicity, reliability, and scale: If if other network layer network-layer protocols were supported, each would have to have its own set of security associations, routing table table, and process, etc.</li>
            <li>Autonomic
            <li pn="section-6.11.1-3.2">Autonomic functions do not require IPv4: Autonomic autonomic functions and autonomic service agents are new concepts.  They can be exclusively built on IPv6 from day one.  There is no need for backward compatibility.</li>
            <li>OAM
            <li pn="section-6.11.1-3.3">OAM protocols do not require IPv4: The the ACP may carry OAM protocols.  All relevant protocols (SNMP, TFTP, SSH, SCP, RADIUS, Diameter, NETCONF ...) NETCONF, etc.) are available in IPv6. See also <xref target="RFC8368" format="default"/> format="default" sectionFormat="of" derivedContent="RFC8368"/> for how ACP could be made to interoperate with IPv4 only IPv4-only OAM.</li>
          </ul>
          <t>Further
          <t indent="0" pn="section-6.11.1-4">Further explanation about the addressing and routing related routing-related reasons for the choice of the autonomous ACP addressing can be found in <xref target="ACP-loopback" format="default"/>.</t> format="default" sectionFormat="of" derivedContent="Section 6.13.5.1"/>.</t>
        </section>
        <section anchor="scheme" numbered="true" toc="default">
          <name>The toc="include" removeInRFC="false" pn="section-6.11.2">
          <name slugifiedName="name-the-acp-addressing-base-sch">The ACP Addressing Base Scheme</name>
          <t>The Base
          <t indent="0" pn="section-6.11.2-1">The ULA addressing base scheme for ACP nodes has the following format:</t>
          <figure anchor="base-addr-scheme">
            <name>ACP anchor="base-addr-scheme" align="left" suppress-title="false" pn="figure-9">
            <name slugifiedName="name-acp-addressing-base-scheme">ACP Addressing Base Scheme</name>
            <artwork name="" type="" align="left" alt=""><![CDATA[ alt="" pn="section-6.11.2-2.1">
  8      40                     2                     78
+--+-------------------------+------+------------------------------+
|fd| hash(routing-subdomain) | Type |     (sub-scheme)             |
+--+-------------------------+------+------------------------------+
        ]]></artwork>
</artwork>
          </figure>
          <t>The
          <t indent="0" pn="section-6.11.2-3">The first 48-bits 48 bits follow the ULA scheme, scheme as defined in <xref target="RFC4193" format="default"/>, format="default" sectionFormat="of" derivedContent="RFC4193"/>, to which a type Type field is added: added.
          </t>
          <ul spacing="compact">
            <li>"fd" identifies
          <dl spacing="normal" newline="false" indent="3" pn="section-6.11.2-4">
            <dt pn="section-6.11.2-4.1">fd:</dt>
            <dd pn="section-6.11.2-4.2">Identifies a locally defined ULA address.</li>
            <li>The 40-bits address.</dd>
            <dt pn="section-6.11.2-4.3">hash(routing-subdomain):</dt>
            <dd pn="section-6.11.2-4.4">
              <t indent="0" pn="section-6.11.2-4.4.1">The 40-bit ULA "global ID" (term Global ID (a term from <xref target="RFC4193" format="default"/>) format="default" sectionFormat="of" derivedContent="RFC4193"/>) for ACP addresses carried in the acp-node-name in the ACP certificates are the first 40-bits 40 bits of the SHA256 SHA-256 hash of the routing subdomain routing-subdomain from the same acp-node-name.  In the example of <xref target="domcert-acpinfo" format="default"/>, format="default" sectionFormat="of" derivedContent="Section 6.2.2"/>, the routing subdomain routing-subdomain is "area51.research.acp.example.com" "area51.research.acp.example.com", and the 40-bits 40-bit ULA "global ID" 89b714f3db.</li>
            <li>When Global ID is 89b714f3db.</t>
              <t indent="0" pn="section-6.11.2-4.4.2">When creating a new routing-subdomain for an existing autonomic network, Autonomic Network, it MUST <bcp14>MUST</bcp14> be ensured, ensured that rsub is selected so the resulting hash of the routing-subdomain does not collide with the hash of any pre-existing preexisting routing-subdomains of the autonomic network. Autonomic Network. This ensures that ACP addresses created by registrars for different routing subdomains do not collide with each other.</li>
            <li>To other.</t>
              <t indent="0" pn="section-6.11.2-4.4.3">To allow for extensibility, the fact that the ULA "global ID" Global ID is a hash of the routing subdomain SHOULD NOT routing-subdomain <bcp14>SHOULD NOT</bcp14> be assumed by any ACP node during normal operations.  The hash function is only executed during the creation of the certificate.  If BRSKI is used, then the BRSKI registrar will create the acp-node-name in response to the EST Certificate Signing Request (CSR) Attribute Attributes Request message sent by the pledge.</li>
            <li>Establishing pledge.</t>
              <t indent="0" pn="section-6.11.2-4.4.4">Establishing connectivity between different ACP ACPs (different acp-domain-name) acp-domain-names) is outside the scope of this specification.
 If it is being done through future extensions, then the rsub of all routing-subdomains across those autonomic networks need Autonomic Networks needs to be selected so that the resulting routing-subdomain hashes do not collide. For example, a large cooperation with its own private TA may want to create different autonomic networks Autonomic Networks that initially should do not be able to connect but where the option to do so should be kept open. When taking this future possibility into account, it is always easy to always select rsub so that no collisions happen.</li>
            <li>Type: This happen.</t>
            </dd>
            <dt pn="section-6.11.2-4.5">Type:</dt>
            <dd pn="section-6.11.2-4.6">This field allows different address addressing sub-schemes.  This addresses the "upgradability" requirement.  Assignment of types for this field will be maintained by IANA.</li>
          </ul>
          <t>The IANA.</dd>
            <dt pn="section-6.11.2-4.7">(sub-scheme):</dt>
            <dd pn="section-6.11.2-4.8">The sub-scheme may imply a range or set of addresses assigned to the node, this node. This is called the ACP address range/set and explained in each sub-scheme.</t>
          <t>Please sub-scheme.</dd>
          </dl>
          <t indent="0" pn="section-6.11.2-5">Please refer to <xref target="acp-registrars" format="default"/> format="default" sectionFormat="of" derivedContent="Section 6.11.7"/> and <xref target="address-spaces" format="default"/> format="default" sectionFormat="of" derivedContent="Appendix A.1"/> for further explanations for why the following Sub-Addressing schemes addressing sub-schemes are used and why multiple are necessary.</t>
          <t>
          <t indent="0" pn="section-6.11.2-6">
          The following summarizes the addressing Sub-Schemes: sub-schemes:
</t>
          <figure anchor="addr-scheme-summary">
            <name>Addressing
          <table anchor="tab-1" align="center" pn="table-1">
            <name slugifiedName="name-addressing-sub-schemes">Addressing Sub-Schemes</name>
            <artwork name="" type=""
            <thead>
              <tr>
                <th align="left" alt=""><![CDATA[
+------+-----------------+-----------+-------------------+
| Type | Name            |F-bit|   Z | V-bits   | Prefix |
+------+-----------------+-----+-----+----------+--------+
| 0x00 | ACP-Zone        | N/A |   0 | 1 bit    | /127   |
+------+-----------------+-----+-----+----------+--------+
| 0x00 | ACP-Manual      | N/A |   1 | N/A      |  /64   |
+------+-----------------+-----+-----+----------+--------+
| 0x01 | ACP-VLong-8     |   0 | N/A | 8 bits   | /120   |
+------+-----------------+-----+-----+----------+--------+
| 0x01 | ACP-VLong-16    |   1 | N/A | 16 bits  | /112   |
+------+-----------------+-----+-----+----------+--------+
| 0x10 | Reserved colspan="1" rowspan="1">Type</th>
                <th align="left" colspan="1" rowspan="1">Name</th>
                <th align="left" colspan="1" rowspan="1">F-bit</th>
                <th align="left" colspan="1" rowspan="1">Z</th>
                <th align="left" colspan="1" rowspan="1">V-bits</th>
                <th align="left" colspan="1" rowspan="1">Prefix</th>
              </tr>
            </thead>
            <tbody>
              <tr>
                <td align="left" colspan="1" rowspan="1">0</td>
                <td align="left" colspan="1" rowspan="1">ACP-Zone</td>
                <td align="left" colspan="1" rowspan="1">N/A</td>
                <td align="left" colspan="1" rowspan="1">0</td>
                <td align="left" colspan="1" rowspan="1">1 bit</td>
                <td align="left" colspan="1" rowspan="1">/127</td>
              </tr>
              <tr>
                <td align="left" colspan="1" rowspan="1">0</td>
                <td align="left" colspan="1" rowspan="1">ACP-Manual</td>
                <td align="left" colspan="1" rowspan="1">N/A</td>
                <td align="left" colspan="1" rowspan="1">1</td>
                <td align="left" colspan="1" rowspan="1">N/A</td>
                <td align="left" colspan="1" rowspan="1">/64</td>
              </tr>
              <tr>
                <td align="left" colspan="1" rowspan="1">1</td>
                <td align="left" colspan="1" rowspan="1">ACP-Vlong-8</td>
                <td align="left" colspan="1" rowspan="1">0</td>
                <td align="left" colspan="1" rowspan="1">N/A</td>
                <td align="left" colspan="1" rowspan="1">8 bits</td>
                <td align="left" colspan="1" rowspan="1">/120</td>
              </tr>
              <tr>
                <td align="left" colspan="1" rowspan="1">1</td>
                <td align="left" colspan="1" rowspan="1">ACP-Vlong-16</td>
                <td align="left" colspan="1" rowspan="1">1</td>
                <td align="left" colspan="1" rowspan="1">N/A</td>
                <td align="left" colspan="1" rowspan="1">16 bits</td>
                <td align="left" colspan="1" rowspan="1">/112</td>
              </tr>
              <tr>
                <td align="left" colspan="1" rowspan="1">2</td>
                <td colspan="5" align="left" rowspan="1">Reserved / For future definition/allocation     |
+------+-----------------+-----+-----+----------+--------+
| 0x11 | Reserved definition/allocation</td>
              </tr>
              <tr>
                <td align="left" colspan="1" rowspan="1">3</td>
                <td colspan="5" align="left" rowspan="1">Reserved / For future definition/allocation     |
+------+-----------------+-----+-----+----------+--------+
  ]]></artwork>
          </figure>
<t>F-Bit definition/allocation</td>
              </tr>
            </tbody>
          </table>
          <t indent="0" pn="section-6.11.2-8">The F-bit (format bit, <xref target="Vlong" format="default" sectionFormat="of" derivedContent="Section 6.11.5"/>) and Z (<xref target="manual-scheme" format="default" sectionFormat="of" derivedContent="Section 6.11.4"/>) are two encoding fields that are explained below for in the Sub-Schemes sections covering
the sub-schemes that introduce/use use them. V-bits is the number
of bits of addresses allocated to the ACP node.
Prefix is the prefix that the ACP node is announcing into the
RPL routing protocol.</t>
RPL.</t>
        </section>
        <!-- base-scheme -->
        <section anchor="zone-scheme" numbered="true" toc="default">
          <name>ACP toc="include" removeInRFC="false" pn="section-6.11.3">
          <name slugifiedName="name-acp-zone-addressing-sub-sch">ACP Zone Addressing Sub-Scheme (ACP-Zone)</name>
          <t>This
          <t indent="0" pn="section-6.11.3-1">This sub-scheme is used when the Type field of the base scheme is 0x00 0 and the Z bit is 0x0.</t> 0.</t>
          <figure anchor="addr-scheme">
            <name>ACP anchor="addr-scheme" align="left" suppress-title="false" pn="figure-10">
            <name slugifiedName="name-acp-zone-addressing-sub-sche">ACP Zone Addressing Sub-Scheme</name>
            <artwork name="" type="" align="left" alt=""><![CDATA[ alt="" pn="section-6.11.3-2.1">

                 64                             64
+-----------------+---+---------++-----------------------------+---+
|  (base scheme)  | Z | Zone-ID ||           Node-ID               |
|                 |   |         || Registrar-ID |   Node-Number| V |
+-----------------+---+---------++--------------+--------------+---+
         50         1     13            48           15          1

                ]]></artwork>

</artwork>
          </figure>
          <t>The
          <t indent="0" pn="section-6.11.3-3">The fields are defined as follows:</t>
          <ul spacing="compact">
            <li>Type: MUST be 0x0.</li>
            <li>Z: MUST
          <dl spacing="normal" newline="false" indent="3" pn="section-6.11.3-4">
            <dt pn="section-6.11.3-4.1">Type:</dt>
            <dd pn="section-6.11.3-4.2">
              <bcp14>MUST</bcp14> be 0x0.</li>
            <li>Zone-ID: 0.</dd>
            <dt pn="section-6.11.3-4.3">Z: </dt>
            <dd pn="section-6.11.3-4.4">
              <bcp14>MUST</bcp14> be 0.</dd>
            <dt pn="section-6.11.3-4.5">Zone-ID:</dt>
            <dd pn="section-6.11.3-4.6"> A value for a network zone.</li>
            <li>Node-ID: A zone.</dd>
            <dt pn="section-6.11.3-4.7">Node-ID:</dt>
            <dd pn="section-6.11.3-4.8">
              <t indent="0" pn="section-6.11.3-4.8.1">A unique value for each node.</li>
          </ul>
          <t>The node.</t>
              <t indent="0" pn="section-6.11.3-4.8.2">The 64-bit Node-ID must be unique across the ACP domain for each node. It is derived and composed as follows:</t>
          <ul spacing="compact">
            <li>Registrar-ID (48-bit): A
              <dl spacing="normal" newline="false" indent="3" pn="section-6.11.3-4.8.3">
                <dt pn="section-6.11.3-4.8.3.1">Registrar-ID (48 bits): </dt>
                <dd pn="section-6.11.3-4.8.3.2">A number unique inside the domain that identifies identifying the ACP registrar which that assigned the Node-ID to the node.  One or more domain-wide unique identifiers of the ACP registrar can be used for this purpose. See <xref target="registrars-unique" format="default"/>.</li>
            <li>Node-Number: Number format="default" sectionFormat="of" derivedContent="Section 6.11.7.2"/>.</dd>
                <dt pn="section-6.11.3-4.8.3.3">Node-Number:</dt>
                <dd pn="section-6.11.3-4.8.3.4"> A number to make the Node-ID unique.  This can be sequentially assigned by the ACP Registrar registrar owning the Registrar-ID.</li>
            <li>V (1-bit): Virtualization bit: 0: Indicates Registrar-ID.</dd>
              </dl>
            </dd>
            <dt pn="section-6.11.3-4.9">V (1 bit):</dt>
            <dd pn="section-6.11.3-4.10">
              <t indent="0" pn="section-6.11.3-4.10.1">Virtualization bit:</t>
              <dl spacing="normal" newline="false" indent="3" pn="section-6.11.3-4.10.2">
                <dt pn="section-6.11.3-4.10.2.1">0:</dt>
                <dd pn="section-6.11.3-4.10.2.2">Indicates the ACP itself ("ACP node base system); 1: Indicates system)</dd>
                <dt pn="section-6.11.3-4.10.2.3">1:</dt>
                <dd pn="section-6.11.3-4.10.2.4">Indicates the optional "host" context on the ACP node (see below).</li>
          </ul>
          <t>In below).</dd>
              </dl>
            </dd>
          </dl>
          <t indent="0" pn="section-6.11.3-5">In the ACP Zone Addressing Sub-Scheme, the ACP address in the certificate has V field as all zero bits.</t>
          <t>The
          <t indent="0" pn="section-6.11.3-6">The ACP address set of the node includes addresses with any Zone-ID value and any V value. No Therefore, no two nodes in the same ACP and the same hash(routing-subdomain)
  can have the same Node-ID, but different Zone-IDs.</t>
          <t>The Virtual Node-ID with the Zone Addressing Sub-Scheme, for
  example, by differing only in their Zone-ID.</t>
          <t indent="0" pn="section-6.11.3-7">The Virtualization bit in this sub-scheme allows the easy addition of the ACP as a component to existing systems without causing problems in the port number space between the services in the ACP and the existing system.  V:0  V=0 is the ACP router (autonomic node base system), V:1 V=1 is the host with pre-existing preexisting transport endpoints on it that could collide with the transport endpoints used by the ACP router.  The ACP host could could, for example example, have a p2p P2P (peer-to-peer) virtual interface with the V:0 V=0 address as its router into to the ACP.  Depending on the software design of ASAs, which is outside the scope of this specification, they may use the V:0 V=0 or V:1 V=1 address.</t>
          <t>The
          <t indent="0" pn="section-6.11.3-8">The location of the V bit(s) at the end of the address allows the announcement of a single prefix for each ACP node.  For example, in a network with 20,000 ACP nodes, this avoid avoids 20,000 additional routes in the routing table.</t>
          <t>It
          <t indent="0" pn="section-6.11.3-9">It is RECOMMENDED <bcp14>RECOMMENDED</bcp14> that only Zone-ID 0 is used unless it is meant to be
                used in conjunction with operational practices for partial/incremental partial or incremental adoption
                of the ACP as described in <xref target="incremental-adoption" format="default"/>.</t>
          <t>Note: format="default" sectionFormat="of" derivedContent="Section 9.4"/>.</t>
          <t indent="0" pn="section-6.11.3-10">Note: Zones and Zone-ID as defined here are not related to <xref target="RFC4007" format="default"/> zones or zone_id. zone_id defined in "<xref target="RFC4007" format="title" sectionFormat="of" derivedContent="IPv6 Scoped Address Architecture"/>" <xref target="RFC4007" format="default" sectionFormat="of" derivedContent="RFC4007"/>. ACP zone addresses are not scoped (reachable (i.e., reachable only from within an RFC4007 zone) a zone as defined by <xref target="RFC4007" format="default" sectionFormat="of" derivedContent="RFC4007"/>) but are reachable across the whole ACP. An RFC4007 A zone_id is a zone index that has only local significance on a node, node <xref target="RFC4007" format="default" sectionFormat="of" derivedContent="RFC4007"/>, whereas an ACP Zone-ID is an identifier for an ACP zone that is unique across that ACP.</t>
        </section>
        <!-- zone-scheme -->
        <section anchor="manual-scheme" numbered="true" toc="default">
          <name>ACP toc="include" removeInRFC="false" pn="section-6.11.4">
          <name slugifiedName="name-acp-manual-addressing-sub-s">ACP Manual Addressing Sub-Scheme (ACP-Manual)</name>
          <t>This
          <t indent="0" pn="section-6.11.4-1">This sub-scheme is used when the Type field of the base scheme is 0x00 0 and the Z bit is 0x1.</t> 1.</t>
          <figure anchor="manual-scheme-pic">
            <name>ACP anchor="manual-scheme-pic" align="left" suppress-title="false" pn="figure-11">
            <name slugifiedName="name-acp-manual-addressing-sub-sc">ACP Manual Addressing Sub-Scheme</name>
            <artwork name="" type="" align="left" alt=""><![CDATA[ alt="" pn="section-6.11.4-2.1">

                64                             64
+---------------------+---+----------++-----------------------------+
|    (base scheme)    | Z | Subnet-ID||     Interface Identifier    |
+---------------------+---+----------++-----------------------------+
         50             1    13

                ]]></artwork>

</artwork>
          </figure>
          <t>The
          <t indent="0" pn="section-6.11.4-3">The fields are defined as follows:
          </t>
          <ul spacing="compact">
            <li>Type: MUST be 0x0.</li>
            <li>Z: MUST
          <dl spacing="normal" newline="false" indent="3" pn="section-6.11.4-4">
            <dt pn="section-6.11.4-4.1">Type:</dt>
            <dd pn="section-6.11.4-4.2">
              <bcp14>MUST</bcp14> be 0.</dd>
            <dt pn="section-6.11.4-4.3">Z:</dt>
            <dd pn="section-6.11.4-4.4">
              <bcp14>MUST</bcp14> be 0x1.</li>
            <li>Subnet-ID: 1.</dd>
            <dt pn="section-6.11.4-4.5">Subnet-ID:</dt>
            <dd pn="section-6.11.4-4.6"> Configured subnet identifier.</li>
            <li>Interface Identifier.</li>
          </ul>
          <t>This identifier.</dd>
            <dt pn="section-6.11.4-4.7">Interface Identifier:</dt>
            <dd pn="section-6.11.4-4.8">Interface identifier according to <xref target="RFC4291" format="default" sectionFormat="of" derivedContent="RFC4291"/>.</dd>
          </dl>
          <t indent="0" pn="section-6.11.4-5">This sub-scheme is meant for the "manual" allocation to subnets where the other addressing schemes cannot be used.  The primary use case is for assignment to ACP connect subnets (see <xref target="NMS" format="default"/>).</t>
          <t>"Manual" format="default" sectionFormat="of" derivedContent="Section 8.1.1"/>).</t>
          <t indent="0" pn="section-6.11.4-6">"Manual" means that allocations of the Subnet-ID need to be done today with pre-existing, preexisting, non-autonomic mechanisms.  Every subnet that uses this addressing sub-scheme needs to use a unique Subnet-ID (unless some anycast setup is done).</t>
          <t>The
          <t indent="0" pn="section-6.11.4-7">The Z bit field was added to distinguish between the Zone addressing Addressing Sub-Scheme and manual addressing sub-schemes the Manual Addressing Sub-Scheme without requiring one more bit in the base scheme and therefore allowing for the Vlong scheme Addressing Sub-Scheme (described below) in <xref target="Vlong" format="default" sectionFormat="of" derivedContent="Section 6.11.5"/>) to have one more bit available.</t>
          <t>Manual addressing sub-scheme
          <t indent="0" pn="section-6.11.4-8">The Manual Addressing Sub-Scheme addresses SHOULD NOT <bcp14>SHOULD NOT</bcp14> be used in ACP certificates. Any node capable to build of building ACP secure channels and is permitted by Registrar registrar policy to participate in building ACP secure channels SHOULD <bcp14>SHOULD</bcp14> receive an ACP address (prefix) from one of the other ACP addressing sub-schemes.  Nodes  A node that cannot or is not capable (or permitted) permitted to participate in ACP secure channels can connect to the ACP via ACP connect interfaces of ACP edge nodes (see <xref target="ACPconnect" format="default"/>), format="default" sectionFormat="of" derivedContent="Section 8.1"/>) without setting up an ACP secure channel. Their Its ACP certificate MUST <bcp14>MUST</bcp14> omit the acp-address field to indicate that their its ACP certificate is only usable for non- ACP non-ACP secure channel authentication, such as end-to-end transport connections across the ACP or Data-Plane.</t>
          <t>Address data plane.</t>
          <t indent="0" pn="section-6.11.4-9">Address management of ACP connect subnets is done using traditional assignment methods and existing IPv6 protocols. See <xref target="ACautoconfig" format="default"/> format="default" sectionFormat="of" derivedContent="Section 8.1.3"/> for details. Therefore, the notion of V-bit many /V-bits multiple addresses assigned to the ACP nodes does not apply to this Sub-Scheme.</t> sub-scheme.</t>
        </section>
        <!-- manual -->
        <section anchor="Vlong" numbered="true" toc="default">
          <name>ACP toc="include" removeInRFC="false" pn="section-6.11.5">
          <name slugifiedName="name-acp-vlong-addressing-sub-sc">ACP Vlong Addressing Sub-Scheme (ACP-VLong-8/ACP-VLong-16</name>
          <t>This (ACP-Vlong-8/ACP-Vlong-16)</name>
          <t indent="0" pn="section-6.11.5-1">This addressing sub-scheme is used when the Type field of the base scheme is 0x01.</t> 1.</t>
          <figure anchor="v8-scheme">
            <name>ACP anchor="v8-scheme" align="left" suppress-title="false" pn="figure-12">
            <name slugifiedName="name-acp-vlong-addressing-sub-sch">ACP Vlong Addressing Sub-Scheme</name>
            <artwork name="" type="" align="left" alt=""><![CDATA[ alt="" pn="section-6.11.5-2.1">

          50                              78
+---------------------++-----------------------------+----------+
|    (base scheme)    ||           Node-ID                      |
|                     || Registrar-ID |F| Node-Number|        V |
+---------------------++--------------+--------------+----------+
          50                46         1   23/15          8/16
                ]]></artwork>
</artwork>
          </figure>
          <t>
          <t indent="0" pn="section-6.11.5-3">
                  This addressing scheme sub-scheme foregoes the Zone-ID field (<xref target="zone-scheme" format="default" sectionFormat="of" derivedContent="Section 6.11.3"/>) to allow
                  for larger, flatter routed networks (e.g., as in IoT) with
                  8421376
                  8,421,376 Node-Numbers (2^23+2^15). (2<sup>23</sup> + 2<sup>15</sup>).  It also allows for up to
                  2^16 (i.e. 65536)
                  2<sup>16</sup> (i.e., 65,536) different virtualized addresses within a
                  node, which could be used to address individual software
                components in an ACP node.
          </t>
          <t>
          <t indent="0" pn="section-6.11.5-4">
                The fields are the same as in the Zone-ID sub-scheme Zone Addressing Sub-Scheme (<xref target="zone-scheme" format="default" sectionFormat="of" derivedContent="Section 6.11.3"/>) with the
                following refinements:</t>
          <ul spacing="compact">
            <li>
                    F: format
          <dl spacing="normal" newline="false" indent="3" pn="section-6.11.5-5">
            <dt pn="section-6.11.5-5.1">
                    F:</dt>
            <dd pn="section-6.11.5-5.2">Format bit.  This bit determines the format of the
                    subsequent bits.
                  </li>
            <li>
                    V: Virtualization
                  </dd>
            <dt pn="section-6.11.5-5.3">
                    V:</dt>
            <dd pn="section-6.11.5-5.4">Virtualization bit: this is a field that is
                    either 8 or 16 bits.  For F=0, it is 8 bits, for F=1
                    it is 16 bits.  The V bits V-bits are assigned by the ACP
                    node.  In the ACP certificate's ACP address <xref (<xref target="domcert-acpinfo" format="default"/>, format="default" sectionFormat="of" derivedContent="Section 6.2.2"/>), the V-bits are always
                    set to 0.
                  </li>
            <li>
                    Registrar-ID:
                  </dd>
            <dt pn="section-6.11.5-5.5">
                    Registrar-ID:</dt>
            <dd pn="section-6.11.5-5.6"> To maximize Node-Number and V, the
                    Registrar-ID is reduced to 46-bits. 46 bits. One or more domain-wide unique identifiers of the ACP registrar can be used for this purpose. See <xref target="registrars-unique" format="default"/>.
                  </li>
            <li>
                    The format="default" sectionFormat="of" derivedContent="Section 6.11.7.2"/>.
                  </dd>
            <dt pn="section-6.11.5-5.7">
                    Node-Number:</dt>
            <dd pn="section-6.11.5-5.8">The Node-Number is unique to each ACP node.  There are
                    two formats for the Node-Number.   When F=0, the
                    node-number
                    Node-Number is 23 bits,  for F=1 F=1, it is 15 bits.
                    Each format of node-number Node-Number is considered to be in a
                    unique number space.
                  </li>
          </ul>
          <t>
                  </dd>
          </dl>
          <t indent="0" pn="section-6.11.5-6">
                  The F=0 bit format addresses are intended to be used for
                  "general purpose" ACP nodes that would potentially have a
                  limited number (&lt; (less than 256) of clients (ASA/Autonomic Functions (ASA and/or autonomic functions
                  or legacy services) of the ACP that require separate
                  V(irtual) addresses.
          </t>
          <t>
          <t indent="0" pn="section-6.11.5-7">
                  The F=1 bit Node-Numbers are intended for
                  ACP nodes that are ACP edge nodes (see <xref target="NMS" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 8.1.1"/>)
                  or that have a large number of clients requiring separate
                  V(irtual) addresses.  For addresses, for example, large SDN controllers with
                  container modular software architecture (see <xref target="software" format="default"/>). format="default" sectionFormat="of" derivedContent="Section 8.1.2"/>).
          </t>
          <t>
          <t indent="0" pn="section-6.11.5-8">
                  In the Vlong addressing sub-scheme, Addressing Sub-Scheme, the ACP address in the
                  certificate has all V field bits as zero.  The ACP address
                  set for the node includes any V value.
          </t>
        </section>
        <!-- Vlong -->
        <section anchor="other-sub-schemes" numbered="true" toc="default">
          <name>Other toc="include" removeInRFC="false" pn="section-6.11.6">
          <name slugifiedName="name-other-acp-addressing-sub-sc">Other ACP Addressing Sub-Schemes</name>
          <t>Before
          <t indent="0" pn="section-6.11.6-1">Before further addressing sub-schemes are defined, experience with the schemes defined here should be collected.  The schemes defined in this document have been devised to allow hopefully a sufficiently flexible setup of ACPs for a variety of situation. situations.  These reasons also lead to the fairly liberal use of address space: The the Zone Addressing Sub-Scheme is intended to enable optimized routing in large networks by reserving bits for Zone-ID's. Zone-IDs.  The Vlong addressing sub-scheme Addressing Sub-Scheme enables the allocation of 8/16-bit of addresses inside individual ACP nodes.  Both address spaces allow distributed, uncoordinated allocation of node addresses by reserving bits for the registrar-ID Registrar-ID field in the address.</t>
        </section>
        <section anchor="acp-registrars" numbered="true" toc="default">
          <name>ACP toc="include" removeInRFC="false" pn="section-6.11.7">
          <name slugifiedName="name-acp-registrars">ACP Registrars</name>
          <t>ACP
          <t indent="0" pn="section-6.11.7-1">ACP registrars are responsible to enroll for enrolling candidate ACP nodes
   with ACP certificates and associated trust anchor(s).  They are also
   responsible that for including an acp-node-name field
is included in the ACP certificate carrying
   certificate. This field carries the ACP domain name and the ACP nodes
   node's ACP address prefix.  This address
prefix is intended to persist unchanged through the lifetime of the
ACP node.</t>
          <t>Because
          <t indent="0" pn="section-6.11.7-2">Because of the ACP addressing sub-schemes, an ACP domain can have
multiple distributed ACP registrars that do not need to coordinate
for address assignment. ACP registrars can also be sub-CAs, in
which case they can also assign ACP certificates without
dependencies against a (shared) TA (except during renewals
of their own certificates).</t>
          <t>ACP
          <t indent="0" pn="section-6.11.7-3">ACP registrars are PKI registration authorities (RA) enhanced with
the handling of the ACP certificate specific certificate-specific fields. They
request certificates for ACP nodes from a Certification Authority CA
through any appropriate mechanism (out of scope in this document,
but this mechanism is required to be BRSKI for ANI registrars). Only nodes that
are trusted to be compliant with the requirements against registrar requirements
described in this section can be given the necessary credentials
to perform this RA function, such as credentials the credential for the BRSKI
connection ACP registrar to connect to the CA for ANI registrars.</t>
as a registrar.</t>
          <section anchor="registrars-protocols" numbered="true" toc="default">
            <name>Use toc="include" removeInRFC="false" pn="section-6.11.7.1">
            <name slugifiedName="name-use-of-brski-or-other-mecha">Use of BRSKI or other Mechanism/Protocols</name>
            <t>Any Other Mechanisms or Protocols</name>
            <t indent="0" pn="section-6.11.7.1-1">Any protocols or mechanisms may be used by ACP registrars, registrars
as long as the resulting ACP certificate and TA certificate(s) allow can be used
by other domain members to perform the ACP domain membership check described in <xref target="certcheck" format="default"/>
with other ACP domain members, format="default" sectionFormat="of" derivedContent="Section 6.2.3"/>,
and meet the acp-node-name meets the ACP addressing
   requirements for its acp-node-name as described further below in this section.</t>
            <t>An the next three sections.</t>
            <t indent="0" pn="section-6.11.7.1-2">An ACP registrar could be a person deciding whether to
enroll a candidate ACP node and then orchestrating the
enrollment of the ACP certificate and associated TA,
using command line or web based web-based commands on the candidate ACP node
and TA to generate and sign the ACP certificate
and configure certificate and TA onto the node.</t>
            <t>The
            <t indent="0" pn="section-6.11.7.1-3">The only currently defined protocol for ACP registrars is BRSKI
(<xref target="I-D.ietf-anima-bootstrapping-keyinfra" format="default"/>).
<xref target="RFC8995" format="default" sectionFormat="of" derivedContent="RFC8995"/>. When BRSKI
is used, the ACP nodes are called ANI nodes, and the ACP registrars
are called BRSKI or ANI registrars.  The BRSKI specification does not define the
handling of the acp-node-name field because the rules
do not depend on BRSKI but apply equally to any protocols/mechanisms protocols or mechanisms that an
ACP registrar may use.</t>
          </section>
          <section anchor="registrars-unique" numbered="true" toc="default">
            <name>Unique toc="include" removeInRFC="false" pn="section-6.11.7.2">
            <name slugifiedName="name-unique-address-prefix-alloc">Unique Address/Prefix allocation</name>
            <t>ACP Allocation</name>
            <t indent="0" pn="section-6.11.7.2-1">ACP registrars MUST NOT <bcp14>MUST NOT</bcp14> allocate ACP address prefixes to ACP nodes
via the acp-node-name that would collide
with the ACP address prefixes of other ACP nodes in the same ACP domain.
This includes both prefixes allocated by the same ACP registrar to
different ACP nodes as well as prefixes allocated by other ACP registrars
for the same ACP domain.</t>
            <t>To
            <t indent="0" pn="section-6.11.7.2-2">To support such unique address allocation, an ACP registrar MUST <bcp14>MUST</bcp14> have
one or more 46-bit identifiers identifiers, called the Registrar-ID, that are unique across the ACP domain which is called the
Registrar-ID. domain.
Allocation of Registrar-ID(s) to an ACP registrar can happen through
OAM mechanisms in conjunction with some database / and/or allocation orchestration.</t>
            <t>ACP
            <t indent="0" pn="section-6.11.7.2-3">ACP registrars running on physical devices with known globally unique
EUI-48 MAC address(es) (EUI stands for "Extended Unique Identifier") can use the lower 46 bits of those address(es)
as unique Registrar-IDs without requiring any external signaling/configuration signaling and/or configuration
(the upper two bits, V and U U, are not uniquely assigned but are functional).
This approach is attractive for distributed, non-centrally administered, lightweight
ACP registrar implementations. There is no mechanism to deduce from a MAC
address itself whether it is actually uniquely assigned. Implementations need
to consult additional offline information before making this assumption. For
example assumption, for
example, by knowing that a particular physical product/MIC-chip product or Network Interface Controller (NIC) chip is
guaranteed to use globally unique assigned EUI-48 MAC address(es).</t>
            <t>When
            <t indent="0" pn="section-6.11.7.2-4">When the candidate ACP device (called Pledge pledge in BRSKI) is to be
enrolled into an ACP domain, the ACP registrar needs to allocate
a unique ACP address to the node and ensure that the ACP certificate
gets a an acp-node-name field (<xref target="domcert-acpinfo" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 6.2.2"/>)
with the appropriate information - information: ACP domain name, ACP domain-name, ACP-address, address,
and so on. If the ACP registrar uses BRSKI, it signals the ACP
acp-node-name field to the Pledge pledge via the EST /csrattrs command CSR Attributes
(see <xref target="I-D.ietf-anima-bootstrapping-keyinfra" format="default"/>,
section 5.9.2 - target="RFC8995" sectionFormat="comma" section="5.9.2" format="default" derivedLink="https://rfc-editor.org/rfc/rfc8995#section-5.9.2" derivedContent="RFC8995"/>, "EST CSR Attributes").</t>
            <t>[RFC-Editor: please update reference to section 5.9.2 accordingly with latest BRSKI draft at time of publishing, or RFC]</t>
          </section>
          <section anchor="registrars-policy" numbered="true" toc="default">
            <name>Addressing toc="include" removeInRFC="false" pn="section-6.11.7.3">
            <name slugifiedName="name-addressing-sub-scheme-polic">Addressing Sub-Scheme Policies</name>
            <t>The
            <t indent="0" pn="section-6.11.7.3-1">The ACP registrar selects for the candidate ACP node a unique
address prefix from an appropriate ACP addressing sub-scheme,
either a zone addressing sub-scheme Zone Addressing Sub-Scheme prefix (see <xref target="zone-scheme" format="default"/>), format="default" sectionFormat="of" derivedContent="Section 6.11.3"/>),
or a Vlong addressing sub-scheme Addressing Sub-Scheme prefix (see <xref target="Vlong" format="default"/>). format="default" sectionFormat="of" derivedContent="Section 6.11.5"/>). The
assigned ACP address prefix encoded in the acp-node-name field
of the ACP certificate indicates to the ACP node its ACP
address information. The sub-addressing scheme addressing sub-scheme indicates the
prefix length: /127 for zone address sub-scheme, the Zone Addressing Sub-Scheme, /120 or /112
for the Vlong address sub-scheme. Addressing Sub-Scheme. The first address of the prefix is the ACP address.
All other addresses in the prefix are for other uses by the ACP node
as described in the zone Zone Addressing Sub-Scheme and Vlong addressing sub scheme Addressing Sub-Scheme sections.
The ACP address prefix itself is then signaled by the ACP node into
the ACP routing protocol (see <xref target="routing" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 6.12"/>) to establish
IPv6 reachability across the ACP.</t>
            <t>The
            <t indent="0" pn="section-6.11.7.3-2">The choice of addressing sub-scheme and prefix-length prefix length in the Vlong address
sub-scheme Addressing
Sub-Scheme is subject to ACP registrar policy. It could be an ACP domain
wide domain-wide
policy, or a per ACP node or per ACP node type policy. For example,
in BRSKI, the ACP registrar is aware of the IDevID certificate of the candidate ACP node,
which typically contains a "serialNumber" attribute in the
subject field distinguished name encoding that is often indicating indicates the node's
vendor and device type type, and it can be used to drive a policy for selecting an appropriate
addressing sub-scheme for the (class of) node(s).</t>
            <t>ACP
            <t indent="0" pn="section-6.11.7.3-3">ACP registrars SHOULD <bcp14>SHOULD</bcp14> default to allocate ACP zone sub-address scheme allocating Zone Addressing Sub-Scheme
addresses with Zone-ID 0.</t>
            <t>ACP
            <t indent="0" pn="section-6.11.7.3-4">ACP registrars that are aware of the IDevID certificate of a candidate ACP device
SHOULD
<bcp14>SHOULD</bcp14> be able to choose the zone Zone vs. Vlong sub-address scheme Addressing Sub-Scheme for
ACP nodes based on the <xref target="X.520" format="default"/> "serialNumber" attribute <xref target="X.520" format="default" sectionFormat="of" derivedContent="X.520"/> in the
subject field distinguished name encoding of the IDevID certificate, for example example,
by the PID (Product Identifier) part part, which identifies the product type,
or by the complete "serialNumber". The PID PID, for example example, could identify
nodes that allow for specialized ASA requiring multiple addresses or for non-autonomic VMs virtual machines (VMs) for
services
services, and those nodes could receive Vlong sub-address scheme Addressing Sub-Scheme ACP addresses.</t>
            <t>In
            <t indent="0" pn="section-6.11.7.3-5">In a simple allocation scheme, an ACP registrar remembers persistently
across reboots its currently used Registrar-ID and and, for each addressing
scheme (Zone with Zone-ID 0, Vlong with /112, Vlong with /120), the
next Node-Number available for allocation allocation, and increases it increases the next Node-Number during successful
enrollment to of an ACP node.  In this simple allocation scheme, the ACP registrar
would not recycle ACP address prefixes from ACP nodes that are no longer used ACP nodes.</t>
            <t>If used.</t>
            <t indent="0" pn="section-6.11.7.3-6">If allocated addresses cannot be remembered by registrars, then
it is necessary to either to use a new value for the Register-ID field
in the ACP addresses, addresses or to determine allocated ACP addresses from by determining the
addresses of reachable ACP nodes, which is not necessarily the set of all ACP nodes.
Non-tracked
Untracked ACP addresses can be reclaimed by revoking
or not renewing their certificates and instead handing out new certificate certificates
with new addresses (for example example, with a new Registrar-ID value). Note that
such strategies may require coordination amongst registrars.</t>
          </section>
          <section anchor="registrars-renewal" numbered="true" toc="default">
            <name>Address/Prefix toc="include" removeInRFC="false" pn="section-6.11.7.4">
            <name slugifiedName="name-address-prefix-persistence">Address/Prefix Persistence</name>
            <t>When
            <t indent="0" pn="section-6.11.7.4-1">When an ACP certificate is renewed or rekeyed via EST or other
mechanisms, the ACP address/prefix in the acp-node-name field
MUST
<bcp14>MUST</bcp14> be maintained unless security issues or violations of the unique
 address assignment requirements exist or are suspected by the ACP registrar.</t>
            <t>ACP
            <t indent="0" pn="section-6.11.7.4-2">ACP address information SHOULD <bcp14>SHOULD</bcp14> be maintained even when the renewing/rekeying renewing and/or rekeying
ACP registrar is not the same as the one that enrolled the prior ACP certificate.
See <xref target="sub-ca" format="default"/> format="default" sectionFormat="of" derivedContent="Section 9.2.4"/> for an example.</t>
            <t>ACP
            <t indent="0" pn="section-6.11.7.4-3">ACP address information SHOULD <bcp14>SHOULD</bcp14> also be maintained even after an ACP
certificate did expire expires or failed. fails. See <xref target="domcert-re-enroll" format="default"/> format="default" sectionFormat="of" derivedContent="Section 6.2.5.5"/>
and <xref target="domcert-failing" format="default"/>.</t> format="default" sectionFormat="of" derivedContent="Section 6.2.5.6"/>.</t>
          </section>
          <section anchor="registrars-further" numbered="true" toc="default">
            <name>Further toc="include" removeInRFC="false" pn="section-6.11.7.5">
            <name slugifiedName="name-further-details">Further Details</name>
            <t><xref
            <t indent="0" pn="section-6.11.7.5-1"><xref target="registrar-considerations" format="default"/> format="default" sectionFormat="of" derivedContent="Section 9.2"/> discusses further informative
details of ACP registrars: What interactions registrars need, what
parameters they require, needed interactions, required
parameters, certificate renewal and limitations, use of sub-CAs on
registrars
registrars, and centralized policy control.</t>
          </section>
        </section>
      </section>
      <!-- addressing -->
      <section anchor="routing" numbered="true" toc="default">
        <name>Routing toc="include" removeInRFC="false" pn="section-6.12">
        <name slugifiedName="name-routing-in-the-acp">Routing in the ACP</name>
        <t>Once
        <t indent="0" pn="section-6.12-1">Once ULA address addresses are set up up, all autonomic entities should run a routing protocol within the autonomic control plane ACP context.  This routing protocol distributes the ULA created in the previous section for reachability.  The use of the autonomic control plane specific ACP-specific context eliminates the probable clash with Data-Plane data plane routing tables and also secures the ACP from interference from the configuration mismatch or incorrect routing updates.</t>
        <t>The
        <t indent="0" pn="section-6.12-2">The establishment of the routing plane and its parameters are automatic and strictly within the confines of the autonomic control plane. ACP.  Therefore, no explicit configuration is required.</t>
        <t>All
        <t indent="0" pn="section-6.12-3">All routing updates are automatically secured in transit as the channels of the ACP are encrypted, and this routing runs only inside the ACP.</t>
        <t>The
        <t indent="0" pn="section-6.12-4">The routing protocol inside the ACP is RPL (<xref <xref target="RFC6550" format="default"/>). format="default" sectionFormat="of" derivedContent="RFC6550"/>.  See <xref target="why-rpl" format="default"/> format="default" sectionFormat="of" derivedContent="Appendix A.4"/> for more details on the choice of RPL.</t>
        <t>RPL
        <t indent="0" pn="section-6.12-5">RPL adjacencies are set up across all ACP channels in the same domain including all its routing subdomains.  See <xref target="domain-usage" format="default"/> format="default" sectionFormat="of" derivedContent="Appendix A.6"/> for more details.</t>
        <section anchor="rpl-profile" numbered="true" toc="default">
          <name>ACP toc="include" removeInRFC="false" pn="section-6.12.1">
          <name slugifiedName="name-acp-rpl-profile">ACP RPL Profile</name>
          <t>The
          <t indent="0" pn="section-6.12.1-1">The following is a description of the RPL profile that ACP nodes need to support by default.  The format of this section is derived from <xref target="I-D.ietf-roll-applicability-template" format="default"/>.</t> format="default" sectionFormat="of" derivedContent="ROLL-APPLICABILITY"/>.</t>
          <section anchor="rpl-summary" numbered="true" toc="default">
            <name>Overview</name>
            <t>RPL toc="include" removeInRFC="false" pn="section-6.12.1.1">
            <name slugifiedName="name-overview">Overview</name>
            <t indent="0" pn="section-6.12.1.1-1">RPL Packet Information (RPI) (RPI), defined in <xref target="RFC6550" format="default"/>, section 11.2 sectionFormat="comma" section="11.2" format="default" derivedLink="https://rfc-editor.org/rfc/rfc6550#section-11.2" derivedContent="RFC6550"/>, defines the
   data packet artefacts artifacts required or beneficial in the forwarding of packets routed by RPL.
   This profile does not use RPI for better compatibility with accelerated hardware
   forwarding planes planes, which most often does do not support the Hop-by-Hop headers used for RPI,
   but also to avoid the overhead of the RPI header on the wire and cost of adding/removing adding and/or removing them.
</t>
            <!--
  Note: Insertion/removal of headers by a (potentially silicon based) ACP
  node would be be necessary when senders/receivers of ACP packets are legacy
  NOC devices connected via ACP connect (see <xref target="NMS"/> to the ACP.
  Their connectivity can be handled in RPL as non-RPL-aware leafs (or "Internet")
  according to the Data-Plane architecture explained in
  <xref target="I-D.ietf-roll-useofrplinfo" />.
-->
            <section anchor="rpl-single-instance" numbered="true" toc="default">
              <name>Single toc="include" removeInRFC="false" pn="section-6.12.1.1.1">
              <name slugifiedName="name-single-instance">Single Instance</name>
              <t>
              <t indent="0" pn="section-6.12.1.1.1-1">
      To avoid the need for RPI, the ACP RPL profile uses a simple destination prefix
      based routing/forwarding table. table based on destination prefix.
      To achieve this, the profiles profile uses only one RPL
      instanceID.  This single instanceID can contain only one Destination Oriented Destination-Oriented
      Directed Acyclic Graph (DODAG), and the routing/forwarding table can therefore
      only calculate a single class of service ("best effort towards the primary NOC/root")
      and cannot create optimized routing paths to accomplish latency or energy goals
      between any two nodes.
              </t>
              <t>
              <t indent="0" pn="section-6.12.1.1.1-2">
      This choice is a compromise. Consider a network that has multiple NOCs in different locations.
      Only one NOC will become the DODAG root. Traffic to and from other NOCs has to be
      sent through the DODAG (shortest path tree) rooted in the primary NOC.
      Depending on topology, this can be an annoyance from a latency point of view of latency
      or from minimizing network path resources, but this is deemed to be acceptable
      given how ACP traffic is "only" network management/control traffic.
      See <xref target="future-rpl" format="default"/> format="default" sectionFormat="of" derivedContent="Appendix A.9.4"/> for more details.</t>
              <t>Using
              <t indent="0" pn="section-6.12.1.1.1-3">Using a single instanceID/DODAG does not introduce a single point of
      failure, as the DODAG will reconfigure itself when it detects Data-Plane data plane
      forwarding failures failures, including choosing a different root when the primary one fails.
              </t>
              <t>The
              <t indent="0" pn="section-6.12.1.1.1-4">The benefit of this profile, especially compared to other IGPs IGPs, is
      that it does not calculate routes for node nodes reachable through the same
      interface as the DODAG root. This RPL profile can therefore scale to
      a much larger number of ACP nodes in the same amount of compute computation and memory
      than other routing protocols.  Especially protocols, especially on nodes that are leafs of the topology
      or those close to those leafs.
              </t>
            </section>
            <section anchor="rpl-convergence" numbered="true" toc="default">
              <name>Reconvergence</name>
              <t> toc="include" removeInRFC="false" pn="section-6.12.1.1.2">
              <name slugifiedName="name-reconvergence">Reconvergence</name>
              <t indent="0" pn="section-6.12.1.1.2-1">
      In RPL profiles where RPL Packet Information (RPI, see RPI (see <xref target="rpl-Data-Plane" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 6.12.1.13"/>) is present,
      it is also used to trigger reconvergence when misrouted, for example looping, packets example, looping packets, which
      are recognized because of their RPI data. This helps to minimize RPL signaling traffic traffic,
      especially in networks without stable topology and slow links.
              </t>
              <t>
              <t indent="0" pn="section-6.12.1.1.2-2">
      The ACP RPL profile instead relies on quick quickly reconverging the DODAG by
      recognizing link state change (down/up) and triggering reconvergence signaling
      as described in <xref target="rpl-dodag-repair" format="default"/>. format="default" sectionFormat="of" derivedContent="Section 6.12.1.7"/>.  Since links in the ACP
      are assumed to be mostly reliable (or have link layer link-layer protection against loss)
      and because there is no stretch according to <xref target="rpl-dodag-repair" format="default"/>, format="default" sectionFormat="of" derivedContent="Section 6.12.1.7"/>,
      loops caused by loss of RPL routing protocol signaling packets should be exceedingly rare.
              </t>
              <t>
              <t indent="0" pn="section-6.12.1.1.2-3">
      In addition, there are a variety of mechanisms possible in RPL to further
      avoid temporary loops RECOMMENDED that are <bcp14>RECOMMENDED</bcp14> to be used for the ACPL ACP RPL profile:
      DODAG Information Objects (DIOs) SHOULD <bcp14>SHOULD</bcp14> be sent 2 two or 3 three times to inform children
      when losing the last parent. The technique in <xref target="RFC6550" format="default"/>
      section 8.2.2.6. sectionFormat="comma" section="8.2.2.6" format="default" derivedLink="https://rfc-editor.org/rfc/rfc6550#section-8.2.2.6" derivedContent="RFC6550"/> (Detaching) SHOULD <bcp14>SHOULD</bcp14> be favored over that in section 8.2.2.5., Section <xref target="RFC6550" sectionFormat="bare" section="8.2.2.5" format="default" derivedLink="https://rfc-editor.org/rfc/rfc6550#section-8.2.2.5" derivedContent="RFC6550"/>
      (Poisoning) because it allows local connectivity. Nodes SHOULD <bcp14>SHOULD</bcp14> select
      more than one parent, at least 3 three if possible, and send Destination Advertisement Objects (DAO)s (DAOs) to all
      of them in parallel.</t>
              <t>
              <t indent="0" pn="section-6.12.1.1.2-4">
      Additionally, failed ACP tunnels can be quickly discovered trough through the
      secure channel protocol mechanisms such as IKEv2 Dead Peer Detection. dead peer detection.
      This can function as a replacement for a Low-power and Lossy Networks' Network's
      (LLN's) Expected Transmission Count (ETX) feature that feature, which is not used
      in this profile.  A failure of an ACP tunnel should immediately signal the RPL
      control plane to pick a different parent.
              </t>
            </section>
          </section>
          <section anchor="rpl-instances" numbered="true" toc="default">
            <name>RPL toc="include" removeInRFC="false" pn="section-6.12.1.2">
            <name slugifiedName="name-rpl-instances">RPL Instances</name>
            <t>Single
            <t indent="0" pn="section-6.12.1.2-1">There is a single RPL instance.  Default  The default RPLInstanceID = is 0.</t>
          </section>
          <section anchor="rpl-storing" numbered="true" toc="default">
            <name>Storing toc="include" removeInRFC="false" pn="section-6.12.1.3">
            <name slugifiedName="name-storing-vs-non-storing-mode">Storing vs. Non-Storing Mode</name>
            <t>RPL
            <t indent="0" pn="section-6.12.1.3-1">The RPL Mode of Operations (MOP): MUST Operation (MOP) <bcp14>MUST</bcp14> support mode 2 - 2, "Storing Mode of Operations
        with no multicast support".  Implementations MAY <bcp14>MAY</bcp14> support mode 3 ("... with multicast support" support") as that is a superset of mode 2). 2.  Note: Root indicates mode in DIO flow.</t>
          </section>
          <section anchor="rpl-dao-policy" numbered="true" toc="default">
            <name>DAO toc="include" removeInRFC="false" pn="section-6.12.1.4">
            <name slugifiedName="name-dao-policy">DAO Policy</name>
            <t>Proactive,
            <t indent="0" pn="section-6.12.1.4-1">The DAO policy is proactive, aggressive DAO state maintenance:</t>
            <ul spacing="compact">
              <li>Use K-flag spacing="normal" bare="false" empty="false" indent="3" pn="section-6.12.1.4-2">
              <li pn="section-6.12.1.4-2.1">Use the 'K' flag in unsolicited DAO indicating to indicate change from previous
               information (to require DAO-ACK).</li>
              <li>Retry
              <li pn="section-6.12.1.4-2.2">Retry such DAO DAO-RETRIES(3) times with DAO-
               ACK_TIME_OUT(256ms) DAO-ACK_TIME_OUT(256ms) in between.</li>
            </ul>
          </section>
          <section anchor="rpl-path-metric" numbered="true" toc="default">
            <name>Path Metric</name>
            <t>Use Hopcount toc="include" removeInRFC="false" pn="section-6.12.1.5">
            <name slugifiedName="name-path-metrics">Path Metrics</name>
            <t indent="0" pn="section-6.12.1.5-1">Use Hop Count according to "<xref target="RFC6551" format="title" sectionFormat="of" derivedContent="Routing Metrics Used for Path Calculation in Low-Power and Lossy Networks"/>" <xref target="RFC6551" format="default"/>. format="default" sectionFormat="of" derivedContent="RFC6551"/>. Note that this is
        solely for diagnostic purposes as it is not used by the objective function.</t> Objective Function.</t>
          </section>
          <section anchor="rpl-objective-function" numbered="true" toc="default">
            <name>Objective toc="include" removeInRFC="false" pn="section-6.12.1.6">
            <name slugifiedName="name-objective-function">Objective Function</name>
            <t>Objective
            <dl indent="3" newline="false" spacing="normal" pn="section-6.12.1.6-1">
              <dt pn="section-6.12.1.6-1.1">Objective Function (OF): Use OF0 (OF):</dt>
              <dd pn="section-6.12.1.6-1.2">Use Objective Function Zero (OF0) ("<xref target="RFC6552" format="title" sectionFormat="of" derivedContent="Objective Function Zero for the Routing Protocol for Low-Power and Lossy Networks (RPL)"/>" <xref target="RFC6552" format="default"/>.
           No use of metric containers.</t>
            <t>rank_factor: Derived format="default" sectionFormat="of" derivedContent="RFC6552"/>).
           Metric containers are not used.</dd>
              <dt pn="section-6.12.1.6-1.3">rank_factor:</dt>
              <dd pn="section-6.12.1.6-1.4">
                <t indent="0" pn="section-6.12.1.6-1.4.1">Derived from link speed:
            &lt;= 100Mbps:
            if less than or equal to 100 Mbps, LOW_SPEED_FACTOR(5), else HIGH_SPEED_FACTOR(1)</t>
            <t>This HIGH_SPEED_FACTOR(1).</t>
                <t indent="0" pn="section-6.12.1.6-1.4.2">This is a simple rank differentiation between typical "low speed"
        or "IoT" IoT links that commonly max out at 100 Mbps and typical
        infrastructure links with speeds of 1 Gbps or higher. Given how
        the path selection for the ACP focusses focuses only on reachability but
        not on path cost optimization, no attempts at finer grained finer-grained path
        optimization are made. </t>
              </dd>
            </dl>
          </section>
          <section anchor="rpl-dodag-repair" numbered="true" toc="default">
            <name>DODAG toc="include" removeInRFC="false" pn="section-6.12.1.7">
            <name slugifiedName="name-dodag-repair">DODAG Repair</name>
            <t>Global Repair: we
            <dl indent="3" newline="false" spacing="normal" pn="section-6.12.1.7-1">
              <dt pn="section-6.12.1.7-1.1">Global Repair:</dt>
              <dd pn="section-6.12.1.7-1.2">We assume stable links and ranks (metrics), so there is
              no need to periodically rebuild the DODAG.  The DODAG version is only
              incremented under catastrophic events (e.g., administrative action).</t>
            <t>Local Repair: As action).</dd>
              <dt pn="section-6.12.1.7-1.3">Local Repair:</dt>
              <dd pn="section-6.12.1.7-1.4">
                <t indent="0" pn="section-6.12.1.7-1.4.1">As soon as link breakage is detected, the ACP node send sends
        a No-Path DAO for all the targets that were reachable only via this link.
        As soon as link repair is detected, the ACP node validates if this link provides
        a better parent.  If so, a new rank is computed by the ACP node node, and it sends a new DIO
        that advertise advertises the new rank.  Then it sends a DAO with a new path sequence about itself.</t>
            <t>When
                <t indent="0" pn="section-6.12.1.7-1.4.2">When using ACP multi-access virtual interfaces, local repair can be
               triggered directly by peer breakage, see <xref target="ACP-ma-virtual-interfaces" format="default"/>.</t>
            <t>stretch_rank: none format="default" sectionFormat="of" derivedContent="Section 6.13.5.2.2"/>.</t>
              </dd>
              <dt pn="section-6.12.1.7-1.5">stretch_rank:</dt>
              <dd pn="section-6.12.1.7-1.6">None provided ("not stretched").</t>
            <t>Data Path Validation: Not used.</t>
            <t>Trickle: stretched").</dd>
              <dt pn="section-6.12.1.7-1.7">Data-Path Validation:</dt>
              <dd pn="section-6.12.1.7-1.8"> Not used.</t> used.</dd>
              <dt pn="section-6.12.1.7-1.9">Trickle:</dt>
              <dd pn="section-6.12.1.7-1.10">Not used.</dd>
            </dl>
          </section>
          <section anchor="rpl-multicast" numbered="true" toc="default">
            <name>Multicast</name>
            <t>Not toc="include" removeInRFC="false" pn="section-6.12.1.8">
            <name slugifiedName="name-multicast">Multicast</name>
            <t indent="0" pn="section-6.12.1.8-1">Multicast is not used yet yet, but it is possible because of the selected mode of operations.</t>
          </section>
          <section anchor="rpl-security" numbered="true" toc="default">
            <name>Security</name>
            <t><xref target="RFC6550" format="default"/> toc="include" removeInRFC="false" pn="section-6.12.1.9">
            <name slugifiedName="name-security">Security</name>
            <t indent="0" pn="section-6.12.1.9-1">RPL security <xref target="RFC6550" format="default" sectionFormat="of" derivedContent="RFC6550"/> is not used, substituted by and ACP security.</t>
            <t>Because security is substituted.</t>
            <t indent="0" pn="section-6.12.1.9-2">Because the ACP links already include provisions for confidentiality and
         integrity protection, their usage at the RPL layer would be redundant, and
         so RPL security is not used.</t>
          </section>
          <section anchor="rpl-p2p" numbered="true" toc="default">
            <name>P2P communications</name>
            <t>Not toc="include" removeInRFC="false" pn="section-6.12.1.10">
            <name slugifiedName="name-p2p-communications">P2P Communications</name>
            <t indent="0" pn="section-6.12.1.10-1">Not used.</t>
          </section>
          <section anchor="rpl-ipv6" numbered="true" toc="default">
            <name>IPv6 address configuration</name>

            <t>Every toc="include" removeInRFC="false" pn="section-6.12.1.11">
            <name slugifiedName="name-ipv6-address-configuration">IPv6 Address Configuration</name>
            <t indent="0" pn="section-6.12.1.11-1">Every ACP node (RPL node) announces an IPv6 prefix covering the addresses assigned to the ACP node via the AcpNodeName.  The prefix length depends on the addressing sub-scheme of the acp-address, /127 for the Zone Addressing Sub-Scheme and /112 or /120 for the Vlong addressing sub-scheme. Addressing Sub-Scheme.  See <xref target="addressing" format="default"/> format="default" sectionFormat="of" derivedContent="Section 6.11"/> for more details.</t>

            <t>Every
            <t indent="0" pn="section-6.12.1.11-2">Every ACP node MUST <bcp14>MUST</bcp14> install a black hole (aka null) route (also known as a null route) if there are unused parts of the ACP address space assigned to the ACP node via its AcpNodeName. This is superseded by longer prefixes assigned to interfaces for the address space actually used by the node.  For example, when the node has an ACP-VLong-8 ACP-Vlong-8 address space, it installs a /120 black hole route. If it then for example only uses the ACP address (first address from the space), for example, it would assign that address via a /128 address prefix to the ACP loopback interface (see <xref target="ACP-loopback" format="default"/>). format="default" sectionFormat="of" derivedContent="Section 6.13.5.1"/>). None of those longer prefixes are announced into RPL.</t>

             <t>For
            <t indent="0" pn="section-6.12.1.11-3">For ACP-Manual address prefixes configured on an ACP node, for example example, for ACP connect subnets (see <xref target="NMS" format="default"/>), format="default" sectionFormat="of" derivedContent="Section 8.1.1"/>), the node announces the /64 subnet prefix.</t>
          </section>
          <section anchor="rpl-admin" numbered="true" toc="default">
            <name>Administrative parameters</name>
            <t>Administrative toc="include" removeInRFC="false" pn="section-6.12.1.12">
            <name slugifiedName="name-administrative-parameters">Administrative Parameters</name>
            <dl indent="3" newline="false" spacing="normal" pn="section-6.12.1.12-1">
              <dt pn="section-6.12.1.12-1.1">Administrative Preference (<xref target="RFC6550" format="default"/>, 3.2.6 – to section="3.2.6" sectionFormat="comma" format="default" derivedLink="https://rfc-editor.org/rfc/rfc6550#section-3.2.6" derivedContent="RFC6550"/> --to become root): Indicated root):</dt>
              <dd pn="section-6.12.1.12-1.2">
                <t indent="0" pn="section-6.12.1.12-1.2.1">The preference is indicated in the DODAGPreference field of DIO message.
                </t>
            <ul spacing="compact">
              <li>Explicit
                <dl indent="3" newline="false" spacing="normal" pn="section-6.12.1.12-1.2.2">
                  <dt pn="section-6.12.1.12-1.2.2.1">Explicitly configured ”root”: 0b100</li>
              <li>ACP "root":</dt>
                  <dd pn="section-6.12.1.12-1.2.2.2"> 0b100</dd>
                  <dt pn="section-6.12.1.12-1.2.2.3">ACP registrar (Default): 0b011</li>
              <li>ACP-connect (non-registrar): 0b010</li>
              <li>Default: 0b001.</li>
            </ul> (default):</dt>
                  <dd pn="section-6.12.1.12-1.2.2.4"> 0b011</dd>
                  <dt pn="section-6.12.1.12-1.2.2.5">ACP connect (non-registrar):</dt>
                  <dd pn="section-6.12.1.12-1.2.2.6"> 0b010</dd>
                  <dt pn="section-6.12.1.12-1.2.2.7">Default:</dt>
                  <dd pn="section-6.12.1.12-1.2.2.8"> 0b001</dd>
                </dl>
              </dd>
            </dl>
          </section>
          <section anchor="rpl-Data-Plane" numbered="true" toc="default">
            <name>RPL toc="include" removeInRFC="false" pn="section-6.12.1.13">
            <name slugifiedName="name-rpl-packet-information">RPL Packet Information</name>
            <t>RPI
            <t indent="0" pn="section-6.12.1.13-1">RPI is not required in the ACP RPL profile for the following reasons.
            </t>
            <t>One
            <t indent="0" pn="section-6.12.1.13-2">One RPI option is the RPL Source Routing Header (SRH) ("<xref target="RFC6554" format="title" sectionFormat="of" derivedContent="An IPv6 Routing Header for Source Routes with the Routing Protocol for Low-Power and Lossy Networks (RPL)"/>" <xref target="RFC6554" format="default"/> format="default" sectionFormat="of" derivedContent="RFC6554"/>), which is not
           necessary because the ACP RPL profile uses storing mode where each hop has the necessary next-hop
           forwarding information.</t>
            <t>The
            <t indent="0" pn="section-6.12.1.13-3">The simpler RPL Option header "<xref target="RFC6553" format="title" sectionFormat="of" derivedContent="The Routing Protocol for Low-Power and Lossy Networks (RPL) Option for Carrying RPL Information in Data-Plane Datagrams"/>" <xref target="RFC6553" format="default"/> format="default" sectionFormat="of" derivedContent="RFC6553"/> is also
           not necessary in this profile, because it uses a single RPL instance and data path data-path
           validation is also not used.</t>
          </section>
          <section anchor="rpl-unknown" numbered="true" toc="default">
            <name>Unknown toc="include" removeInRFC="false" pn="section-6.12.1.14">
            <name slugifiedName="name-unknown-destinations">Unknown Destinations</name>
            <t>Because
            <t indent="0" pn="section-6.12.1.14-1">Because RPL minimizes the size of the routing and forwarding table, prefixes reachable through the same interface as the RPL root are not known on every ACP node.  Therefore, traffic to unknown destination addresses can only be discovered at the RPL root.  The RPL root SHOULD <bcp14>SHOULD</bcp14> have attach safe attach-safe mechanisms to operationally discover and log such packets.</t>

            <t>As
            <t indent="0" pn="section-6.12.1.14-2">As this requirement places additional constraints on the Data-Plane data plane
              functionality of the RPL root, it does not apply to "normal" nodes
              that are not configured to have special functionality (i.e., the
              administrative parameter from <xref target="rpl-admin" format="default"/> format="default" sectionFormat="of" derivedContent="Section 6.12.1.12"/> has value 0b001).
              If the ACP network is degraded to the point where there are no nodes that
              could be configured as root, registrar, or ACP-connect ACP connect nodes, it is
              possible that the RPL root (and thus the ACP as a whole) would be
              unable to detect traffic to unknown destinations.  However, in the
              absence of nodes with administrative preference other than 0b001,
              there is also unlikely to be a way to get diagnostic information out
              of the ACP, so detection of traffic to unknown destinations would not
              be actionable anyway.
            </t>
          </section>
        </section>
        <!-- rpl -->
      </section>
      <!-- routing -->
      <section anchor="acp_general" numbered="true" toc="default">
        <name>General toc="include" removeInRFC="false" pn="section-6.13">
        <name slugifiedName="name-general-acp-considerations">General ACP Considerations</name>
        <t>Since
        <t indent="0" pn="section-6.13-1">Since channels are by default established between adjacent neighbors, neighbors by default, the resulting overlay network does hop-by-hop encryption.  Each node decrypts incoming traffic from the ACP, ACP and encrypts outgoing traffic to its neighbors in the ACP.  Routing is discussed in <xref target="routing" format="default"/>.</t> format="default" sectionFormat="of" derivedContent="Section 6.12"/>.</t>
        <section anchor="performance" numbered="true" toc="default">
          <name>Performance</name>
          <t>There toc="include" removeInRFC="false" pn="section-6.13.1">
          <name slugifiedName="name-performance">Performance</name>
          <t indent="0" pn="section-6.13.1-1">There are no performance requirements against for ACP implementations defined in this document because the performance requirements depend on the intended use case.  It is expected that full a fully autonomic node with a wide range of ASA can require high forwarding plane performance in the ACP, for example example, for telemetry.  Implementations of ACP to that solely support traditional/SDN style traditional or SDN-style use cases can benefit from ACP at lower performance, especially if the ACP is used only for critical operations, e.g., when the Data-Plane data plane is not available. The design of the ACP as specified in this document is intended to support a wide range of performance options: It it is intended to allow software-only implementations at potentially low performance, but the design can also support high performance high-performance options. See <xref target="RFC8368" format="default"/> format="default" sectionFormat="of" derivedContent="RFC8368"/> for more details.</t>
        </section>
        <!-- performance -->
        <section anchor="general_addressing" numbered="true" toc="default">
          <name>Addressing toc="include" removeInRFC="false" pn="section-6.13.2">
          <name slugifiedName="name-addressing-of-secure-channe">Addressing of Secure Channels</name>
          <t>In
          <t indent="0" pn="section-6.13.2-1">In order to be independent of the Data-Plane data plane routing and addressing,
the GRASP discovered ACP secure channels discovered via GRASP use IPv6 link local link-local addresses between
adjacent neighbors.  Note: <xref target="remote-acp-neighbors" format="default"/> format="default" sectionFormat="of" derivedContent="Section 8.2"/> specifies
extensions in which secure channels are configured tunnels operating over
the Data-Plane, data plane, so those secure channels cannot be independent of the
Data-Plane.</t>
          <t>To
data plane.</t>
          <t indent="0" pn="section-6.13.2-2">To avoid that Data-Plane configuration can impact impacting the operations of the
IPv6 (link-local) interface/address used for ACP channels, channels when configuring the data plane, appropriate
implementation considerations are required. If the IPv6 interface/link-local
address is shared with the Data-Plane, data plane, it needs to be impossible to unconfigure/disable unconfigure and/or disable
it through configuration. Instead of sharing the IPv6 interface/link-local
address, a separate (virtual) interface with a separate IPv6 link-local
address can be used. For example, the ACP interface could be run over a separate
MAC address of an underlying L2 (Ethernet) interface.  For more details and options,
see <xref target="dp-dependency" format="default"/>.</t>
          <t>Note format="default" sectionFormat="of" derivedContent="Appendix A.9.2"/>.</t>
          <t indent="0" pn="section-6.13.2-3">Note that other (non-ideal) (nonideal) implementation choices may introduce additional additional, undesired
dependencies against the Data-Plane. For data plane, for example, shared code and configuration
of the secure channel protocols (IPsec / and/or DTLS).</t>
        </section>
        <section anchor="general_MTU" numbered="true" toc="default">
          <name>MTU</name>
          <t>The toc="include" removeInRFC="false" pn="section-6.13.3">
          <name slugifiedName="name-mtu">MTU</name>
          <t indent="0" pn="section-6.13.3-1">The MTU for ACP secure channels MUST <bcp14>MUST</bcp14> be derived locally from the underlying link MTU minus the secure channel encapsulation overhead.</t>
          <t>ACP
          <t indent="0" pn="section-6.13.3-2">ACP secure Channel channel protocols do not need to perform MTU discovery because they are built across L2 adjacencies - adjacencies: the MTU MTUs on both sides connecting to the L2 connection are assumed to be consistent.  Extensions to ACP where the ACP is is, for example example, tunneled need to consider how to guarantee MTU consistency.  This is an issue of tunnels, not an issue of running the ACP across a tunnel.  Transport stacks running across ACP can perform normal PMTUD (Path MTU Discovery).  Because the ACP is meant to prioritize reliability over performance, they MAY <bcp14>MAY</bcp14> opt to only expect IPv6 minimum MTU (1280) (1280 octets) to avoid running into PMTUD implementation bugs or underlying link MTU mismatch problems.</t>
        </section>
        <section anchor="general_multipath" numbered="true" toc="default">
          <name>Multiple links toc="include" removeInRFC="false" pn="section-6.13.4">
          <name slugifiedName="name-multiple-links-between-node">Multiple Links between nodes</name>
          <t>If Nodes</name>
          <t indent="0" pn="section-6.13.4-1">If two nodes are connected via several links, the ACP SHOULD <bcp14>SHOULD</bcp14> be established across every link, but it is possible to establish the ACP only on a sub-set subset of links.  Having an ACP channel on every link has a number of advantages, for example example, it allows for a faster failover in case of link failure, and it reflects the physical topology more closely.  Using a subset of links (for example, a single link), reduces resource consumption on the node, node because state needs to be kept per ACP channel.  The negotiation scheme explained in <xref target="channel-selection" format="default"/> format="default" sectionFormat="of" derivedContent="Section 6.6"/> allows the Decider (the node with the higher ACP address) to drop all but the desired ACP channels to the Follower - Follower, and the Follower will not re-try retry to build these secure channels from its side unless the Decider shows up appears with a previously unknown GRASP announcement (e.g., on a different link or with a different address announced in GRASP).</t>
        </section>
        <!-- multiple_interfaces -->
        <section anchor="ACP_interfaces" numbered="true" toc="default">
          <name>ACP interfaces</name>
          <t>The toc="include" removeInRFC="false" pn="section-6.13.5">
          <name slugifiedName="name-acp-interfaces">ACP Interfaces</name>
          <t indent="0" pn="section-6.13.5-1">Conceptually, the ACP VRF has conceptually two type types of interfaces: The the "ACP Loopback loopback
        interface(s)" to which the ACP ULA address(es) are assigned and the
         "ACP virtual interfaces" that are mapped to the ACP secure channels.</t>
          <section anchor="ACP-loopback" numbered="true" toc="default">
            <name>ACP loopback interfaces</name>
            <t>For toc="include" removeInRFC="false" pn="section-6.13.5.1">
            <name slugifiedName="name-acp-loopback-interfaces">ACP Loopback Interfaces</name>
            <t indent="0" pn="section-6.13.5.1-1">For autonomous operations of the ACP, as described in <xref target="self-creation" format="default"/> format="default" sectionFormat="of" derivedContent="Section 6"/>
        and <xref target="acp-l2-switches" format="default"/>, format="default" sectionFormat="of" derivedContent="Section 7"/>, the ACP node uses the first address from
        the N bit ACP prefix (N assigned to the node. N = 128 (128 - number of Vbits of the ACP address) assigned to the node. address).
        This address is assigned with an address prefix of N or larger to a loopback interface.</t>
            <t>Other
            <t indent="0" pn="section-6.13.5.1-2">Other addresses from the prefix can be used by the ACP of the node as desired.
        The autonomous operations of the ACP does do not require additional global scope global-scope
         IPv6 addresses, they are instead intended for ASA or non-autonomous functions.
        Non fully autonomic components
        Components of the ACP that are not fully autonomic, such as ACP connect interfaces
        (see <xref target="acp-connect" format="default"/>) format="default" sectionFormat="of" derivedContent="Figure 14"/>), may also introduce additional
        global scope
        global-scope IPv6 addresses on other types of interfaces into the ACP.</t>
            <t>[RFC-Editor: please remove this paragraph: Note to reviewers:
        Please do not complain again about an obsolete RFC number in the following paragraph. The text should
        make it clear that the reference was chosen to indicate a particular point in time,
        but not to recommend/use a particularly obsolete protocol spec.]</t>
            <t>The ACP.</t>
            <t indent="0" pn="section-6.13.5.1-3">The use of loopback interfaces for global scope global-scope addresses is
        common operational configuration practice on routers, for example example, in IBGP Internal BGP (IBGP)
        connections since BGP4 (see "<xref target="RFC1654" format="title" sectionFormat="of" derivedContent="A Border Gateway Protocol 4 (BGP-4)"/>" <xref target="RFC1654" format="default"/>) format="default" sectionFormat="of" derivedContent="RFC1654"/>) or earlier.
        The ACP adopts and automates this operational practice.</t>
            <t>A
            <t indent="0" pn="section-6.13.5.1-4">A loopback interface for use with the ACP as described above is an interface
        behaving
        that behaves according to Section <xref target="RFC6724" format="default"/> Section 4., paragraph 2: section="4" sectionFormat="bare" format="default" derivedLink="https://rfc-editor.org/rfc/rfc6724#section-4" derivedContent="RFC6724"/> of <xref target="RFC6724" format="default" sectionFormat="of" derivedContent="RFC6724">"Default Address Selection for Internet Protocol Version 6 (IPv6)"</xref>, paragraph 2.
        Packets sent by the host of the node from the loopback interface
        behave as if they are looped back by the interface so that
        they look as if they originated from the loopback interface, are
        then received by the node and forwarded by it towards the destination.</t>
            <t>The word loopback only
            <t indent="0" pn="section-6.13.5.1-5">The term "loopback only" indicates this behavior, but not the actual name of the
        interface type choosen chosen in an actual implementation.
        A loopback interface for use with the ACP can be a virtual/software virtual and/or software
        construct without any associated hardware, or it can be a hardware interface
        operating in loopback mode.</t>
            <t>A
            <t indent="0" pn="section-6.13.5.1-6">A loopback interface used for the ACP MUST NOT <bcp14>MUST NOT</bcp14> have connectivity to other
        nodes.</t>
            <t>The
            <t indent="0" pn="section-6.13.5.1-7">The following list reviews the reasons for the choice of loopback addresses
        for ACP addresses addresses, which is based on the IPv6 address architecture and common challenges:
            </t>
            <ol type="1" spacing="compact">
              <li>IPv6 spacing="normal" indent="adaptive" start="1" pn="section-6.13.5.1-8">
              <li pn="section-6.13.5.1-8.1" derivedCounter="1.">IPv6 addresses are assigned to interfaces, not nodes. IPv6 continues
          the IPv4 model that a subnet prefix is associated with one link,
          see Section <xref target="RFC4291" format="default"/>, Section 2.1.</li>
              <li>IPv6 section="2.1" sectionFormat="bare" format="default" derivedLink="https://rfc-editor.org/rfc/rfc4291#section-2.1" derivedContent="RFC4291"/> of <xref target="RFC4291" format="default" sectionFormat="of" derivedContent="RFC4291">"IP Version 6 Addressing Architecture"</xref>.</li>
              <li pn="section-6.13.5.1-8.2" derivedCounter="2.">IPv6 implementations commonly do not allow assignment of the same
              IPv6 global scope global-scope address in the same VRF to more
          than one interface.</li>
              <li>Global scope
              <li pn="section-6.13.5.1-8.3" derivedCounter="3.">Global-scope addresses assigned to interfaces that are connecting connect to other
          nodes (external interfaces) may not be stable addresses for communications
          because any such interface could fail due to reasons external to the node.
          This could render the addresses assigned to that interface unusable.</li>
              <li>If
              <li pn="section-6.13.5.1-8.4" derivedCounter="4.">If failure of the subnet does not result in bringing bring down the interface and making make
          the addresses unusable, it could result in unreachability of the
          address because the shortest path to the node might go through one of the
          other nodes on the same subnet subnet, which could equally consider the subnet to
          be operational even though it is not.</li>
              <li>Many
              <li pn="section-6.13.5.1-8.5" derivedCounter="5.">Many OAM service implementations on routers cannot deal with more than one peer address,
          often because they do already expect that a single loopback address can be used,
          especially to provide a stable address under failure of external interfaces or links.</li>
              <li>Even
              <li pn="section-6.13.5.1-8.6" derivedCounter="6.">Even when an application supports multiple addresses to a peer, it
          can only use one address for a connection at a time for a connection with the most widely deployed
          transport protocols protocols, TCP and UDP. While "<xref target="RFC6824" format="title" sectionFormat="of" derivedContent="TCP Extensions for Multipath Operation with Multiple Addresses"/>" <xref target="RFC6824" format="default"/> format="default" sectionFormat="of" derivedContent="RFC6824"/>/<xref target="RFC8684" format="default" sectionFormat="of" derivedContent="RFC8684"/> solves this problem,
          it is not widely adopted for by implementations of router OAM services implementations.</li>
              <li>To services.</li>
              <li pn="section-6.13.5.1-8.7" derivedCounter="7.">To completely autonomously assign global scope global-scope addresses to subnets
          connecting to other nodes, it would be necessary for every node to have
          an amount of prefix address space in on the order of the maximum number of
          subnets that the node could connect to to, and then the node would have to negotiate
          with adjacent nodes across those subnets whose which address space to use for each subnet.</li>
              <li>Using global scope
              <li pn="section-6.13.5.1-8.8" derivedCounter="8.">Using global-scope addresses for subnets between nodes is
          unnecessary if those subnets only connect routers, such as ACP secure channels,
          because they can communicate to remote nodes via their global scope global-scope loopback addresses.
          Using global scope global-scope addresses for those extern external subnets is therefore wasteful
          for the address space and also unnecessarily increasing increases the size of the routing
          and forwarding tables, which which, especially for the ACP ACP, is highly undesirable because
          it should attempt to minimize the per-node overhead of the ACP VRF.</li>
              <li>For
              <li pn="section-6.13.5.1-8.9" derivedCounter="9.">For all these reasons, the ACP addressing schemes sub-schemes do not consider
          ACP addresses for subnets connecting ACP nodes.</li>
            </ol>
            <t>Note
            <t indent="0" pn="section-6.13.5.1-9">Note that "<xref target="RFC8402" format="title" sectionFormat="of" derivedContent="Segment Routing Architecture"/>" <xref target="RFC8402" format="default"/> format="default" sectionFormat="of" derivedContent="RFC8402"/> introduces the term Node-SID to refer
        to IGP prefix segments that identify a specific router, for example example, on a loopback interface.
        An ACP loopback address prefix may similarly be called an ACP Node Identifier.</t>
          </section>
          <section anchor="ACP-virtual-interfaces" numbered="true" toc="default">
            <name>ACP virtual interfaces</name>
            <t>Any toc="include" removeInRFC="false" pn="section-6.13.5.2">
            <name slugifiedName="name-acp-virtual-interfaces">ACP Virtual Interfaces</name>
            <t indent="0" pn="section-6.13.5.2-1">Any ACP secure channel to another ACP node is
        mapped to ACP virtual interfaces in one of the following ways.
        This is independent of the chosen secure channel protocol (IPsec, DTLS DTLS,
        or other future protocol - standards protocol, either standardized or non-standards).</t>
            <t>Note not).</t>
            <t indent="0" pn="section-6.13.5.2-2">Note that all the considerations described here are assuming assume point-to-point
        secure channel associations. Mapping multi-party multiparty secure channel associations associations, such as
        "<xref target="RFC6407" format="title" sectionFormat="of" derivedContent="The Group Domain of Interpretation"/>" <xref target="RFC6407" format="default"/> format="default" sectionFormat="of" derivedContent="RFC6407"/>, is out of scope.</t>
            <section anchor="ACP-p2p-virtual-interfaces" numbered="true" toc="default">
              <name>ACP point-to-point virtual interfaces</name>
              <t>In toc="include" removeInRFC="false" pn="section-6.13.5.2.1">
              <name slugifiedName="name-acp-point-to-point-virtual-">ACP Point-to-Point Virtual Interfaces</name>
              <t indent="0" pn="section-6.13.5.2.1-1">In this option, each ACP secure channel is
        mapped into to a separate point-to-point ACP virtual interface.  If a
        physical subnet has more than two ACP capable ACP-capable nodes (in the same domain),
        this implementation approach will lead to a full mesh of ACP virtual
        interfaces between them.</t>
              <t>When
              <t indent="0" pn="section-6.13.5.2.1-2">When the secure channel protocol determines a peer to be dead, this SHOULD <bcp14>SHOULD</bcp14>
        result in indicating link breakage to trigger RPL DODAG repair, see
        <xref target="rpl-dodag-repair" format="default"/>.</t> format="default" sectionFormat="of" derivedContent="Section 6.12.1.7"/>.</t>
            </section>
            <section anchor="ACP-ma-virtual-interfaces" numbered="true" toc="default">
              <name>ACP multi-access virtual interfaces</name>
              <t>In toc="include" removeInRFC="false" pn="section-6.13.5.2.2">
              <name slugifiedName="name-acp-multi-access-virtual-in">ACP Multi-Access Virtual Interfaces</name>
              <t indent="0" pn="section-6.13.5.2.2-1">In a more advanced implementation approach,
        the ACP will construct a single multi-access ACP virtual interface for
        all ACP secure channels to ACP capable ACP-capable nodes reachable across the same
        underlying (physical) subnet.  IPv6 link-local multicast packets
        sent into to an ACP multi-access virtual interface are replicated to
        every ACP secure channel mapped into to the ACP multicast-access multi-access virtual
        interface.  IPv6 unicast packets sent into to an ACP multi-access virtual
        interface are sent to the ACP secure channel that belongs to the
        ACP neighbor that is the next-hop next hop in the ACP forwarding table entry
        used to reach the packets packets' destination address.</t>
              <t>When
              <t indent="0" pn="section-6.13.5.2.2-2">When the secure channel protocol determines that a peer to be is dead for a
        secure channel mapped into to an ACP multi-access virtual interface,
        this SHOULD <bcp14>SHOULD</bcp14> result in signaling breakage of that peer to RPL, so it can trigger
        RPL DODAG repair, see <xref target="rpl-dodag-repair" format="default"/>.</t>
              <t>There format="default" sectionFormat="of" derivedContent="Section 6.12.1.7"/>.</t>
              <t indent="0" pn="section-6.13.5.2.2-3">There is no requirement for
        all ACP nodes on the same multi-access subnet to use the same
        type of ACP virtual interface.  This is purely a node local node-local
        decision.</t>
              <t>ACP
              <t indent="0" pn="section-6.13.5.2.2-4">ACP nodes MUST <bcp14>MUST</bcp14> perform standard IPv6 operations across ACP
        virtual interfaces including SLAAC (Stateless Address Auto-Configuration)
        -
        <xref target="RFC4862" format="default"/>) format="default" sectionFormat="of" derivedContent="RFC4862"/> to assign their IPv6 link local link-local address on the ACP
        virtual interface and ND (Neighbor ("<xref target="RFC4861" format="title" sectionFormat="of" derivedContent="Neighbor Discovery - for IP version 6 (IPv6)"/>" <xref target="RFC4861" format="default"/>) format="default" sectionFormat="of" derivedContent="RFC4861"/>)
        to discover which IPv6 link-local neighbor address belongs to
        which ACP secure channel mapped to the ACP virtual interface.
        This is independent of whether the ACP virtual interface is point-to-point or multi-access.</t>
              <t>"Optimistic
              <t indent="0" pn="section-6.13.5.2.2-5">Optimistic Duplicate Address Detection (DAD)" (DAD) according to
        "<xref target="RFC4429" format="title" sectionFormat="of" derivedContent="Optimistic Duplicate Address Detection (DAD) for IPv6"/>" <xref target="RFC4429" format="default"/> format="default" sectionFormat="of" derivedContent="RFC4429"/> is RECOMMENDED <bcp14>RECOMMENDED</bcp14> because the likelihood for
        duplicates between ACP nodes is highly improbable as long as
        the address can be formed from a globally unique local unique, locally assigned identifier
        (e.g., EUI-48/EUI-64, see below).</t>
              <t>ACP
              <t indent="0" pn="section-6.13.5.2.2-6">ACP nodes MAY <bcp14>MAY</bcp14> reduce the amount of link-local IPv6 multicast
        packets from ND by learning the IPv6 link-local neighbor address
        to ACP secure channel mapping from other messages messages, such as the source
        address of IPv6 link-local multicast RPL messages - messages, and therefore
        forego the need to send Neighbor Solicitation messages.</t>
              <t>The
              <t indent="0" pn="section-6.13.5.2.2-7">The ACP virtual interface IPv6 link local link-local address can be derived from
        any appropriate local mechanism mechanism, such as node local node-local EUI-48 or EUI-64
        ("EUI" stands for "Extended Unique Identifier"). EUI-64.
        It MUST NOT <bcp14>MUST NOT</bcp14> depend on something that is attackable from the Data-Plane data plane, such
        as the IPv6 link-local address of the underlying physical interface, which
        can be attacked by SLAAC, or parameters of the secure channel encapsulation header
        that may not be protected by the secure channel mechanism.</t>
              <t>The
              <t indent="0" pn="section-6.13.5.2.2-8">The link-layer address of an ACP virtual interface is the
        address used for the underlying interface across which the secure
        tunnels are built, typically Ethernet addresses.  Because unicast IPv6
        packets sent to an ACP virtual interface are not sent to a link-layer
        destination address but rather to an ACP secure channel,
        the link-layer address fields SHOULD <bcp14>SHOULD</bcp14> be ignored on reception reception, and
        instead the ACP secure channel from which the message was
        received should be remembered.</t>
              <t>Multi-access
              <t indent="0" pn="section-6.13.5.2.2-9">Multi-access ACP virtual interfaces are preferable implementations
        when the underlying interface is a (broadcast) multi-access subnet because they do
        reflect the presence of the underlying multi-access subnet into to the virtual
        interfaces of the ACP.  This makes it it, for example example, simpler to build services
        with topology awareness inside the ACP VRF in the same way as they could
        have been built running natively on the multi-access interfaces.</t>
              <t>Consider
              <t indent="0" pn="section-6.13.5.2.2-10">Consider also the impact of point-to-point vs. multi-access virtual interface interfaces
        on the efficiency of flooding via link local multicasted messages:</t>
              <t>Assume link-local multicast messages.</t>
              <t indent="0" pn="section-6.13.5.2.2-11">Assume a LAN with three ACP neighbors, Alice, Bob Bob, and Carol.
        Alice's ACP GRASP wants to send a link-local GRASP multicast message to
        Bob and Carol.  If Alice's ACP emulates the LAN as per-peer, point-to-point
        virtual interfaces, one to Bob and one to Carol, Alice's ACP GRASP will
        send two copies of multicast GRASP messages: One one to Bob and one to Carol.
        If Alice's ACP emulates a LAN via a multipoint virtual interface, Alice's ACP GRASP will send one packet
        to that interface interface, and the ACP multipoint virtual interface will replicate the packet to each secure channel,
        one to Bob, one to Carol.  The result is the same.  The difference
        happens when Bob and Carol receive their packet. packets.  If they use ACP point-to-point
        virtual interfaces, their GRASP instance would forward the packet
        from Alice to each other as part of the GRASP flooding procedure.
        These packets are unnecessary and would be discarded by GRASP
        on receipt as duplicates (by use of the GRASP Session ID).
        If Bob and Carol's ACP would emulate emulated a multi-access
        virtual interface, then this would not happen, happen because GRASPs GRASP's flooding procedure
        does not replicate back packets back to the interface that from which they were received from.</t>
              <t>Note received.</t>
              <t indent="0" pn="section-6.13.5.2.2-12">Note that link-local GRASP multicast messages are not sent
        directly as IPv6 link-local multicast UDP messages into to ACP virtual interfaces,
        but instead into to ACP GRASP virtual interfaces, interfaces that are layered on top of
        ACP virtual interfaces to add TCP reliability to link-local multicast
        GRASP messages.  Nevertheless, these ACP GRASP virtual interfaces perform the
        same replication of message and, therefore, result in messages and therefore have the same impact on flooding.
        See <xref target="GRASP-substrate" format="default"/> format="default" sectionFormat="of" derivedContent="Section 6.9.2"/> for more details.</t>
              <t>RPL
              <t indent="0" pn="section-6.13.5.2.2-13">RPL does support operations and correct routing table construction
        across non-broadcast multi-access (NBMA) subnets.  This is common when using many
        radio technologies.  When such NBMA subnets are used, they MUST NOT <bcp14>MUST NOT</bcp14> be
        represented as ACP multi-access virtual interfaces because the replication
        of IPv6 link-local multicast messages will not reach all
        NBMA subnet neighbors.  In  As a result, GRASP message flooding would fail.
        Instead, each ACP secure channel across such an interface MUST <bcp14>MUST</bcp14> be
        represented as a an ACP point-to-point virtual interface. See also <xref target="future-rpl" format="default"/>.</t>
              <t>Care format="default" sectionFormat="of" derivedContent="Appendix A.9.4"/>.</t>
              <t indent="0" pn="section-6.13.5.2.2-14">Care needs to be taken when creating multi-access ACP virtual
        interfaces across ACP secure channels between ACP nodes in different domains
        or routing subdomains. If If, for example example, future inter-domain ACP policies
        are defined as "peer-to-peer" policies, it is easier to create ACP point-to-point
        virtual interfaces for these inter-domain secure channels.</t>
            </section>
          </section>
        </section>
        <!-- acp_interfaces -->
      </section>
      <!-- acp_general -->
    </section>

    <!-- self-creation -->
      </section>
    </section>
    <section anchor="acp-l2-switches" numbered="true" toc="default">
      <name>ACP support toc="include" removeInRFC="false" pn="section-7">
      <name slugifiedName="name-acp-support-on-l2-switches-">ACP Support on L2 switches/ports Switches/Ports (Normative)</name>
      <section anchor="acp-l2-switches-why" numbered="true" toc="default">
        <name>Why toc="include" removeInRFC="false" pn="section-7.1">
        <name slugifiedName="name-why-benefits-of-acp-on-l2-s">Why (Benefits of ACP on L2 switches)</name> Switches)</name>
        <figure anchor="acp-example">
          <name>Topology anchor="acp-example" align="left" suppress-title="false" pn="figure-13">
          <name slugifiedName="name-topology-with-l2-acp-switch">Topology with L2 ACP switches</name> Switches</name>
          <artwork name="" type="" align="left" alt=""><![CDATA[ alt="" pn="section-7.1-1.1">
    ANrtr1 ------ ANswitch1 --- ANswitch2 ------- ANrtr2
              .../   \                   \  ...
    ANrtrM ------     \                   ------- ANrtrN
                       ANswitchM ...
        ]]></artwork>
</artwork>
        </figure>
        <t>Consider
        <t indent="0" pn="section-7.1-2">Consider a large L2 LAN with ANrtr1...ANrtrN routers ANrtr1 through ANrtrN connected via some topology of L2 switches.
Examples include large enterprise campus networks with an L2 core, IoT networks networks, or broadband
aggregation networks networks, which often have even a multi-level L2 switched multilevel L2-switched topology.</t>
        <t>If
        <t indent="0" pn="section-7.1-3">If the discovery protocol used for the ACP is operating operates at the subnet level, every ACP router
will see all other ACP routers on the LAN as neighbors neighbors, and a full mesh of ACP channels will be built.
If some or all of the AN switches are autonomic with the same discovery protocol, then the
full mesh would include those switches as well.</t>
        <t>A
        <t indent="0" pn="section-7.1-4">A full mesh of ACP connections can create fundamental scale challenges.  The number of
security associations of the secure channel protocols will likely not scale arbitrarily,
especially when they leverage platform accelerated platform-accelerated encryption/decryption.  Likewise, any
other ACP operations (such as routing) needs need to scale to the number of direct ACP neighbors.  An
ACP router with just 4 four physical interfaces might be deployed into a LAN with hundreds of neighbors connected
via switches.  Introducing such a new new, unpredictable scaling factor requirement makes it harder
to support the ACP on arbitrary platforms and in arbitrary deployments.</t>
        <t>Predictable
        <t indent="0" pn="section-7.1-5">Predictable scaling requirements for ACP neighbors can most easily be achieved if if, in
topologies such as these, ACP capable ACP-capable L2 switches can ensure that discovery messages terminate
on them so that neighboring ACP routers and switches will only find the physically connected
ACP L2 switches as their candidate ACP neighbors.  With such a discovery mechanism in place, the
ACP and its security associations will only need to scale to the number of physical interfaces
instead of a potentially much larger number of "LAN-connected" neighbors.  And neighbors, and the ACP topology
will follow directly the physical topology, something which that can then also be leveraged
in management operations or by ASAs.</t>
        <t>In
        <t indent="0" pn="section-7.1-6">In the example above, consider that ANswitch1 and ANswitchM are ACP capable, and ANswitch2
is not ACP capable.  The desired ACP topology is that ANrtr1 and ANrtrM only have an
ACP connection to ANswitch1, and that ANswitch1, ANrtr2, and ANrtrN have a full mesh of ACP
connection
connections amongst each other.  ANswitch1 also has an ACP connection with ANswitchM ANswitchM, and
ANswitchM has ACP connections to anything else behind it.</t>
      </section>
      <!-- switched-lans-why -->
      <section anchor="acp-l2-switches-how" numbered="true" toc="default">
        <name>How toc="include" removeInRFC="false" pn="section-7.2">
        <name slugifiedName="name-how-per-l2-port-dull-grasp">How (per L2 port Port DULL GRASP)</name>
        <t>To
        <t indent="0" pn="section-7.2-1">To support ACP on L2 switches or L2 switched L2-switched ports of an L3 device, it is necessary to
make those L2 ports look like L3 interfaces for the ACP implementation.  This primarily involves
the creation of a separate DULL GRASP instance/domain on every such L2 port.  Because GRASP
has a dedicated link-local IPv6 multicast address (ALL_GRASP_NEIGHBORS), it is sufficient that all packets
for this address are being extracted at the port level and passed to that DULL GRASP instance.
Likewise
Likewise, the IPv6 link-local multicast packets sent by that DULL GRASP instance need to be
sent only towards the L2 port for this DULL GRASP instance (instead of being flooded across
all ports of the VLAN to which the port belongs).</t>
        <t>When Ports/Interfaces
        <t indent="0" pn="section-7.2-2">When the ports/interfaces across which the ACP is expected to operate in an ACP-aware L2-switch L2 switch or L2/L3-switch/router L2/L3 switch/router are L2-bridged, packets for the ALL_GRASP_NEIGHBORS multicast address MUST <bcp14>MUST</bcp14> never be forward forwarded between these ports. If MLD snooping is used, it MUST <bcp14>MUST</bcp14> be prohibited from bridging packets for the ALL_GRASP_NEIGHBORS IPv6 multicast address.</t>
        <t>On
        <t indent="0" pn="section-7.2-3">On hybrid L2/L3 switches, multiple L2 ports are assigned to a single L3
VLAN interface. With the aforementioned changes for DULL GRASP, ACP can
simply operate on the L3 VLAN interfaces, so no further (hardware) forwarding
changes are required to make ACP operate on L2 ports. This is possible because
the ACP secure channel protocols only use link-local IPv6 unicast packets,
and these packets will be sent to the correct L2 port towards the
peer by the VLAN logic of the device.</t>
        <t>This
        <t indent="0" pn="section-7.2-4">This is sufficient when p2p P2P ACP virtual interfaces are established to
every ACP peer. When it is desired to create multi-access ACP virtual interfaces
(see <xref target="ACP-ma-virtual-interfaces" format="default"/>), format="default" sectionFormat="of" derivedContent="Section 6.13.5.2.2"/>), it is REQIURED <bcp14>REQUIRED</bcp14> not to coalesce all
 the ACP secure channels on the same L3 VLAN interface, but only all those on the same L2 port.</t>
        <t>If
        <t indent="0" pn="section-7.2-5">If VLAN tagging is used, then all the above described logic described above only applies to
untagged GRASP packets. For the purpose of ACP neighbor discovery via GRASP,
no VLAN tagged VLAN-tagged packets SHOULD <bcp14>SHOULD</bcp14> be sent or received. In a hybrid L2/L3
switch, each VLAN would therefore only create ACP adjacencies across those
ports where the VLAN is carried untagged.</t>
        <t>In
        <t indent="0" pn="section-7.2-6">As a result, the simple logic is that ACP secure channels would operate
over the same L3 interfaces that present a single single, flat bridged network
across all routers, but because DULL GRASP is separated on a per-port basis,
no full mesh of ACP secure channels is created, but only per-port ACP
secure channels to per-port L2-adjacent ACP node neighbors.</t>
        <t>For
        <t indent="0" pn="section-7.2-7">For example, in the above picture, ANswitch1 would run separate DULL GRASP instances on its ports
to ANrtr1, ANswitch2 ANswitch2, and ANswitchI, even though all those three ports may be in the data plane
in the same (V)LAN and perform L2 switching between these ports, ANswitch1 would perform
ACP L3 routing between them.</t>
        <t>The
        <t indent="0" pn="section-7.2-8">The description in the previous paragraph was is specifically meant to illustrate that that, on hybrid
L3/L2 devices that are common in enterprise, IoT IoT, and broadband aggregation, there is only
the GRASP packet extraction (by Ethernet address) and GRASP link-local multicast per
L2-port packet injection that has to consider L2 ports at the hardware forwarding hardware-forwarding level.
The remaining operations are purely ACP control plane and setup of secure channels across the
L3 interface.  This hopefully makes support for per-L2 port ACP on those hybrid devices easy.</t>
        <t>In
        <t indent="0" pn="section-7.2-9">In devices without such a mix of L2 port/interfaces and L3 interfaces (to terminate any
transport layer
transport-layer connections), implementation details will differ.  Logically and most simply every
L2 port is considered and used as a separate L3 subnet for all ACP operations.  The fact that
the ACP only requires IPv6 link-local unicast and multicast should make support for it on any
type of L2 devices as simple as possible.</t>
        <t>A
        <t indent="0" pn="section-7.2-10">A generic issue with ACP in L2 switched L2-switched networks is the interaction with the Spanning Tree
Protocol.
Protocol (STP).  Without further L2 enhancements, the ACP would run only across the active STP
topology
topology, and the ACP would be interrupted and re-converge reconverge with STP changes.
Ideally, ACP peering SHOULD <bcp14>SHOULD</bcp14> be built also across ports that are blocked in STP so
that the ACP does not depend on STP and can continue to run unaffected across STP topology
changes, where re-convergence reconvergence can be quite slow.  The above described simple implementation
options are not sufficient to achieve this.</t>
      </section>
      <!-- switched-lans-how -->
    </section>
    <!-- switched-lans -->
    </section>
    <section anchor="workarounds" numbered="true" toc="default">
      <name>Support toc="include" removeInRFC="false" pn="section-8">
      <name slugifiedName="name-support-for-non-acp-compone">Support for Non-ACP Components (Normative)</name>
      <section anchor="ACPconnect" numbered="true" toc="default">
        <name>ACP toc="include" removeInRFC="false" pn="section-8.1">
        <name slugifiedName="name-acp-connect">ACP Connect</name>
        <section anchor="NMS" numbered="true" toc="default">
          <name>Non-ACP toc="include" removeInRFC="false" pn="section-8.1.1">
          <name slugifiedName="name-non-acp-controller-and-or-n">Non-ACP Controller / NMS system</name>
          <t>The Autonomic Control Plane and/or Network Management System (NMS)</name>
          <t indent="0" pn="section-8.1.1-1">The ACP can be used by management systems, such as controllers or network management system (NMS) hosts (henceforth called simply "NMS hosts"), NMS hosts, to connect to devices (or other type of nodes) through it.  For this, an NMS host needs to have access to the ACP.  The ACP is a self-protecting overlay network, which allows by default access only to trusted, autonomic systems. systems by default.  Therefore, a traditional, non-ACP NMS system does not have access to the ACP by default, such as any other external node.</t>
          <t>If
          <t indent="0" pn="section-8.1.1-2">If the NMS host is not autonomic, i.e., it does not support autonomic negotiation of the ACP, then it can be brought into the ACP by explicit configuration.  To support connections to adjacent non-ACP nodes, an ACP node SHOULD <bcp14>SHOULD</bcp14> support "ACP connect" (sometimes also called "autonomic connect"):</t>
          <t>"ACP connect").</t>
          <t indent="0" pn="section-8.1.1-3">"ACP connect" is an interface level interface-level, configured workaround for connection of trusted non-ACP nodes to the ACP. The ACP node on which ACP connect is configured is called an "ACP edge node". With ACP connect, the ACP is accessible from those non-ACP nodes (such as NOC systems) on such an interface without those non-ACP nodes having to support any ACP discovery or ACP channel setup.  This is also called "native" access to the ACP because because, to those NOC systems systems, the interface looks like a normal network interface without any ACP secure channel that is encapsulating the traffic.</t>
          <figure anchor="acp-connect">
            <name>ACP connect</name> anchor="acp-connect" align="left" suppress-title="false" pn="figure-14">
            <name slugifiedName="name-acp-connect-2">ACP Connect</name>
            <artwork name="" type="" align="left" alt=""><![CDATA[

                                 Data-Plane alt="" pn="section-8.1.1-4.1">

                                 Data Plane "native" (no ACP)
                                          .
+--------+       +----------------+       .        +-------------+
| ACP    |       |ACP Edge Node   |       .        |             |
| Node   |       |                |       v        |             |
|        |-------|...[ACP VRF]....+----------------|             |+
|        |   ^   |.               |                | NOC Device  ||
|        |   .   | .[Data-Plane]..+----------------| .[Data Plane]..+----------------| "NMS hosts" ||
|        |   .   |  [          ]  | .         ^    |             ||
+--------+   .   +----------------+  .        .    +-------------+|
             .                        .       .     +-------------+
             .                        .       .
          Data-Plane
          Data Plane "native"         .   ACP "native" (unencrypted)
        + ACP auto-negotiated         .   "ACP connect subnet"
          and encrypted               .
                                    ACP connect interface
                                    e.g., "VRF ACP native" (config)

                                ]]></artwork>

</artwork>
          </figure>
          <t>ACP
          <t indent="0" pn="section-8.1.1-5">ACP connect has security consequences: All all systems and processes connected via ACP connect have access to all ACP nodes on the entire ACP, without further authentication.  Thus, the ACP connect interface and the NOC systems connected to it needs need to be physically controlled/secured. controlled and/or secured.  For this reason reason, the mechanisms described here do explicitly do not include options to allow for a non-ACP router to be connected across an ACP connect interface and addresses behind such a router routed inside the ACP.</t>
          <t>Physical controlled/secured
          <t indent="0" pn="section-8.1.1-6">Physically controlled and/or secured means that attackers can cannot gain no access to the physical device hosting the ACP Edge Node, edge node, the physical interfaces and links providing the ACP connect link link, nor the physical devices hosting the NOC Device. device. In a simple case, ACP Edge edge node and NOC Device device are co-located colocated in an access controlled access-controlled room, such as a NOC, to which attackers cannot gain physical access.</t>
          <t>An
          <t indent="0" pn="section-8.1.1-7">An ACP connect interface provides exclusively exclusive access to only the ACP.  This is likely insufficient for many NMS hosts.  Instead, they would require a second "Data-Plane" "data plane" interface outside the ACP for connections between the NMS host and administrators, or Internet based Internet-based services, or for direct access to the Data-Plane. data plane.  The document <xref target="RFC8368" format="default">"Using format="default" sectionFormat="of" derivedContent="RFC8368">"Using Autonomic Control Plane for Stable Connectivity of Network OAM"</xref> explains in more detail how the ACP can be integrated in a mixed NOC environment.</t>
          <t>An
          <t indent="0" pn="section-8.1.1-8">An ACP connect interface SHOULD <bcp14>SHOULD</bcp14> use an IPv6 address/prefix
from the ACP Manual Addressing Sub-Scheme (<xref target="manual-scheme" format="default"/>), format="default" sectionFormat="of" derivedContent="Section 6.11.4"/>), letting the operator configure configure, for example example, only the Subnet-ID and having the node automatically assign the remaining part of the prefix/address.  It SHOULD NOT <bcp14>SHOULD NOT</bcp14> use a prefix that is also routed outside the ACP so that the addresses clearly indicate whether it is used inside the ACP or not.</t>
          <t>The
          <t indent="0" pn="section-8.1.1-9">The prefix of ACP connect subnets MUST <bcp14>MUST</bcp14> be
	  distributed by the ACP edge node into the ACP routing protocol protocol, RPL.
	  The NMS hosts MUST host <bcp14>MUST</bcp14> connect to prefixes in the ACP
	  routing table via its ACP connect interface.  In the simple case
	  where the ACP uses only one ULA prefix prefix, and all ACP connect subnets
	  have prefixes covered by that ULA prefix, NMS hosts can rely on
	  <xref target="RFC6724" format="default"/> format="default" sectionFormat="of" derivedContent="RFC6724"/> to determine longest match
	  prefix routes towards its different interfaces, ACP and Data-Plane.
	  data plane. With RFC6724, The <xref target="RFC6724" format="default" sectionFormat="of" derivedContent="RFC6724"/>, the NMS host will select the ACP connect interface for all addresses in the ACP because any ACP destination address is longest matched by the address on the ACP connect interface.  If the NMS hosts host's ACP connect interface uses another prefix prefix, or if the ACP uses multiple ULA prefixes, then the NMS hosts require host requires (static) routes towards the ACP interface for these prefixes.</t>
          <t>
          <t indent="0" pn="section-8.1.1-10"> When an ACP Edge edge node receives a packet from an ACP connect interface, the ACP Edge edge node
MUST
<bcp14>MUST</bcp14> only forward the packet into to the ACP if the packet has an IPv6 source address from that interface (this is sometimes called "RPF filtering"). Reverse Path Forwarding (RPF) filtering).  This filtering rule MAY <bcp14>MAY</bcp14> be changed through administrative measures. The more any such administrative action enable enables reachability of non ACP non-ACP nodes to the ACP, the more this may cause security issues.</t>
          <t>To
          <t indent="0" pn="section-8.1.1-11">To limit the security impact of ACP connect, nodes supporting it SHOULD <bcp14>SHOULD</bcp14> implement a security
mechanism to allow configuration/use configuration and/or use of ACP connect interfaces only on nodes explicitly targeted
to be deployed with it (those in physically secure locations such as a NOC).  For example,
the registrar could disable the ability to enable ACP connect on devices during enrollment enrollment,
and that property could only be changed through re-enrollment. reenrollment.  See also <xref target="role-assignments" format="default"/>.</t>
          <t>ACP Edge format="default" sectionFormat="of" derivedContent="Appendix A.9.5"/>.</t>
          <t indent="0" pn="section-8.1.1-12">ACP edge nodes SHOULD <bcp14>SHOULD</bcp14> have a configurable option to prohibit packets with RPI headers (see <xref target="rpl-Data-Plane" format="default"/> format="default" sectionFormat="of" derivedContent="Section 6.12.1.13"/>) across an ACP connect interface. These headers are outside the scope of the RPL profile in this specification but may be used in future extensions of this specification.</t>
        </section>
        <!-- NMS -->
        <section anchor="software" numbered="true" toc="default">
          <name>Software toc="include" removeInRFC="false" pn="section-8.1.2">
          <name slugifiedName="name-software-components">Software Components</name>
          <t>The
          <t indent="0" pn="section-8.1.2-1">The previous section assumed that the ACP Edge edge node and NOC devices are separate physical devices and that the ACP connect interface is a physical network connection. This section discusses the implication when these components are instead software components running on a single physical device.</t>
          <t>The
          <t indent="0" pn="section-8.1.2-2">The ACP connect mechanism cannot only can be used not only to connect physically external systems (NMS hosts) to the ACP but also other applications, containers containers, or virtual machines.  In fact, one possible way to eliminate the security issue of the external ACP connect interface is to collocate colocate an ACP edge node and an NMS host by making one a virtual machine or container inside the other; and therefore converting the unprotected external ACP subnet into an internal virtual subnet in a single device.  This would ultimately result in a fully ACP enabled ACP-enabled NMS host with minimum impact to the NMS hosts host's software architecture.  This approach is not limited to NMS hosts but could equally be applied to devices consisting of one or more VNF (virtual network functions): An an internal virtual subnet connecting out-of-band management interfaces of the VNFs to an ACP edge router VNF.</t>
          <t>The
          <t indent="0" pn="section-8.1.2-3">The core requirement is that the software components need to have a network stack that permits access to the ACP and optionally also to the Data-Plane. data plane.  Like in the physical setup for NMS hosts hosts, this can be realized via two internal virtual subnets.  One subnets: one that is connecting connects to the ACP (which could be a container or virtual machine by itself), and one (or more) connecting into to the Data-Plane.</t>
          <t>This data plane.</t>
          <t indent="0" pn="section-8.1.2-4">This "internal" use of the ACP connect approach should not be considered to be a "workaround" because because, in this case case, it is possible to build a correct security model: It it is not necessary to rely on unprovable unprovable, external physical security mechanisms as in the case of external NMS hosts.  Instead, the orchestration of the ACP, the virtual subnets subnets, and the software components can be done by trusted software that could be considered to be part of the ANI (or even an extended ACP).  This software component is responsible for ensuring that only trusted software components will get access to that virtual subnet and that only even more trusted software components will get access to both the ACP virtual subnet and the Data-Plane data plane (because those ACP users could leak traffic between ACP and Data-Plane). data plane).  This trust could be established established, for example example, through cryptographic means such as signed software packages.</t>
        </section>
        <!-- software -->
        <section anchor="ACautoconfig" numbered="true" toc="default">
          <name>Auto Configuration</name>
          <t>ACP toc="include" removeInRFC="false" pn="section-8.1.3">
          <name slugifiedName="name-autoconfiguration">Autoconfiguration</name>
          <t indent="0" pn="section-8.1.3-1">ACP edge nodes, NMS hosts hosts, and software components that that, as described in the previous section section, are meant to be composed via virtual interfaces SHOULD <bcp14>SHOULD</bcp14> support SLAAC <xref target="RFC4862" format="default" sectionFormat="of" derivedContent="RFC4862"/> on the ACP connect subnet StateLess Address Autoconfiguration (SLAAC - <xref target="RFC4862" format="default"/>) and route auto configuration autoconfiguration according to <xref "<xref target="RFC4191" format="default"/>.</t>

          <t>The format="title" sectionFormat="of" derivedContent="Default Router Preferences and More-Specific Routes"/>" <xref target="RFC4191" format="default" sectionFormat="of" derivedContent="RFC4191"/>.</t>
          <t indent="0" pn="section-8.1.3-2">The ACP edge node acts as the router towards the ACP on the ACP connect subnet,
          providing the (auto-)configured (auto)configured prefix for the ACP connect subnet and
          (auto-)configured
          (auto)configured routes into to the ACP to NMS hosts and/or software components.</t>

          <t>
          <t indent="0" pn="section-8.1.3-3"> The ACP edge node uses the Route Information Option (RIO) of RFC4191 <xref target="RFC4191" format="default" sectionFormat="of" derivedContent="RFC4191"/> to announce
          aggregated prefixes for address prefixes used in the ACP (with normal RIO lifetimes. lifetimes).
          In addition, the ACP edge node also uses a RIO to announce the default route (::/0) with
          a lifetime of 0.</t>

          <t>These
          <t indent="0" pn="section-8.1.3-4">These RIOs allow to connect Type the connecting of type C hosts to the ACP via an ACP connect subnet on one interface
          and another network (Data Plane / and/or NMS network) on the same or another interface of the Type type C host, relying on other
          routers other than the ACP edge node. The RIOs ensure that these hosts will only route the prefixes used in the ACP to
          the ACP edge node.</t>
          <t>Type A/B host
          <t indent="0" pn="section-8.1.3-5">Type A and B hosts ignore the RIOs and will consider the ACP node to be their default router for
          all destination. destinations.  This is sufficient when the type A/B hosts A or type B host only need needs to connect to the ACP but not to other networks.
          Attaching Type A/B hosts a type A or type B host to both the ACP and other networks, networks
   requires either explicit ACP prefix route configuration on either the Type A/B hosts host or
   the combined ACP/Data-Plane ACP and data plane interface on the ACP edge node,
          see <xref target="SingleIF" format="default"/>.</t>

          <t>Aggregated format="default" sectionFormat="of" derivedContent="Section 8.1.4"/>.</t>
          <t indent="0" pn="section-8.1.3-6">Aggregated prefix means that the ACP edge node needs to only announce
          the /48 ULA prefixes used in the ACP but none of the actual /64
           (Manual Addressing Sub-Scheme), /127 (ACP Zone (Zone Addressing Sub-Scheme),
           /112 or /120 (Vlong Addressing Sub-Scheme) routes of actual ACP nodes.
           If ACP interfaces are configured with non ULA non-ULA prefixes, then those prefixes cannot be aggregated without further configured policy on the ACP edge node.  This explains the above recommendation to use ACP ULA prefix covered prefixes for ACP connect interfaces: They they allow for a shorter list of prefixes to be signaled via RFC4191 <xref target="RFC4191" format="default" sectionFormat="of" derivedContent="RFC4191"/> to NMS hosts and software components.</t>

          <t>The
          <t indent="0" pn="section-8.1.3-7">The ACP edge nodes that have a Vlong ACP address MAY <bcp14>MAY</bcp14> allocate a subset of their /112 or /120 address prefix to ACP connect interface(s) to eliminate the need to non-autonomically configure/provision configure and/or provision the address prefixes for such ACP connect interfaces.</t>
          <!--  See <xref target="up4291"/> for considerations how this updates the IPv6 address architecture and ULA specification.</t> -->
        </section>
        <!-- ACautoconfig -->
        <section anchor="SingleIF" numbered="true" toc="default">
          <name>Combined ACP/Data-Plane toc="include" removeInRFC="false" pn="section-8.1.4">
          <name slugifiedName="name-combined-acp-and-data-plane">Combined ACP and Data Plane Interface (VRF Select)</name>
          <figure anchor="vrf-select">
            <name>VRF select</name> anchor="vrf-select" align="left" suppress-title="false" pn="figure-15">
            <name slugifiedName="name-vrf-select">VRF Select</name>
            <artwork name="" type="" align="left" alt=""><![CDATA[ alt="" pn="section-8.1.4-1.1">

                     Combined ACP and Data-Plane data plane interface
                                             .
  +--------+       +--------------------+    .   +--------------+
  | ACP    |       |ACP Edge No         |    .   | NMS Host(s)  |
  | Node   |       |                    |    .   | / Software   |
  |        |       |  [ACP  ].          |    .   |              |+
  |        |       | .[VRF  ] .[VRF   ] |    v   | "ACP address"|| Address"||
  |        +-------+.         .[Select].+--------+ "Date "Data Plane  ||
  |        |   ^   | .[Data ].          |        |  Address(es)"||
  |        |   .   |  [Plane]           |        |              ||
  |        |   .   |  [     ]           |        +--------------+|
  +--------+   .   +--------------------+         +--------------+
               .
        Data-Plane
        Data plane "native" and + ACP auto-negotiated/encrypted

                                ]]></artwork>

</artwork>
          </figure>
          <t>Using
          <t indent="0" pn="section-8.1.4-2">Using two physical and/or virtual subnets (and therefore interfaces) into to NMS Hosts hosts (as per <xref target="NMS" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 8.1.1"/>) or Software software (as per <xref target="software" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 8.1.2"/>) may be seen as additional complexity, for example example, with legacy NMS Hosts hosts that support only one IP interface, or it may be insufficient to support <xref target="RFC4191" format="default"/> Type type A or type B host hosts <xref target="RFC4191" format="default" sectionFormat="of" derivedContent="RFC4191"/> (see <xref target="ACautoconfig" format="default"/>).</t>
          <t>To format="default" sectionFormat="of" derivedContent="Section 8.1.3"/>).</t>
          <t indent="0" pn="section-8.1.4-3">To provide a single subnet into to both the ACP and Data-Plane, Data plane, the ACP Edge edge node needs to de-multiplex demultiplex packets from NMS hosts into ACP VRF and Data-Plane. data plane.  This is sometimes called "VRF select".  If the ACP VRF has no overlapping IPv6 addresses with the Data-Plane data plane (it should have no overlapping addresses), then this function can use the IPv6 Destination destination address.  The problem is Source Address Selection source address selection on the NMS Host(s) host(s) according to RFC6724.</t>
          <t>Consider <xref target="RFC6724" format="default" sectionFormat="of" derivedContent="RFC6724"/>.</t>
          <t indent="0" pn="section-8.1.4-4">Consider the simple case: The the ACP uses only one ULA prefix, and the ACP IPv6 prefix for the Combined combined ACP and Data-Plane data plane interface is covered by that ULA prefix.  The ACP edge node announces both the ACP IPv6 prefix and one (or more) prefixes for the Data-Plane. data plane.  Without further policy configurations on the NMS Host(s), host(s), it may select its ACP address as a source address for Data-Plane data plane ULA destinations because of Rule 8 of RFC6724. (<xref target="RFC6724" section="5" sectionFormat="of" format="default" derivedLink="https://rfc-editor.org/rfc/rfc6724#section-5" derivedContent="RFC6724"/>).  The ACP edge node can pass on the packet to the Data-Plane, data plane, but the ACP source address should not be used for Data-Plane data plane traffic, and return traffic may fail.</t>
          <t>If
          <t indent="0" pn="section-8.1.4-5">If the ACP carries multiple ULA prefixes or non-ULA ACP connect prefixes, then the correct source address selection becomes even more problematic.</t>
          <t>With
          <t indent="0" pn="section-8.1.4-6">With separate ACP connect and Data-Plane data plane subnets and RFC4191 prefix announcements <xref target="RFC4191" format="default" sectionFormat="of" derivedContent="RFC4191"/> that are to be routed across the ACP connect interface, RFC6724 the source address selection of Rule 5 (use address of outgoing interface) (<xref target="RFC6724" section="5" sectionFormat="of" format="default" derivedLink="https://rfc-editor.org/rfc/rfc6724#section-5" derivedContent="RFC6724"/>) will be used, so that above problems do not occur, even in more complex cases of multiple ULA and non-ULA prefixes in the ACP routing table.</t>
          <t>To
          <t indent="0" pn="section-8.1.4-7">To achieve the same behavior with a Combined combined ACP and Data-Plane data plane interface, the ACP Edge Node edge node needs to behave as two separate routers on the interface: One one link-local IPv6 address/router for its ACP reachability, and one link-local IPv6 address/router for its Data-Plane data plane reachability.  The Router Advertisements for both are as described above (<xref in <xref target="ACautoconfig" format="default"/>): For format="default" sectionFormat="of" derivedContent="Section 8.1.3"/>: for the ACP, the ACP prefix is announced together with RFC4191 option for the prefixes prefix option <xref target="RFC4191" format="default" sectionFormat="of" derivedContent="RFC4191"/> routed across the ACP ACP, and lifetime=0 the lifetime is set to zero to disqualify this next-hop next hop as a default router.  For the Data-Plane, data plane, the Data-Plane data plane prefix(es) are announced together with whatever dafault default router parameters are used for the Data-Plane.</t>
          <t>In data plane.</t>
          <t indent="0" pn="section-8.1.4-8">As a result, RFC6724 source address selection Rule 5.5 (<xref target="RFC6724" section="5" sectionFormat="of" format="default" derivedLink="https://rfc-editor.org/rfc/rfc6724#section-5" derivedContent="RFC6724"/>) may result in the same correct source address selection behavior of NMS hosts without further configuration on it as the separate ACP connect and Data-Plane interfaces. data plane interfaces on the host.  As described in the text for Rule 5.5, 5.5 (<xref target="RFC6724" section="5" sectionFormat="of" format="default" derivedLink="https://rfc-editor.org/rfc/rfc6724#section-5" derivedContent="RFC6724"/>), this is only a MAY, <bcp14>MAY</bcp14> because IPv6 hosts are not required to track next-hop information.  If an NMS Host host does not do this, then separate ACP connect and Data-Plane data plane interfaces are the preferable method of attachment.  Hosts implementing "<xref target="RFC8028" format="title" sectionFormat="of" derivedContent="First-Hop Router Selection by Hosts in a Multi-Prefix Network"/>" <xref target="RFC8028" format="default"/> format="default" sectionFormat="of" derivedContent="RFC8028"/> should (instead of may) implement <xref target="RFC6724" format="default"/> Rule 5.5, 5.5 (<xref target="RFC6724" section="5" sectionFormat="of" format="default" derivedLink="https://rfc-editor.org/rfc/rfc6724#section-5" derivedContent="RFC6724"/>), so it is preferred for hosts to support <xref target="RFC8028" format="default"/>.</t>
          <t>ACP format="default" sectionFormat="of" derivedContent="RFC8028"/>.</t>
          <t indent="0" pn="section-8.1.4-9">ACP edge nodes MAY <bcp14>MAY</bcp14> support the Combined combined ACP and Data-Plane data plane interface.</t>
        </section>
        <!-- SingleIF -->
        <section anchor="ACgrasp" numbered="true" toc="default">
          <name>Use toc="include" removeInRFC="false" pn="section-8.1.5">
          <name slugifiedName="name-use-of-grasp">Use of GRASP</name>
          <t>GRASP
          <t indent="0" pn="section-8.1.5-1">GRASP can and should be possible to use across ACP connect interfaces, especially in
the architectural architecturally correct solution when it is used as a mechanism to connect Software software
(e.g., ASA or legacy NMS applications) to the ACP.</t>
          <t>Given
          <t indent="0" pn="section-8.1.5-2">Given how the ACP is the security and transport substrate for GRASP, the requirements
for
are that those devices connected via ACP connect is that those are equivalently (if not better)
secured against attacks than ACP nodes that do not use ACP connect connect, and they run only
software that is equally (if not better) protected, known (or trusted) not to be malicious malicious,
and accordingly designed to isolate access to the ACP against external equipment.</t>
          <t>The
          <t indent="0" pn="section-8.1.5-3">The difference in security is that cryptographic security of the
ACP secure channel is replaced by required physical security/control security and/or control of the network connection
between an ACP edge node and the NMS or other host reachable via the ACP connect
interface. See <xref target="NMS" format="default"/>.</t>
          <t>When format="default" sectionFormat="of" derivedContent="Section 8.1.1"/>.</t>
          <t indent="0" pn="section-8.1.5-4">When using "Combined the combined ACP and Data-Plane Interfaces", data plane interface, care has to be taken that
only GRASP messages received from software or
NMS hosts and intended for the ACP GRASP domain received from Software or
NMS Hosts are forwarded by ACP edge nodes.  Currently there is no definition for
a GRASP security and transport substrate beside the ACP, so there is no definition
how such Software/NMS Host software/NMS host could participate in two separate GRASP Domains domains across
the same subnet (ACP and Data-Plane data plane domains).  At current  Currently it is assumed that
all GRASP packets on a Combined combined ACP and Data-Plane data plane interface belong to the GRASP ACP Domain. domain.
They SHOULD <bcp14>SHOULD</bcp14> all use the ACP IPv6 addresses of the Software/NMS Hosts. software/NMS hosts.  The link-local
IPv6 addresses of Software/NMS Hosts software/NMS hosts (used for GRASP M_DISCOVERY and M_FLOOD messages)
are also assumed to belong to the ACP address space.</t>
        </section>
        <!-- ACgrasp -->
      </section>
      <!-- ACP connect -->
      <section anchor="remote-acp-neighbors" numbered="true" toc="default">
        <name>Connecting toc="include" removeInRFC="false" pn="section-8.2">
        <name slugifiedName="name-connecting-acp-islands-over">Connecting ACP islands Islands over Non-ACP L3 networks Networks (Remote ACP neighbors)</name>
        <t>Not Neighbors)</name>
        <t indent="0" pn="section-8.2-1">Not all nodes in a network may support the ACP.  If non-ACP Layer-2 L2 devices are between ACP nodes, the ACP will work across it them since it is IP based.  However, the autonomic discovery of ACP neighbors via DULL GRASP is only intended to work across L2 connections, so it is not sufficient to autonomically create ACP connections across non-ACP Layer-3 L3 devices.</t>
        <section anchor="conf-remote" numbered="true" toc="default">
          <name>Configured toc="include" removeInRFC="false" pn="section-8.2.1">
          <name slugifiedName="name-configured-remote-acp-neigh">Configured Remote ACP neighbor</name>
          <t>On Neighbor</name>
          <t indent="0" pn="section-8.2.1-1">On the ACP node, remote ACP neighbors are configured explicitly.
    The parameters of such a "connection" are described in the following ABNF.</t> ABNF.
    The syntax shown is non-normative (as there are no standards for
  configuration) but only meant to illustrate the parameters and which
  ones can be optional.</t>
          <figure anchor="abnf">
            <name>Parameters anchor="abnf" align="left" suppress-title="false" pn="figure-16">
            <name slugifiedName="name-parameters-for-remote-acp-n">Parameters for remote Remote ACP neighbors</name>
            <artwork Neighbors</name>
            <sourcecode name="" type="" align="left" alt=""><![CDATA[ type="abnf" markers="false" pn="section-8.2.1-2.1">
  connection = [ method , local-addr, remote-addr, ?pmtu "," local-addr "," remote-addr [ "," pmtu ]
  method =    "any"
             / ( "IKEv2" [ "IKEv2", ?port ":" port ]
  method =/ )
             / (  "DTLS"  [ "DTLS", ":"  port ] )
  port = 1*DIGIT
  local-addr  = [ address , ?vrf  [ ":" vrf  ] ]
  remote-addr = [   address ]
  address = ("any" | ipv4-address | ipv6-address )  "any"
             / IPv4address / IPv6address  ; From [RFC5954]
  vrf = tstr system-dependent ; Name of a VRF on this node with for local-address
 ]]></artwork>
</sourcecode>
          </figure>
          <t>Explicit
          <t indent="0" pn="section-8.2.1-3">Explicit configuration of a remote-peer remote peer according to this
ABNF provides all the information to build a secure channel without requiring a tunnel
to that peer and running DULL GRASP inside of it.</t>
          <t>The
          <t indent="0" pn="section-8.2.1-4">The configuration includes the parameters otherwise signaled
via DULL GRASP: local address, remote (peer) locator locator, and
method. The differences over DULL GRASP local neighbor
discovery and secure channel creation are as follows:</t>
          <ul spacing="compact">
            <li>The spacing="normal" bare="false" empty="false" indent="3" pn="section-8.2.1-5">
            <li pn="section-8.2.1-5.1">The local and remote address can be IPv4 or IPv6 and are typically global scope global-scope addresses.</li>
            <li>The
            <li pn="section-8.2.1-5.2">The VRF across which the connection is built (and in which local-addr exists) can to be specified.  If vrf is not specified, it is the default VRF on the node.  In DULL GRASP GRASP, the VRF is implied by the interface across which DULL GRASP operates.</li>
            <li>If
            <li pn="section-8.2.1-5.3">If local address is "any", the local address used when initiating a secure channel connection is decided by source address selection (<xref target="RFC6724" format="default"/> format="default" sectionFormat="of" derivedContent="RFC6724"/> for IPv6). As a responder, the connection listens on all addresses of the node in the selected VRF.</li>
            <li>Configuration
            <li pn="section-8.2.1-5.4">Configuration of port is only required for methods where no defaults exist (e.g., "DTLS").</li>
            <li>If
            <li pn="section-8.2.1-5.5">If the remote address is "any", the connection is only a responder. It is a "hub" that can be used by multiple remote peers to connect simultaneously - -- without having to know or configure their addresses. Example: Hub addresses, for example, a hub site for remote "spoke" sites reachable over the Internet.</li>
            <li>Pmtu
            <li pn="section-8.2.1-5.6">The pmtu parameter should be configurable to overcome issues/limitations issues or limitations of Path MTU Discovery (PMTUD).</li>
            <li>IKEv2/IPsec
            <li pn="section-8.2.1-5.7">IKEv2/IPsec to remote peers should support the optional NAT Traversal (NAT-T) procedures.</li>
          </ul>
        </section>
        <section anchor="conf-tunnel" numbered="true" toc="default">
          <name>Tunneled toc="include" removeInRFC="false" pn="section-8.2.2">
          <name slugifiedName="name-tunneled-remote-acp-neighbo">Tunneled Remote ACP Neighbor</name>

          <t>An IPinIP, GRE
          <t indent="0" pn="section-8.2.2-1">An IP-in-IP, GRE, or other form of pre-existing preexisting tunnel is configured
        between two remote ACP peers peers, and the virtual interfaces representing
        the tunnel are configured for "ACP enable".  This will enable IPv6
        link local
        link-local addresses and DULL on this tunnel.  In  As a result,  the tunnel
        is used for normal "L2 adjacent" candidate ACP neighbor discovery
        with DULL and secure channel setup procedures described in this document.</t>

          <t>Tunneled
          <t indent="0" pn="section-8.2.2-2">Tunneled Remote ACP Neighbor requires two encapsulations:
        the configured tunnel and the secure channel inside of that tunnel.
        This makes it in general less desirable than Configured Remote ACP Neighbor.
        Benefits of tunnels are that it may be easier to implement because
        there is no change to the ACP functionality - just running it over
        a virtual (tunnel) interface instead of only native interfaces.
        The tunnel itself may also provide PMTUD while the secure channel
        method may not.  Or the tunnel mechanism is permitted/possible through some
        firewall while the secure channel method may not.</t>

        <t>Tunneling
          <t indent="0" pn="section-8.2.2-3">Tunneling using an insecure tunnel encapsulation increases increases, on average average,
     the risk of a MITM downgrade attack somewhere along the underlay path
        that blocks path.
     In such an attack, the MITM filters packets for all but the most easily
     attacked ACP secure channel option to force use of that option.
        ACP nodes supporting tunneled remote Tunneled Remote ACP Neighbors SHOULD <bcp14>SHOULD</bcp14> support
        configuration on such tunnel interfaces to restrict or explicitly
        select the available ACP secure channel protocols
        (if the ACP node supports more than one ACP secure channel protocol in the first place).</t>
        </section>
        <section anchor="conf-summary" numbered="true" toc="default">
          <name>Summary</name>
          <t>Configured/Tunneled toc="include" removeInRFC="false" pn="section-8.2.3">
          <name slugifiedName="name-summary">Summary</name>
          <t indent="0" pn="section-8.2.3-1">Configured and Tunneled Remote ACP neighbors Neighbors are less "indestructible"
        than L2 adjacent ACP neighbors based on link local link-local addressing, since
        they depend on more correct Data-Plane data plane operations, such as routing and global addressing.</t>
          <t>Nevertheless,
          <t indent="0" pn="section-8.2.3-2">Nevertheless, these options may be crucial to incrementally deploy deploying
        the ACP, especially if it is meant to connect islands across the Internet.
        Implementations SHOULD <bcp14>SHOULD</bcp14> support at least Tunneled Remote ACP Neighbors
        via GRE tunnels - tunnels, which is likely the most common router-to-router
        tunneling protocol in use today.</t>
        </section>
      </section>
      <!-- remote-acp-neighbors-->
    </section>
    <!-- workarounds -->
    <section anchor="operational" numbered="true" toc="default">
      <name>ACP toc="include" removeInRFC="false" pn="section-9">
      <name slugifiedName="name-acp-operations-informative">ACP Operations (Informative)</name>
      <t>The
      <t indent="0" pn="section-9-1">The following sections document important operational aspects of the ACP. They are not normative because they do not impact the interoperability between components of the ACP, but they include recommendations/requirements recommendations and/or requirements for the internal operational model that are beneficial or necessary to achieve the desired use-case benefits of the ACP (see <xref target="usage" format="default"/>).</t> format="default" sectionFormat="of" derivedContent="Section 3"/>).</t>
      <ul spacing="compact">
        <li><xref spacing="normal" bare="false" empty="false" indent="3" pn="section-9-2">
        <li pn="section-9-2.1">
          <xref target="diagnostics" format="default"/> format="default" sectionFormat="of" derivedContent="Section 9.1"/> describes the recommended capabilities of operator diagnostics capabilities of ACP nodes.</li>
        <li><xref
        <li pn="section-9-2.2">
          <xref target="registrar-considerations" format="default"/> format="default" sectionFormat="of" derivedContent="Section 9.2"/> describes at a high level how an ACP registrar needs to work, what its configuration parameters are are, and specific issues impacting the choices of deployment design due to renewal and revocation issues. It describes a model where ACP Registrars registrars have their own sub-CA to provide the most distributed deployment option for ACP Registrars, registrars, and it describes considerations for centralized policy control of ACP Registrar registrar operations.</li>
        <li><xref
        <li pn="section-9-2.3">
          <xref target="enabling-acp" format="default"/> format="default" sectionFormat="of" derivedContent="Section 9.3"/> describes suggested ACP node behavior and operational interfaces (configuration options) to manage the ACP in so-called greenfield devices (previously unconfigured) and brownfield devices (preconfigured).</li>
      </ul>
      <t>The
      <t indent="0" pn="section-9-3">The recommendations and suggestions of this chapter were derived from operational experience gained with a commercially available pre-standard ACP implementation.</t>
      <section anchor="diagnostics" numbered="true" toc="default">
        <name>ACP toc="include" removeInRFC="false" pn="section-9.1">
        <name slugifiedName="name-acp-and-brski-diagnostics">ACP (and BRSKI) Diagnostics</name>
        <t>Even
        <t indent="0" pn="section-9.1-1">Even though ACP and ANI in general are taking out removing many manual configuration mistakes
through their automation, it is important to provide good diagnostics for them.</t>
        <t>Basic
        <t indent="0" pn="section-9.1-2">Basic standardized diagnostics would require support for (yang) (YANG) models representing the
complete (auto-)configuration (auto)configuration and operational state of all components: GRASP,
ACP
ACP, and the infrastructure used by them: them, such as TLS/DTLS, IPsec, certificates, TA, time,
VRF
VRF, and so on.  While necessary, this is not sufficient:</t>
        <t>Simply sufficient.</t>
        <t indent="0" pn="section-9.1-3">Simply representing the state of components does not allow operators to quickly take
action - -- unless they do understand how to interpret the data, and that which can mean a
requirement for deep understanding of all components and how they interact in the ACP/ANI.</t>
        <t>Diagnostic
        <t indent="0" pn="section-9.1-4">Diagnostic supports should help to quickly answer the questions operators
are expected to ask, such as "is "Is the ACP working correctly?", correctly?" or "why "Why is there no
ACP connection to a known neighboring node?"</t>
        <t>In
        <t indent="0" pn="section-9.1-5">In current network management approaches, the logic to answer these
questions is most often built as into centralized diagnostics software that leverages
the above mentioned data models.  While this approach is feasible for components
utilizing the ANI, it is not sufficient to diagnose the ANI itself:</t>
        <ul spacing="compact">
          <li>Developing spacing="normal" bare="false" empty="false" indent="3" pn="section-9.1-6">
          <li pn="section-9.1-6.1">Developing the logic to identify common issues requires operational experience
with the components of the ANI.  Letting each management system define its
own analysis is inefficient.</li>
          <li>When
          <li pn="section-9.1-6.2">When the ANI is not operating correctly, it may not be possible to run diagnostics
from remote
remotely because of missing connectivity.  The ANI should therefore have diagnostic
capabilities available locally on the nodes themselves.</li>
          <li>Certain
          <li pn="section-9.1-6.3">Certain operations are difficult or impossible to monitor in real-time, real time, such as
initial bootstrap issues in a network location where no capabilities exist to attach
local diagnostics.  Therefore, it is important to also define means of capturing (logging) how to capture (log)
diagnostics locally for later retrieval.  Ideally, these captures are also non-volatile nonvolatile so
that they can survive extended power-off conditions - conditions, for example example, when a device
that fails to be brought up zero-touch is being sent back for diagnostics at a
more appropriate location.</li>
        </ul>
        <t>The
        <t indent="0" pn="section-9.1-7">The simplest form of diagnostics for answering questions such as the above
is to represent the relevant information sequentially in dependency order,
so that the first non-expected/non-operational unexpected and/or nonoperational item is the most likely root
cause.  Or
cause, or just log/highlight that log and/or highlight that item.  For example:</t>
        <t>Q:
        <t indent="0" pn="section-9.1-8">Question: Is the ACP operational to accept neighbor connections: connections?
</t>
        <ul spacing="compact">
          <li>Check spacing="normal" bare="false" empty="false" indent="3" pn="section-9.1-9">
          <li pn="section-9.1-9.1">Check if any potentially the necessary configuration configurations to make ACP/ANI operational are correct (see <xref target="enabling-acp" format="default"/> format="default" sectionFormat="of" derivedContent="Section 9.3"/> for a discussion of such commands).</li>
          <li>Does
          <li pn="section-9.1-9.2">Does the system time look reasonable, or could it be the default system time after clock chip battery failure (certificate of the clock chip? Certificate checks depend on reasonable notion of time)?.</li>
          <li>Does time.</li>
          <li pn="section-9.1-9.3">Does the node have keying material - material, such as domain certificate, TA certificates, ...></li>
          <li>If etc.?</li>
          <li pn="section-9.1-9.4">If there is no keying material and the ANI is supported/enabled,
   check the state of BRSKI (not detailed in this example).</li>
          <li>
            <t>Check
          <li pn="section-9.1-9.5">
            <t indent="0" pn="section-9.1-9.5.1">Check the validity of the domain certificate:
            </t>
            <ul spacing="compact">
              <li>Does spacing="normal" bare="false" empty="false" indent="3" pn="section-9.1-9.5.2">
              <li pn="section-9.1-9.5.2.1">Does the certificate validate against the TA?</li>
              <li>Has
              <li pn="section-9.1-9.5.2.2">Has it been revoked?</li>
              <li>Was
              <li pn="section-9.1-9.5.2.3">Was the last scheduled attempt to retrieve a CRL successful successful? (e.g., do we know that our CRL information is up to date).</li>
              <li>Is date?)</li>
              <li pn="section-9.1-9.5.2.4">Is the certificate valid: valid? The validity start time is in the past, and the expiration time is in the future?</li>
              <li>Does
              <li pn="section-9.1-9.5.2.5">Does the certificate have a correctly formatted acp-node-name field?</li>
            </ul>
          </li>
          <li>Was
          <li pn="section-9.1-9.6">Was the ACP VRF successfully created?</li>
          <li>Is
          <li pn="section-9.1-9.7">Is ACP enabled on one or more interfaces that are up and running?</li>
        </ul>
        <t>If
        <t indent="0" pn="section-9.1-10">If all this of the above looks good, the ACP should be running locally "fine" - locally, but we did not check any ACP neighbor relationships.</t>
        <t>Question: why
        <t indent="0" pn="section-9.1-11">Question: Why does the node not create a working ACP connection to a neighbor on an interface?
</t>
        <ul spacing="compact">
          <li>Is spacing="normal" bare="false" empty="false" indent="3" pn="section-9.1-12">
          <li pn="section-9.1-12.1">Is the interface physically up? Does it have an IPv6 link-local address?</li>
          <li>Is
          <li pn="section-9.1-12.2">Is it enabled for ACP?</li>
          <li>Do
          <li pn="section-9.1-12.3">Do we successfully send DULL GRASP messages to the interface (link layer errors)?</li>
          <li>Do interface? (Are there link-layer errors?)</li>
          <li pn="section-9.1-12.4">Do we receive DULL GRASP messages on the interface? If not, some intervening L2 equipment performing bad MLD snooping could have caused problems.  Provide  Provide, e.g., diagnostics of the MLD querier IPv6 and MAC address.</li>
          <li>Do
          <li pn="section-9.1-12.5">Do we see the ACP objective in any DULL GRASP message from that interface? Diagnose the supported secure channel methods.</li>
          <li>Do
          <li pn="section-9.1-12.6">Do we know the MAC address of the neighbor with the ACP objective? If not, diagnose SLAAC/ND state.</li>
          <li>When
          <li pn="section-9.1-12.7">When did we last attempt to build an ACP secure channel to the neighbor?</li>
          <li>
            <t>If
          <li pn="section-9.1-12.8">
            <t indent="0" pn="section-9.1-12.8.1">If it failed, why: failed:
            </t>
            <ul spacing="compact">
              <li>Did spacing="normal" bare="false" empty="false" indent="3" pn="section-9.1-12.8.2">
              <li pn="section-9.1-12.8.2.1">Did the neighbor close the connection on us us, or did we close the connection on it because the domain certificate membership failed?</li>
              <li>If
              <li pn="section-9.1-12.8.2.2">If the neighbor closed the connection on us, provide any error diagnostics from the secure channel protocol.</li>
              <li>
                <t>If
              <li pn="section-9.1-12.8.2.3">
                <t indent="0" pn="section-9.1-12.8.2.3.1">If we failed the attempt, display our local reason:
                </t>
                <ul spacing="compact">
                  <li>There spacing="normal" bare="false" empty="false" indent="3" pn="section-9.1-12.8.2.3.2">
                  <li pn="section-9.1-12.8.2.3.2.1">There was no common secure channel protocol supported by the two neighbors (this could not happen on nodes supporting this specification because it mandates common support for IPsec).</li>
                  <li>
                    <t>The
                  <li pn="section-9.1-12.8.2.3.2.2">
                    <t indent="0" pn="section-9.1-12.8.2.3.2.2.1">Did the ACP certificate membership check (<xref target="certcheck" format="default"/>) fails: format="default" sectionFormat="of" derivedContent="Section 6.2.3"/>) fail?
                    </t>
                    <ul spacing="compact">
                      <li>The spacing="normal" bare="false" empty="false" indent="3" pn="section-9.1-12.8.2.3.2.2.2">
                      <li pn="section-9.1-12.8.2.3.2.2.2.1">The neighbor's certificate is not signed directly or indirectly by one of the nodes node's TA.  Provide diagnostics which TA it has (can identify whom the device belongs to).</li>
                      <li>The
                      <li pn="section-9.1-12.8.2.3.2.2.2.2">The neighbor's certificate does not have the same domain (or no domain at all).  Diagnose domain-name acp-domain-name and potentially other cert info.</li>
                      <li>The
                      <li pn="section-9.1-12.8.2.3.2.2.2.3">The neighbor's certificate has been revoked or could not be authenticated by OCSP. </li>
                      <li>The
                      <li pn="section-9.1-12.8.2.3.2.2.2.4">The neighbor's certificate has expired - expired, or it is not yet valid.</li>
                    </ul>
                  </li>
                </ul>
              </li>
              <li>Any
              <li pn="section-9.1-12.8.2.4">Are there any other connection issues in issues, e.g., IKEv2 / IPsec, DTLS?.</li> IKEv2/IPsec, DTLS?</li>
            </ul>
          </li>
        </ul>
        <t>Question:
        <t indent="0" pn="section-9.1-13">Question: Is the ACP operating correctly across its secure channels?
</t>
        <ul spacing="compact">
          <li>Are spacing="normal" bare="false" empty="false" indent="3" pn="section-9.1-14">
          <li pn="section-9.1-14.1">Are there one or more active ACP neighbors with secure channels?</li>
          <li>Is the
          <li pn="section-9.1-14.2">Is RPL routing protocol for the ACP running?</li>
          <li>Is
          <li pn="section-9.1-14.3">Is there a default route to the root in the ACP routing table?</li>
          <li>Is there
          <li pn="section-9.1-14.4">Is there, for each direct ACP neighbor not reachable over the ACP virtual interface to the root root, a route in the ACP routing table?</li>
          <li>Is
          <li pn="section-9.1-14.5">Is ACP GRASP running?</li>
          <li>Is
          <li pn="section-9.1-14.6">Is at least one SRV.est "SRV.est" objective cached (to support certificate renewal)?</li>
          <li>Is
          <li pn="section-9.1-14.7">Is there at least one BRSKI registrar objective cached (in case cached? (If BRSKI is supported)</li>
          <li>Is supported.)</li>
          <li pn="section-9.1-14.8">Is the BRSKI proxy operating normally on all interfaces where ACP is operating?</li>
          <li>...</li>
        </ul>
        <t>These
        <t indent="0" pn="section-9.1-15">These lists are not necessarily complete, but they illustrate the principle and show that there are variety of issues ranging from normal operational causes (a neighbor in another ACP domain) over to problems in the credentials management (certificate lifetimes), to explicit security actions (revocation) or unexpected connectivity issues (intervening L2 equipment).</t>
        <t>The
        <t indent="0" pn="section-9.1-16">The items so far are illustrating illustrate how the ANI operations can
be diagnosed with passive observation of the operational state
of its components including historic/cached/counted historic, cached, and/or counted events.  This is
not necessary necessarily sufficient to provide good enough diagnostics overall:</t>
        <t>The overall.</t>
        <t indent="0" pn="section-9.1-17">The components of ACP and BRSKI are designed with security in mind mind,
but they do not attempt to provide diagnostics for building the
network itself.  Consider two examples:
</t>
        <ol type="1" spacing="compact">
          <li>BRSKI spacing="normal" indent="adaptive" start="1" pn="section-9.1-18">
          <li pn="section-9.1-18.1" derivedCounter="1.">BRSKI does not allow for a neighboring
    device to identify the pledges pledge's IDevID certificate.  Only the selected
    BRSKI registrar can do this, but it may be difficult to disseminate
    information about undesired pledges from those BRSKI registrars about undesired pledges to locations/nodes locations and/or nodes
    where information about those pledges is desired.</li>
          <li>LLDP
          <li pn="section-9.1-18.2" derivedCounter="2.">LLDP disseminates information about nodes to their immediate neighbors, nodes,
    such as node model/type/software model, type, and/or software and interface name/number name and/or number of the
    connection.
    connection, to their immediate neighbors.  This information is often helpful or even necessary
    in network diagnostics.  It can equally be considered to be too insecure
    to make this information available unprotected to all possible neighbors.</li>
        </ol>
        <t>An
        <t indent="0" pn="section-9.1-19">An "interested adjacent party" can always determine the IDevID certificate of a BRSKI pledge
by behaving like a BRSKI proxy/registrar.  Therefore, the IDevID certificate of a BRSKI pledge
is not meant to be protected - -- it just has to be queried and is not
signaled unsolicited (as it would be in LLDP) so that other observers
on the same subnet can determine who is an "interested adjacent party".</t>
        <section anchor="ta-troubleshoot" numbered="true" toc="default">
          <name>Secure toc="include" removeInRFC="false" pn="section-9.1.1">
          <name slugifiedName="name-secure-channel-peer-diagnos">Secure Channel Peer diagnostics</name>
          <t>When Diagnostics</name>
          <t indent="0" pn="section-9.1.1-1">When using mutual certificate authentication, the TA certificate is not required
to be signaled explicitly because its hash is sufficient for certificate
chain validation.  In the case of ACP secure channel setup setup, this leads
to limited diagnostics when authentication fails because of TA mismatch.
For this reason, <xref target="common-requirements" format="default"/> format="default" sectionFormat="of" derivedContent="Section 6.8.2"/> recommends to also include including the TA certificate in the
secure channel signaling. This should be possible
to do without protocol modifications in modifying the security association protocols used by the
ACP. For example, while <xref target="RFC7296" format="default"/> format="default" sectionFormat="of" derivedContent="RFC7296"/> does not mention this, it
also does not prohibit it.</t>
          <t>One
          <t indent="0" pn="section-9.1.1-2">One common deployment use case where the diagnostic diagnostics through the signaled
TA of a candidate peer is are very helpful are is the multi-tenant environments environment, such as
an office buildings, building, where different tenants run their own networks and ACPs.
Each tenant is given supposedly disjoint L2 connectivity through the building infrastructure.
In these environments environments, there are various common errors through which a device may
receive L2 connectivity into the wrong tenants tenant's network.</t>
          <t>While
          <t indent="0" pn="section-9.1.1-3">While the ACP itself is not impact impacted by this, the Data-Plane data plane to be built later may be
impacted. Therefore, it is important to be able to diagnose such undesirable
connectivity from the ACP so that any autonomic or non-autonomic mechanisms
to configure the Data-Plane data plane can accordingly treat such interfaces. interfaces accordingly.
The information in the TA of the peer can then ease
troubleshooting of such issues.</t>
          <t>Another example
          <t indent="0" pn="section-9.1.1-4">Another use case is the intended or accidental re-activation reactivation of equipment
whose TA certificate has long expired, equipment,
such as redundant gear taken from storage
after years.</t>
          <t>A storage, whose TA certificate has long expired.</t>
          <t indent="0" pn="section-9.1.1-5">A third example use case is when when, in a mergers &amp; merger and acquisition case case, ACP nodes have not
been correctly provisioned with the mutual TA of a previously disjoint ACP. This
is assuming
assumes that the ACP domain names where were already aligned so that the ACP
domain membership check is only failing on the TA.</t>
          <t>A
          <t indent="0" pn="section-9.1.1-6">A fourth example use case is when multiple registrars where are set up for the same
ACP but without are not correctly setting set up with the same TA. For example, when registrars
support to also be CA being CAs themselves but are misconfigured to become TA TAs instead
of intermediate CA.</t> CAs.</t>
        </section>
      </section>
      <section anchor="registrar-considerations" numbered="true" toc="default">
        <name>ACP toc="include" removeInRFC="false" pn="section-9.2">
        <name slugifiedName="name-acp-registrars-2">ACP Registrars</name>
        <t>As
        <t indent="0" pn="section-9.2-1">As described in <xref target="acp-registrars" format="default"/>, format="default" sectionFormat="of" derivedContent="Section 6.11.7"/>, the ACP addressing
mechanism is designed to enable lightweight, distributed distributed, and uncoordinated
ACP registrars that are providing provide ACP address prefixes to candidate ACP
nodes by enrolling them with an ACP certificate into an ACP domain via
any appropriate mechanism/protocol, mechanism and/or protocol, automated or not.</t>
        <t>This
        <t indent="0" pn="section-9.2-2">This section discusses informatively more details and options for ACP registrars.</t>
        <section anchor="reg-interact" numbered="true" toc="default">
          <name>Registrar interactions</name>
          <t>This toc="include" removeInRFC="false" pn="section-9.2.1">
          <name slugifiedName="name-registrar-interactions">Registrar Interactions</name>
          <t indent="0" pn="section-9.2.1-1">This section summarizes and discusses the interactions with other entities required
by an ACP registrar.</t>
          <t>In
          <t indent="0" pn="section-9.2.1-2">In a simple instance of an ACP network, no central NOC component beside
a TA is required. Typically, this is a root CA.  One or more uncoordinated acting
ACP registrar registrars can be set up, performing the following interactions:</t>
          <t>To interactions.</t>
          <t indent="0" pn="section-9.2.1-3">To orchestrate enrolling a candidate ACP node autonomically,
the ACP registrar can rely on the ACP and use Proxies proxies to reach the candidate ACP node,
therefore allowing minimum pre-existing (auto-)configured minimal, preexisting (auto)configured network services
on the candidate ACP node.  BRSKI defines the BRSKI proxy, a design that can be
adopted for various protocols that Pledges/candidate pledges and/or candidate ACP nodes could want to use,
for example example, BRSKI over CoAP (Constrained Application Protocol), Protocol) or the proxying of
NETCONF.</t>
          <t>To
          <t indent="0" pn="section-9.2.1-4">To reach a TA that has no ACP connectivity, the ACP registrar would use uses
the Data-Plane. data plane. The ACP and Data-Plane data plane in an ACP registrar could (and by default
should be)
should) be completely isolated from each other at the network level.
Only applications such as the ACP registrar would need the ability for
 their transport stacks to access both.</t>
          <t>In
          <t indent="0" pn="section-9.2.1-5">In non-autonomic enrollment options, the Data-Plane data plane
between a an ACP registrar and the candidate ACP node needs to be configured
first.  This includes the ACP registrar and the candidate ACP node.
Then any appropriate set of protocols can be used between the ACP registrar and
the candidate ACP node to discover the other side, and then connect
and enroll (configure) the candidate ACP node with an ACP certificate.
For example, NETCONF ZeroTouch (<xref Zero Touch ("<xref target="RFC8572" format="title" sectionFormat="of" derivedContent="Secure Zero Touch Provisioning (SZTP)"/>" <xref target="RFC8572" format="default"/>) format="default" sectionFormat="of" derivedContent="RFC8572"/>)
is an example a protocol that could be used for this.  BRSKI using optional
discovery mechanisms is equally a possibility for candidate ACP nodes
attempting to be enrolled across non-ACP networks, such as the Internet.</t>
          <t>When
          <t indent="0" pn="section-9.2.1-6">When a candidate ACP nodes have secure bootstrap, node, such as a BRSKI Pledges,
they pledge, has secure bootstrap,
it will not trust to be configured/enrolled being configured and/or enrolled across the network, network unless
being
it is presented with a voucher (see "<xref target="RFC8366" format="title" sectionFormat="of" derivedContent="A Voucher Artifact for Bootstrapping Protocols"/>" <xref target="RFC8366" format="default"/>) format="default" sectionFormat="of" derivedContent="RFC8366"/>) authorizing
the network to take possession of the node. An ACP registrar will then need a
method to retrieve such a voucher, either offline, offline or online from a MASA
(Manufacturer Authorized Signing Authority). BRSKI and NETCONF
ZeroTouch
Zero Touch are two protocols that include capabilities to present the voucher
to the candidate ACP node.</t>
          <t>An
          <t indent="0" pn="section-9.2.1-7">An ACP registrar could operate EST for ACP certificate renewal and/or
act as a CRL Distribution point. Point. A node performing these
services does not need to support performing (initial) enrollment, but
it does require the same above described connectivity as an ACP
registrar: via the ACP to the ACP nodes and via the Data-Plane data plane to the TA
and other sources of CRL information.</t>
        </section>
        <section anchor="reg-config" numbered="true" toc="default">
          <name>Registrar Parameter</name>
          <t>The toc="include" removeInRFC="false" pn="section-9.2.2">
          <name slugifiedName="name-registrar-parameters">Registrar Parameters</name>
          <t indent="0" pn="section-9.2.2-1">The interactions of an ACP registrar outlined in <xref target="acp-registrars" format="default"/> format="default" sectionFormat="of" derivedContent="Section 6.11.7"/> and
<xref target="reg-interact" format="default"/> above format="default" sectionFormat="of" derivedContent="Section 9.2.1"/> depend on the following parameters:
</t>
          <ul spacing="compact">
            <li>A spacing="normal" bare="false" empty="false" indent="3" pn="section-9.2.2-2">
            <li pn="section-9.2.2-2.1">A URL to the TA and credentials so that the ACP
   registrar can let the TA sign candidate ACP node certificates.</li>
            <li>The
            <li pn="section-9.2.2-2.2">The ACP domain-name.</li>
            <li>The domain name.</li>
            <li pn="section-9.2.2-2.3">The Registrar-ID to use. This could default to a MAC address of the ACP registrar.</li>

            <li>For
            <li pn="section-9.2.2-2.4">For recovery, the next-useable next usable Node-IDs for zone (Zone-ID=0) sub-addressing scheme,
     for Vlong /112 the Zone Addressing Sub-Scheme (Zone-ID 0)
     and for the Vlong /120 sub-addressing scheme. Addressing Sub-Scheme (/112 and /120). These IDs would only need
     to be provisioned after recovering from a crash. Some other mechanism would
     be required to remember these IDs in a backup location or to recover them
     from the set of currently known ACP nodes.</li>

            <li>Policies if
            <li pn="section-9.2.2-2.5">Policies on whether the candidate ACP nodes should receive a domain certificate or not,
     for example example, based on the devices device's IDevID certificate as in BRSKI. The ACP registrar may have
     a
     whitelist or blacklist of devices based on a device's "serialNumber" attribute <xref target="X.520" format="default"/>  "serialNumbers" attribute format="default" sectionFormat="of" derivedContent="X.520"/> in the subject field distinguished name encoding from their of its IDevID certificate.</li>

            <li>Policies
            <li pn="section-9.2.2-2.6">Policies on what type of address prefix to assign to a candidate ACP devices, device,
     likely based on likely the same information.</li>
            <li>For
            <li pn="section-9.2.2-2.7">For BRSKI or other mechanisms using vouchers: Parameters parameters to determine
     how to retrieve vouchers for specific type types of secure bootstrap candidate
     ACP nodes (such as MASA URLs), unless this information is automatically
     learned
     learned, such as from the IDevID certificate of candidate ACP nodes (as defined in BRSKI).</li>
          </ul>
        </section>
        <section anchor="cert-renewal" numbered="true" toc="default">
          <name>Certificate renewal toc="include" removeInRFC="false" pn="section-9.2.3">
          <name slugifiedName="name-certificate-renewal-and-lim">Certificate Renewal and limitations</name>
          <t>When Limitations</name>
          <t indent="0" pn="section-9.2.3-1">When an ACP node renews/rekeys renews and/or rekeys its certificate, it may end up doing so via
a different registrar (e.g., EST server) than the one it originally received
its ACP certificate from, for example example, because that original ACP registrar
is gone. The ACP registrar through which the renewal/rekeying is performed
would by default trust the acp-node-name from the ACP nodes node's current
ACP certificate and maintain this information so that the ACP node
maintains its ACP address prefix. In EST renewal/rekeying, the ACP nodes node's current
ACP certificate is signaled during the TLS handshake.</t>
          <t>This
          <t indent="0" pn="section-9.2.3-2">This simple scenario has two limitations:
</t>
          <ol type="1" spacing="compact">
            <li>The spacing="normal" indent="adaptive" start="1" pn="section-9.2.3-3">
            <li pn="section-9.2.3-3.1" derivedCounter="1.">The ACP registrars registrar cannot directly assign certificates to nodes and
     therefore needs an "online" connection to the TA.</li>
            <li>Recovery
            <li pn="section-9.2.3-3.2" derivedCounter="2.">Recovery from a compromised ACP registrar is difficult.
     When an ACP registrar is compromised, it can insert insert, for example example,
     a conflicting acp-node-name and create thereby create an attack
     against other ACP nodes through the ACP routing protocol.</li>
          </ol>
          <t>Even
          <t indent="0" pn="section-9.2.3-4">Even when such a malicious ACP registrar is detected, resolving the
problem may be difficult because it would require identifying all the
wrong ACP certificates assigned via the ACP registrar after it
was compromised. And without Without additional centralized tracking of assigned
certificates
certificates, there is no way to do this.</t>
        </section>
        <section anchor="sub-ca" numbered="true" toc="default">
          <name>ACP toc="include" removeInRFC="false" pn="section-9.2.4">
          <name slugifiedName="name-acp-registrars-with-sub-ca">ACP Registrars with sub-CA</name>
          <t>In situations, Sub-CA</name>
          <t indent="0" pn="section-9.2.4-1">In situations where either of the above two limitations are an issue,
ACP registrars could also be sub-CAs. This removes the need for
connectivity to a TA whenever an ACP node is enrolled, and it reduces
the need for connectivity of such an ACP registrar to a TA to only
those times when it needs to renew its own certificate. The ACP registrar
would also now use its own (sub-CA) certificate to enroll and sign the
ACP nodes node's certificates, and therefore it is only necessary to revoke
a compromised ACP registrars registrar's sub-CA certificate. Alternatively Alternatively, one can
let it expire and not renew it, it when the certificate of the sub-CA is appropriately
short-lived.</t>
          <t>As
          <t indent="0" pn="section-9.2.4-2">As the ACP domain membership check verifies a
peer ACP node's ACP certificate trust chain, it will also verify
the signing certificate certificate, which is the compromised/revoked compromised and/or revoked sub-CA certificate.
Therefore, ACP domain membership for an ACP node enrolled from by a
compromised and discovered ACP registrar will fail.</t>
          <t>ACP
          <t indent="0" pn="section-9.2.4-3">ACP nodes enrolled by a compromised ACP registrar
would automatically fail to establish ACP channels and ACP domain
certificate renewal via EST and therefore revert to their role as
a
candidate ACP members and attempt to get a new ACP certificate
from an ACP registrar - registrar, for example, via BRSKI. In As a result, ACP registrars that have an
associated sub-CA makes make isolating and resolving issues with
compromised registrars easier.</t>
          <t>Note
          <t indent="0" pn="section-9.2.4-4">Note that ACP registrars with sub-CA functionality also can control the
lifetime of ACP certificates easier more easily and therefore also can be used as
a tool to introduce short lived short-lived certificates and not to no longer rely on CRL,
whereas the certificates for the sub-CAs themselves could be longer
lived and subject to CRL.</t>
        </section>
        <section anchor="pms" numbered="true" toc="default">
          <name>Centralized toc="include" removeInRFC="false" pn="section-9.2.5">
          <name slugifiedName="name-centralized-policy-control">Centralized Policy Control</name>
          <t>When
          <t indent="0" pn="section-9.2.5-1">When using multiple, uncoordinated ACP registrars, several advanced
operations are potentially more complex than with a single, resilient
 policy control backend, for example example, including but not limited to: to the following:
</t>
          <ul spacing="compact">
            <li>Which spacing="normal" bare="false" empty="false" indent="3" pn="section-9.2.5-2">
            <li pn="section-9.2.5-2.1">Deciding which candidate ACP node is permitted or not permitted into an
     ACP domain. This may not be a decision to be taken made upfront, so that
     a policy per "serialNumber" attribute in the subject field distinguished name encoding  can be loaded into every ACP registrar.
     Instead, it may better be decided in real-time including real time, potentially including
     a human decision in a NOC.</li>
            <li>Tracking of
            <li pn="section-9.2.5-2.2">Tracking all enrolled ACP nodes and their certificate information.
     For example, in support of revoking an individual ACP nodes node's certificates.</li>
            <li>More
            <li pn="section-9.2.5-2.3">Needing more flexible policies what as to which type of address prefix or even what which specific
     address prefix to assign to a candidate ACP node.</li>
          </ul>
          <t>These
          <t indent="0" pn="section-9.2.5-3">These and other operations could be introduced more easily by
introducing a centralized Policy Management System (PMS) and modifying
ACP registrar behavior so that it queries the PMS for any policy decision
occurring during the candidate ACP node enrollment process and/or the
ACP node certificate renewal process. For process, for example, which ACP address
prefix to assign. Likewise Likewise, the ACP registrar would report any relevant state
change information to the PMS as well, for example example, when a certificate
was successfully enrolled onto a candidate ACP node.</t>
        </section>
      </section>
      <section anchor="enabling-acp" numbered="true" toc="default">
        <name>Enabling toc="include" removeInRFC="false" pn="section-9.3">
        <name slugifiedName="name-enabling-and-disabling-the-">Enabling and disabling ACP/ANI</name>
        <t> Disabling the ACP and/or the ANI</name>
        <t indent="0" pn="section-9.3-1"> Both ACP and BRSKI require interfaces to be operational enough to support sending/receiving the sending and receiving of their packets.  In node types where interfaces are enabled by default (e.g., without operator configuration) enabled, configuration), such as most L2 switches, this would be less of a change in behavior than in most L3 devices (e.g. (e.g., routers), where interfaces are disabled by default disabled. default.  In almost all network devices devices, though, it is common though for configuration to change interfaces to a physically disabled state state, and that this would break the ACP.</t>
        <t>In
        <t indent="0" pn="section-9.3-2">In this section, we discuss a suggested operational model to enable/disable enable and disable interfaces and nodes for ACP/ANI in a way that minimizes the risk of operator action to break breaking the ACP in this way, due to operator action and that also minimizes operator surprise when the ACP/ANI becomes supported in node software.</t>
        <section anchor="secure-enabling" numbered="true" toc="default">
          <name>Filtering for non-ACP/ANI packets</name>
          <t>Whenever toc="include" removeInRFC="false" pn="section-9.3.1">
          <name slugifiedName="name-filtering-for-non-acp-ani-p">Filtering for Non-ACP/ANI Packets</name>
          <t indent="0" pn="section-9.3.1-1">Whenever this document refers to enabling an interface for ACP (or BRSKI), it only requires to permit permitting the interface to send/receive send and receive packets necessary to operate ACP (or BRSKI) - -- but not any other Data-Plane data plane packets.  Unless the Data-Plane data plane is explicitly configured/enabled, configured and enabled, all packets that are not required for ACP/BRSKI should be filtered on input and output:</t>
          <t>Both output.</t>
          <t indent="0" pn="section-9.3.1-2">Both BRSKI and ACP require link-local only link-local-only IPv6 operations on interfaces and DULL GRASP.  IPv6 link-local operations means mean the minimum signaling to auto-assign an IPv6 link-local address and talk to neighbors via their link-local address: addresses: SLAAC (Stateless Address Auto-Configuration - <xref target="RFC4862" format="default"/>) format="default" sectionFormat="of" derivedContent="RFC4862"/> and ND (Neighbor Discovery - <xref target="RFC4861" format="default"/>). format="default" sectionFormat="of" derivedContent="RFC4861"/>.  When the device is a BRSKI pledge, it may also require TCP/TLS connections to BRSKI proxies on the interface.  When the device has keying material, and the ACP is running, it requires DULL GRASP packets and packets necessary for the secure-channel secure channel mechanism it supports, e.g., IKEv2 and IPsec ESP packets or DTLS packets to the IPv6 link-local address of an ACP neighbor on the interface.  It also requires TCP/TLS packets for its BRSKI proxy functionality, functionality if it does support supports BRSKI.</t>
        </section>
        <section anchor="admin-down" numbered="true" toc="default">
          <name>Admin Down toc="include" removeInRFC="false" pn="section-9.3.2">
          <name slugifiedName="name-admin-down-state">"admin down" State</name>
          <t>Interfaces
          <t indent="0" pn="section-9.3.2-1">Interfaces on most network equipment have at least two states: "up" and "down".  These may have product specific product-specific names.  For example, "down" for example could be called "shutdown" "shutdown", and "up" could be called "no shutdown".  The "down" state disables all interface operations down to the physical level.  The "up" state enables the interface enough for all possible L2/L3 services to operate on top of it it, and it may also auto-enable some subset of them.  More commonly, the operations of various L2/L3 services is are controlled via additional node-wide or interface level interface-level options, but they all become only active only when the interface is not "down".  Therefore, an easy way to ensure that all L2/L3 operations on an interface are inactive is to put the interface into "down" state.  The fact that this also physically shuts down the interface is in many cases just a side effect, effect in many cases, but it may be important in other cases (see below, <xref target="down-fast-state-propagation" format="default"/>).</t>
          <t>One of the format="default" sectionFormat="of" derivedContent="Section 9.3.2.2"/>).</t>
          <t indent="0" pn="section-9.3.2-2">A common problems problem of remote management is for the operator or SDN controller to cut cutting its own connectivity to the remote node by a configuration via configuration, impacting its own management connection into to the node. The ACP itself should have no dedicated configuration other than the aforementioned enablement enabling of the ACP on brownfield ACP nodes. This leaves configuration that cannot distinguish between the ACP and Data-Plane data plane as sources of configuration mistakes as these commands will impact the ACP even though they should only impact the Data-Plane.</t>
          <t>The data plane.</t>
          <t indent="0" pn="section-9.3.2-3">The one ubiquitous type of commands command that do does this on many type types of routers are is the interface "down" commands/configurations. command/configuration. When such a command is applied to the interface through which the ACP provides access for remote management management, it would cut cuts the remote management connection through the ACP because, as outlined above, the "down" commands command typically impact impacts the physical layer too layer, too, and not only the Data-Plane data plane services.</t>
          <t>To
          <t indent="0" pn="section-9.3.2-4">To provide ACP/ANI resilience against such operator misconfiguration, this document
recommends to separate separating the "down" state of interfaces into an "admin down" state state, where the physical layer is kept running and the ACP/ANI can use the interface interface, and a "physical down" state.  Any existing "down" configurations would map to "admin down".  In "admin down", any existing L2/L3 services of the Data-Plane data plane should see no difference to "physical down" state.  To ensure that no Data-Plane data plane packets could be sent/received, sent or received, packet filtering could be established automatically as described above in <xref target="secure-enabling" format="default"/>.</t>
          <t>An format="default" sectionFormat="of" derivedContent="Section 9.3.1"/>.</t>
          <t indent="0" pn="section-9.3.2-5">An example of non-ACP ANI, but ANI not ACP, traffic that should be permitted to pass even in "admin-down" "admin down" state is BRSKI enrollment traffic between a BRSKI pledge and a BRSKI proxy.</t>
          <t>As necessary (see discussion below) new
          <t indent="0" pn="section-9.3.2-6">New configuration options could be introduced as necessary (see discussion below) to issue "physical down".  The options should be provided with additional checks to minimize the risk of issuing them in a way that breaks the ACP without automatic restoration.  For example, they could be denied  Examples of checks include not allowing the option to be issued from a control connection (NETCONF/SSH) that goes across the interface itself ("do not disconnect yourself").  Or they could be performed only temporary and yourself") or only be made permanent with applying the option after additional later reconfirmation.</t>
          <t>In the
          <t indent="0" pn="section-9.3.2-7">The following sub-sections subsections discuss important aspects to of the introduction of "admin down" state are discussed.</t> state.</t>
          <section anchor="down-security" numbered="true" toc="default">
            <name>Security</name>
            <t>Interfaces toc="include" removeInRFC="false" pn="section-9.3.2.1">
            <name slugifiedName="name-security-2">Security</name>
            <t indent="0" pn="section-9.3.2.1-1">Interfaces are physically brought down (or left in default down "down" state) as a form of security.
"Admin
The "admin down" state as described above also provides also a high level of security
because it only permits ACP/ANI operations operations, which are both well secured.  Ultimately, it is subject to
the deployment's security review for the deployment  whether "admin down" is a feasible replacement for "physical down".</t>
            <t>The
            <t indent="0" pn="section-9.3.2.1-2">The need to trust the security of ACP/ANI operations needs to be weighed against
the operational benefits of permitting this: Consider the following: consider the typical example of a CPE (customer
premises equipment) with no on-site network expert.  User ports are in physical
down "physical
down" state unless explicitly configured not to be.  In a misconfiguration situation, the uplink
connection is incorrectly plugged into such as a user port.  The device is disconnected from the
network
network, and therefore no diagnostics from the network side is possible anymore. are no longer possible.
Alternatively, all ports default to "admin down".  The ACP (but not the Data-Plane) data plane) would
still automatically form.  Diagnostics from the network side is possible are possible, and operator
reaction could include to either to make this port the operational uplink port or to instruct
re-cabling.  Security wise, only the ACP/ANI could be attacked, all other functions are filtered
on interfaces in "admin down" state.</t>
          </section>
          <section anchor="down-fast-state-propagation" numbered="true" toc="default">
            <name>Fast state propagation toc="include" removeInRFC="false" pn="section-9.3.2.2">
            <name slugifiedName="name-fast-state-propagation-and-">Fast State Propagation and Diagnostics</name>
            <t>"Physical
            <t indent="0" pn="section-9.3.2.2-1">The "physical down" state propagates on many interface types (e.g., Ethernet) to the other side.
This can trigger fast L2/L3 protocol reaction on the other side side, and "admin down" would not
have the same (fast) result.</t>
            <t>Bringing
            <t indent="0" pn="section-9.3.2.2-2">Bringing interfaces to "physical down" state is is, to the best of our knowledge knowledge, always
a result of operator action, but action and, today, never the result of autonomic L2/L3 services
running on the nodes.  Therefore, one option is to change end the operator action to not
rely operator's reliance
on link-state interface state propagation anymore. via the subnet link or physical layer.  This may not be possible when both sides are
under the control of different operator control, operators, but in that case case, it is unlikely that the ACP is running
across the link link, and actually putting the interface into "physical down" state may
still be a good option.</t>
            <t>Ideally,
            <t indent="0" pn="section-9.3.2.2-3">Ideally, fast physical state propagation is replaced by fast software driven software-driven state
propagation.  For example, a DULL GRASP "admin-state" objective could be used to auto configure autoconfigure
a Bidirectional BFD session ("<xref target="RFC5880" format="title" sectionFormat="of" derivedContent="Bidirectional Forwarding Protocol (BFD, Detection (BFD)"/>" <xref target="RFC5880" format="default"/>) session format="default" sectionFormat="of" derivedContent="RFC5880"/>) between the two sides of the link that would be used to propagate the
"up" vs. admin down "admin down" state.</t>
            <t>Triggering physical down
            <t indent="0" pn="section-9.3.2.2-4">Triggering "physical down" state may also be used as a mean means of diagnosing cabling issues
in the absence of easier methods.  It is more complex than automated neighbor diagnostics
because it requires coordinated remote access to both (likely) both sides of a link to
determine whether up/down toggling will cause the same reaction on the remote side.</t>
            <t>See
            <t indent="0" pn="section-9.3.2.2-5">See <xref target="diagnostics" format="default"/> format="default" sectionFormat="of" derivedContent="Section 9.1"/> for a discussion about how LLDP and/or diagnostics
via GRASP could be used to provide neighbor diagnostics, diagnostics and therefore hopefully
eliminating
eliminate the need for "physical down" for neighbor diagnostics - -- as long as both
neighbors support ACP/ANI.</t>
          </section>
          <section anchor="low-level-link" numbered="true" toc="default">
            <name>Low Level toc="include" removeInRFC="false" pn="section-9.3.2.3">
            <name slugifiedName="name-low-level-link-diagnostics">Low-Level Link Diagnostics</name>
            <t>"Physical
            <t indent="0" pn="section-9.3.2.3-1">The "physical down" state is performed used to diagnose low-level interface behavior when higher layer higher-layer services (e.g., IPv6) are not working.  Especially  Ethernet links are especially subject to a wide variety of possible wrong configuration/cablings incorrect configurations/cablings if they do not support automatic selection of variable parameters such as speed (10/100/1000 Mbps), crossover (Auto-MDIX) (automatic medium-dependent interface crossover (MDI-X)), and connector (fiber, copper - -- when interfaces have multiple but can only enable one at a time).  The need for low level low-level link diagnostic diagnostics can therefore be minimized by using fully auto configuring autoconfiguring links.</t>
            <t>In
            <t indent="0" pn="section-9.3.2.3-2">In addition to "Physical down", low level the "physical down" state, low-level diagnostics of Ethernet or other interfaces also involve the creation of other states on interfaces, such as physical Loopback loopback (internal and/or external) or the bringing down of all packet transmissions for reflection/cable-length reflection and/or cable-length measurements.  Any of these options would disrupt ACP as well.</t>
            <t>In
            <t indent="0" pn="section-9.3.2.3-3">In cases where such low-level diagnostics of an operational link is are desired but where the link could be a single point of failure for the ACP, the ASA on both nodes of the link could perform a negotiated diagnostic that automatically terminates in a predetermined manner without dependence on external input input, ensuring the link will become operational again.</t>
          </section>
          <section anchor="power-consumption" numbered="true" toc="default">
            <name>Power toc="include" removeInRFC="false" pn="section-9.3.2.4">
            <name slugifiedName="name-power-consumption-issues">Power Consumption Issues</name>
            <t>Power
            <t indent="0" pn="section-9.3.2.4-1">Power consumption of "physical down" interfaces, interfaces may be significantly lower than those
in "admin down" state, for example example, on long-range fiber interfaces. Bringing up
interfaces, for example example, to probe reachability, reachability may also consume additional power. This
can make these type types of interfaces inappropriate to operate purely for the ACP when
they are not currently needed for the Data-Plane.</t> data plane.</t>
          </section>
        </section>
        <section anchor="if-enable" numbered="true" toc="default">
          <name>Interface level ACP/ANI enable</name>
          <t>The interface level toc="include" removeInRFC="false" pn="section-9.3.3">
          <name slugifiedName="name-enabling-interface-level-ac">Enabling Interface-Level ACP and ANI</name>
          <t indent="0" pn="section-9.3.3-1">The interface-level configuration option "ACP enable" enables ACP  operations on an interface, starting with ACP neighbor discovery via DULL GRAP.  GRASP.  The interface level interface-level configuration option "ANI enable" on nodes supporting BRSKI and ACP starts with BRSKI pledge operations when there is no domain certificate on the node.  On ACP/BRSKI nodes, "ACP only "ANI enable" may not need to be supported, but only "ANI supported and not "ACP enable".  Unless overridden by global configuration options (see later), "ACP/ANI <xref target="if-enable-auto" format="default" sectionFormat="of" derivedContent="Section 9.3.4"/>), either "ACP enable" or "ANI enable" (both abbreviated as "ACP/ANI enable")  will result in the "down" state on an interface to behave behaving as "admin down".</t>
        </section>
        <section anchor="if-enable-auto" numbered="true" toc="default">
          <name>Which interfaces to auto-enable?</name>
          <t>(<xref toc="include" removeInRFC="false" pn="section-9.3.4">
          <name slugifiedName="name-which-interfaces-to-auto-en">Which Interfaces to Auto-Enable?</name>
          <t indent="0" pn="section-9.3.4-1"><xref target="discovery-grasp" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 6.4"/> requires that "ACP enable" is automatically set on native interfaces, but not on non-native interfaces (reminder: a native interface is one that exists without operator configuration action action, such as physical interfaces in physical devices).</t>
          <t>Ideally, ACP enable
          <t indent="0" pn="section-9.3.4-2">Ideally, "ACP enable" is set automatically on all interfaces that provide access to additional connectivity that connectivity, which allows to reach more nodes of the ACP domain. domain to be reached.  The best set of interfaces necessary to achieve this is not possible to determine automatically.  Native interfaces are the best automatic approximation.</t>
          <t>Consider
          <t indent="0" pn="section-9.3.4-3">Consider an ACP domain of ACP nodes transitively connected via native interfaces.  A Data-Plane data plane tunnel between two of these nodes that are non-adjacent nonadjacent is created created, and "ACP enable" is set for that tunnel.  ACP RPL sees this tunnel as just as a single hop.  Routes in the ACP would use this hop as an attractive path element to connect regions adjacent to the tunnel nodes.  In  As a result, the actual hop-by-hop paths used by traffic in the ACP can become worse.  In addition, correct forwarding in the ACP now depends on correct Data-Plane data plane forwarding config configuration including QoS, filtering filtering, and other security on the Data-Plane data plane path across which this tunnel runs.  This is the main issue reason why "ACP/ANI enable" should not be set automatically on non-native interfaces.</t>
          <t>If
          <t indent="0" pn="section-9.3.4-4">If the tunnel would connect two previously disjoint ACP regions, then it likely would be useful for the ACP.  A Data-Plane data plane tunnel could also run across nodes without ACP and provide additional connectivity for an already connected ACP network.  The benefit of this additional ACP redundancy has to be weighed against the problems of relying on the Data-Plane. data plane.  If a tunnel connects two separate ACP regions: regions, how many tunnels should be created to connect these ACP regions reliably enough? Between which nodes? These are all standard tunneled network design questions not specific to the ACP, and there are no generic generic, fully automated answers.</t>
          <t>Instead
          <t indent="0" pn="section-9.3.4-5">Instead of automatically setting "ACP enable" on these type types of interfaces, the decision needs to be based on the use purpose of the non-native interface interface, and "ACP enable" needs to be set in conjunction with the mechanism through which the non-native interface is created/configured.</t>
          <t>In created and/or configured.</t>
          <t indent="0" pn="section-9.3.4-6">In addition to the explicit setting of "ACP/ANI enable", non-native interfaces also need to support configuration of the ACP RPL cost of the link - to avoid the problems of attracting too much traffic to the link as described above.</t>
          <t>Even
          <t indent="0" pn="section-9.3.4-7">Even native interfaces may not be able to automatically perform BRSKI or ACP because they may require additional operator input to become operational.  Example  Examples include DSL interfaces requiring PPPoE Point-to-Point Protocol over Ethernet (PPPoE) credentials or mobile interfaces requiring credentials from a SIM card.  Whatever mechanism is used to provide the necessary config configuration to the device to enable the interface can also be expanded to decide on whether or not to set "ACP/ANI enable".</t>
          <t>The
          <t indent="0" pn="section-9.3.4-8">The goal of automatically setting "ACP/ANI enable" on interfaces (native or not) is to eliminate unnecessary "touches" to the node to make its operation as much as possible "zero-touch" with respect to ACP/ANI.  If there are "unavoidable touches" such a creating/configuring creating and/or configuring a non-native interface or provisioning credentials for a native interface, then "ACP/ANI enable" should be added as an option to that "touch".  If a wrong an erroneous "touch" is easily fixed (not creating (does not create another high-cost touch), then the default should be not to enable ANI/ACP, and if it is potentially expensive or slow to fix (e.g., parameters on SIM card shipped to remote location), then the default should be to enable ACP/ANI.</t>
        </section>
        <section anchor="node-enable" numbered="true" toc="default">
          <name>Node Level ACP/ANI enable</name>
          <t>A node level toc="include" removeInRFC="false" pn="section-9.3.5">
          <name slugifiedName="name-enabling-node-level-acp-and">Enabling Node-Level ACP and ANI</name>
          <t indent="0" pn="section-9.3.5-1">A node-level command "ACP/ANI enable [up-if-only]" enables ACP or ANI on the node (ANI = ACP + BRSKI).  Without this command set, any interface level interface-level "ACP/ANI enable" is ignored.  Once set, ACP/ANI will operate an interface where "ACP/ANI enable" is set.  Setting of interface level interface-level "ACP/ANI enable" is either automatic (default) or explicit through operator action as described in the previous section.</t>
          <t>If <xref target="if-enable-auto" format="default" sectionFormat="of" derivedContent="Section 9.3.4"/>.</t>
          <t indent="0" pn="section-9.3.5-2">If the option "up-if-only" is selected, the behavior of "down" interfaces is unchanged, and ACP/ANI will only operate on interfaces where "ACP/ANI enable" is set and that are "up".  When it is not set, then "down" state of interfaces with "ACP/ANI enable" is modified to behave as "admin down".</t>
          <section anchor="brownfield" numbered="true" toc="default">
            <name>Brownfield nodes</name>
            <t>A toc="include" removeInRFC="false" pn="section-9.3.5.1">
            <name slugifiedName="name-brownfield-nodes">Brownfield Nodes</name>
            <t indent="0" pn="section-9.3.5.1-1">A "brownfield" node is one that already has a configured Data-Plane.</t>
            <t>Executing data plane.</t>
            <t indent="0" pn="section-9.3.5.1-2">Executing global "ACP/ANI enable [up-if-only]" on each node is the only command necessary to create an ACP across a network of brownfield nodes once all the nodes have a domain certificate.  When BRSKI is used ("ANI enable"), provisioning of the certificates only requires set-up the setup of a single BRSKI registrar node node, which could also implement a CA for the network.  This is the simplest way to introduce ACP/ANI into existing (== (i.e., brownfield) networks.</t>
            <t>The
            <t indent="0" pn="section-9.3.5.1-3">The need to explicitly enable ACP/ANI is especially important in brownfield nodes because otherwise software updates may introduce support for ACP/ANI: Automatic enablement ACP/ANI. The automatic enabling of ACP/ANI in networks where the operator does not only not want ACP/ANI but where the operator or has likely never even heard of it could be quite irritating to the operator.  Especially operator, especially when "down" behavior is changed to "admin down".</t>
            <t>Automatically
            <t indent="0" pn="section-9.3.5.1-4">Automatically setting "ANI enable" on brownfield nodes where the operator is unaware of BRSKI and MASA operations
 could also be an unlikely unlikely, but then critical critical, security issue. If an attacker could impersonate the operator and register by registering
as the operator at the MASA or otherwise get getting hold of vouchers and can could get enough physical access to the network so
pledges would register to an attacking registrar, then the attacker could gain access to the
 ACP, and
 ACP and, through the ACP ACP, gain access to the Data-Plane.</t>

            <t>In data plane.</t>
            <t indent="0" pn="section-9.3.5.1-5">In networks where the operator explicitly wants to enable enables the ANI ANI, this could not happen, happen because the operator would create a BRSKI registrar that would discover attack attempts, and the operator would be setting set up his registrar with the MASA.  Nodes requiring "ownership vouchers" would not be subject to that attack.  See <xref target="I-D.ietf-anima-bootstrapping-keyinfra" format="default"/> target="RFC8995" format="default" sectionFormat="of" derivedContent="RFC8995"/> for more details.  Note that a global "ACP enable" alone is not subject to these type types of attacks, attacks because it they always depends depend on some other mechanism first to provision domain certificates into the device.</t>
          </section>
          <section anchor="greenfield" numbered="true" toc="default">
            <name>Greenfield nodes</name>

            <t>An toc="include" removeInRFC="false" pn="section-9.3.5.2">
            <name slugifiedName="name-greenfield-nodes">Greenfield Nodes</name>
            <t indent="0" pn="section-9.3.5.2-1">An ACP "greenfield" node is one that does not have any prior configuration and that can be bootstrapped into the ACP across the network. To support greenfield nodes, ACP as described in this document needs to be combined with a bootstrap protocol/mechanism protocol and/or mechanism that will enroll the node with the ACP keying material - material: the ACP certificate and the TA. For ANI nodes, this protocol/mechanism is BRSKI.</t>

            <t>When
            <t indent="0" pn="section-9.3.5.2-2">When such a node is powered on and determines that it is in greenfield condition, it enables the bootstrap protocol(s)/mechanism(s), and once protocol(s) and/or mechanism(s). Once the ACP keying material is enrolled, the greenfield state ends and the ACP is started. When BRSKI is used, the node's state reflects this by setting "ANI enable" upon determination of greenfield state at power when it is powered on.</t>

            <t>ACP
            <t indent="0" pn="section-9.3.5.2-3">ACP greenfield nodes that that, in the absence of ACP ACP, would have their interfaces in "down" state SHOULD <bcp14>SHOULD</bcp14> set all native interfaces into "admin down" state and only permit Data-Plane data plane traffic required for the bootstrap protocol/mechanisms.</t>

<t>ACP protocol and/or mechanisms.</t>
            <t indent="0" pn="section-9.3.5.2-4">The ACP greenfield state ends either through the successful enrolment enrollment of ACP keying material (certificate, (certificate and TA) or the detection of a permitted termination of ACP greenfield operations.</t>

            <t>ACP
            <t indent="0" pn="section-9.3.5.2-5">ACP nodes supporting greenfield operations MAY <bcp14>MAY</bcp14> want to provide backward compatibility with other forms of configuration/provisioning, configuration and/or provisioning, especially when only a subset of nodes are expected to be deployed with ACP. Such an ACP node SHOULD <bcp14>SHOULD</bcp14> observe attempts to provision/configure provision or configure the node via interfaces/methods that interfaces and/or methods that traditionally indicate physical possession of the node, such as a serial or USB console port or a USB memory stick with a bootstrap configuration. When such an operation is observed before enrollment of the ACP keying material has completed, the node SHOULD <bcp14>SHOULD</bcp14> put itself into the state the node would have been in, in if ACP/ANI was disabled at boot (terminate boot. This terminates ACP greenfield operations).</t>

            <t>When operations.</t>
            <t indent="0" pn="section-9.3.5.2-6">When an ACP greenfield node enables multiple multiple, automated ACP or non-ACP enrollment/bootstrap protocols/mechanisms enrollment and/or bootstrap protocols or mechanisms in parallel, care must be taken not to terminate any protocol/mechanism before another one has the others either have succeeded to enroll in enrolling ACP keying material or has have progressed to a point where it is of permitted to be a termination reason for ACP greenfield operations.</t>

            <t>Highly
            <t indent="0" pn="section-9.3.5.2-7">Highly secure ACP greenfield nodes may not permit any reason to terminate ACP greenfield operations, including physical access.</t>

            <t>Nodes
            <t indent="0" pn="section-9.3.5.2-8">Nodes that claim to support ANI greenfield operations SHOULD NOT <bcp14>SHOULD NOT</bcp14> enable in parallel to BRSKI any enrollment/bootstrap protocol/mechanism that allows Trust On First Use (TOFU, "<xref target="RFC7435" format="title" sectionFormat="of" derivedContent="Opportunistic Security: Some Protection Most of the Time"/>" <xref target="RFC7435" format="default"/>) format="default" sectionFormat="of" derivedContent="RFC7435"/>) over interfaces other than those traditionally indicating physical possession of the node.  Protocols/mechanisms with published default username/password authentication are considered to suffer from TOFU. Securing the bootstrap protocol/mechanism by requiring a voucher (<xref <xref target="RFC8366" format="default"/>) format="default" sectionFormat="of" derivedContent="RFC8366"/> can be used to avoid TOFU.</t>

            <t>In
            <t indent="0" pn="section-9.3.5.2-9">In summary, the goal of ACP greenfield support is to allow remote remote, automated enrollment of ACP keying materials, and therefore automated bootstrap into the ACP and to prohibit TOFU during bootstrap with the likely exception (for backward compatibility) of bootstrapping via interfaces traditionally indicating physical possession of the node.</t>
          </section>
        </section>
        <section anchor="disabling" numbered="true" toc="default">
          <name>Undoing ANI/ACP enable</name>
          <t>Disabling toc="include" removeInRFC="false" pn="section-9.3.6">
          <name slugifiedName="name-undoing-ani-acp-enable">Undoing "ANI/ACP enable"</name>
          <t indent="0" pn="section-9.3.6-1">Disabling ANI/ACP by undoing "ACP/ANI enable" is a risk for the reliable operations of the ACP if it can be executed by mistake or unauthorized. without authorization.
This behavior could be influenced through some additional (future) property in the certificate (e.g., in the acp-node-name extension field): In in an ANI deployment intended for convenience, disabling it could be allowed without further constraints.  In an ANI deployment considered to be critical critical, more checks would be required.
One very controlled option would be to not permit these commands unless the domain certificate has been revoked or is denied renewal.  Configuring this option would be a parameter on the BRSKI registrar(s).  As long as the node did not receive a domain certificate, undoing "ANI/ACP enable" should not have any additional constraints.</t>
        </section>
        <section anchor="enable-summary" numbered="true" toc="default">
          <name>Summary</name>
          <t>Node-wide toc="include" removeInRFC="false" pn="section-9.3.7">
          <name slugifiedName="name-summary-2">Summary</name>
          <t indent="0" pn="section-9.3.7-1">Node-wide "ACP/ANI enable [up-if-only]" commands enable the operation of ACP/ANI.  This is only auto-enabled on ANI greenfield devices, otherwise it must be configured explicitly.</t>
          <t>If
          <t indent="0" pn="section-9.3.7-2">If the option "up-if-only" is not selected, interfaces enabled for ACP/ANI interpret the "down" state as "admin down" and not "physical down".  In the "admin-down" state, all non-ACP/ANI packets are filtered, but the physical layer is kept running to permit ACP/ANI to operate.</t>
          <t>(New)
          <t indent="0" pn="section-9.3.7-3">(New) commands that result in physical interruption ("physical down", "loopback") of ACP/ANI enabled ACP/ANI-enabled interfaces should be built to protect continuance or reestablishment of ACP as much as possible.</t>
          <t>Interface level
          <t indent="0" pn="section-9.3.7-4">Interface-level "ACP/ANI enable" commands control per-interface operations.  It is enabled by default on native interfaces and has to be configured explicitly on other interfaces.</t>
          <t>Disabling
          <t indent="0" pn="section-9.3.7-5">Disabling "ACP/ANI enable" global globally and per-interface per interface should have additional checks to minimize undesired breakage of ACP.  The degree of control could be a domain wide domain-wide parameter in the domain certificates.</t>
        </section>
      </section>
      <section anchor="incremental-adoption" numbered="true" toc="default">
        <name>Partial toc="include" removeInRFC="false" pn="section-9.4">
        <name slugifiedName="name-partial-or-incremental-adop">Partial or Incremental adoption</name>
        <t>The ACP Adoption</name>
        <t indent="0" pn="section-9.4-1">The Zone Addressing Sub-Scheme (see <xref target="zone-scheme" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 6.11.3"/>) allows incremental
adoption of the ACP in a network where ACP can be deployed on edge areas, but not
across the core that is connecting those edges.</t>
        <t>In
        <t indent="0" pn="section-9.4-2">In such a setup, each edge network, such as a branch or campus of an enterprise network network,
has a disjoined  disjoint ACP to which one or more unique Zone-IDs are assigned: ACP nodes registered for
a specific ACP zone have to receive ACP Zone Addressing Sub-scheme Sub-Scheme addresses, for example example,
by virtue of configuring for each such zone one or more ACP Registrars registrars with that Zone-ID.
All the Registrars registrars for these ACP Zones zones need to get ACP certificates from CAs relying on a
common set of TA TAs and of course the same ACP domain name.</t>
        <t>These
        <t indent="0" pn="section-9.4-3">These ACP zones can first be brought up as separate networks without any connection
between them and/or they can be connected across a non-ACP enabled core network through
various non-autonomic operational practices. For example, each separate ACP Zone zone can have an
edge node that is a layer 3 L3 VPN PE (MPLS or IPv6 layer 3 VPN), L3VPN), where a complete
non-autonomic ACP-Core VPN is created by using the ACP VRFs and exchanging the routes
from those ACP VRFs across the VPNs VPN's non-autonomic routing protocol(s).</t>
        <t>While
        <t indent="0" pn="section-9.4-4">While such a setup is possible with any ACP addressing sub-scheme, the
ACP-Zone
Zone Addressing sub-scheme Sub-Scheme makes it easy to configure and scalable for any
VPN routing protocols because every ACP zone would only need needs to indicate one or more
/64 ACP Zone Addressing zone addressing prefix routes into the ACP-Core VPN as opposed to routes
for every individual ACP node as required in the other ACP addressing schemes.</t>
        <t>Note
        <t indent="0" pn="section-9.4-5">Note that the non-autonomous ACP-Core VPN would require requires additional extensions
to propagate GRASP messages when GRASP discovery is desired across the zones.</t>

<t>For
        <t indent="0" pn="section-9.4-6">For example, one could set up on each Zone zone edge router a remote ACP
tunnel to a GRASP hub. The GRASP hub could be implemented at the application level
and could run in the NOC of the network. It would serve to propagate
GRASP announcements between ACP Zones zones and/or generate GRASP announcements for NOC
services.</t>

        <t>Such
        <t indent="0" pn="section-9.4-7">Such a partial deployment may prove to be sufficient or could evolve to become more
autonomous through future standardized or non-standardized nonstandard enhancements, for example example,
by allowing GRASP messages to be propagated across the layer 3 VPN, L3VPN, leveraging for
example L3VPN Multicast multicast support.</t>
        <t>Finally,
        <t indent="0" pn="section-9.4-8">Finally, these partial deployments can be merged into a single single, contiguous complete
autonomous
ACP that is completely autonomous (given appropriate ACP support across the core) without changes
in the crypto material, cryptographic material because the node's ACP certificates are from a single ACP.</t>
      </section>
      <section anchor="configuration" numbered="true" toc="default">
        <name>Configuration toc="include" removeInRFC="false" pn="section-9.5">
        <name slugifiedName="name-configuration-and-the-acp-s">Configuration and the ACP (summary)</name>
        <t>There (Summary)</name>
        <t indent="0" pn="section-9.5-1">There is no desirable configuration for the ACP. Instead, all parameters that need to be configured in support of the ACP are limitations of the solution, but they are only needed in cases where not all components are made autonomic. Wherever this is necessary, it relies on pre-existing preexisting mechanisms for configuration such as CLI or YANG (<xref target="RFC7950" format="default"/>) data models.</t>
        <t>The models ("<xref target="RFC7950" format="title" sectionFormat="of" derivedContent="The YANG 1.1 Data Modeling Language"/>" <xref target="RFC7950" format="default" sectionFormat="of" derivedContent="RFC7950"/>).</t>
        <t indent="0" pn="section-9.5-2">The most important examples of such configuration include:</t>
        <ul spacing="compact">
          <li>When spacing="normal" bare="false" empty="false" indent="3" pn="section-9.5-3">
          <li pn="section-9.5-3.1">When ACP nodes do not support an autonomic way to receive an ACP certificate, for example example, BRSKI, then such a certificate needs to be configured via some pre-existing preexisting mechanisms outside the scope of this specification. Today, router have routers typically have a variety of mechanisms to do this.</li>
          <li>Certificate
          <li pn="section-9.5-3.2">Certificate maintenance requires PKI functions. Discovery of these functions across the ACP is automated (see <xref target="domcert-maint" format="default"/>), format="default" sectionFormat="of" derivedContent="Section 6.2.5"/>), but their configuration is not.</li>
          <li>When non-ACP capable
          <li pn="section-9.5-3.3">When non-ACP-capable nodes such as pre-existing preexisting NMS need to be physically connected to the ACP, the ACP node to which they attach needs to be configured with ACP-connect ACP connect according to <xref target="ACPconnect" format="default"/>. format="default" sectionFormat="of" derivedContent="Section 8.1"/>. It is also possible to use that single physical connection to connect both to the ACP and the Data-Plane data plane of the network as explained in <xref target="SingleIF" format="default"/>.</li>
          <li>When format="default" sectionFormat="of" derivedContent="Section 8.1.4"/>.</li>
          <li pn="section-9.5-3.4">When devices are not autonomically bootstrapped, explicit configuration to enable the ACP needs to be applied. See <xref target="enabling-acp" format="default"/>.</li>
          <li>When format="default" sectionFormat="of" derivedContent="Section 9.3"/>.</li>
          <li pn="section-9.5-3.5">When the ACP needs to be extended across interfaces other than L2, the ACP as defined in this document cannot autodiscover auto-discover candidate neighbors automatically. Remote neighbors need to be configured, see <xref target="remote-acp-neighbors" format="default"/>.</li> format="default" sectionFormat="of" derivedContent="Section 8.2"/>.</li>
        </ul>
        <t>Once
        <t indent="0" pn="section-9.5-4">Once the ACP is operating, any further configuration for the Data-Plane data plane can be configured done more reliably across the ACP itself because the ACP provides addressing and connectivity (routing) independent of the Data-Plane itself. data plane. For this, the configuration methods simply need to also allow to operate operating across the ACP VRF - VRF, for example, with NETCONF, SSH SSH, or any other method.</t>
        <t>The
        <t indent="0" pn="section-9.5-5">The ACP also provides additional security through its hop-by-hop encryption for any such configuration operations: operations. Some legacy configuration methods (SNMP, (for example, SNMP, TFTP, or HTTP) may not use end-to-end encryption, and most of the end-to-end secured configuration methods still allow for easy easy, passive observation along the path about of the configuration taking place (transport (for example, transport flows, port numbers, and/or IP addresses).</t>
        <t>The
        <t indent="0" pn="section-9.5-6">The ACP can and should equally be used equally as the transport to configure any of the aforementioned non-autonomic components of the ACP, but in that case, the same caution needs to be exercised as with Data-Plane data plane configuration without ACP: the ACP. Misconfiguration may cause the configuring entity to be disconnected from the node it configures - configures, for example example, when incorrectly unconfiguring a remote ACP neighbor through which the configured ACP node is reached.</t>
      </section>
    </section>
    <section anchor="benefit" numbered="true" toc="default">
      <name>Summary: toc="include" removeInRFC="false" pn="section-10">
      <name slugifiedName="name-summary-benefits-informativ">Summary: Benefits (Informative)</name>
      <section anchor="self-healing" numbered="true" toc="default">
        <name>Self-Healing toc="include" removeInRFC="false" pn="section-10.1">
        <name slugifiedName="name-self-healing-properties">Self-Healing Properties</name>
        <t>The
        <t indent="0" pn="section-10.1-1">The ACP is self-healing:</t>
        <ul spacing="compact">
          <li>New spacing="normal" bare="false" empty="false" indent="3" pn="section-10.1-2">
          <li pn="section-10.1-2.1">New neighbors will automatically join the ACP after successful validation and will become reachable using their unique ULA address across the ACP.</li>
          <li>When
          <li pn="section-10.1-2.2">When any changes happen in the topology, the routing protocol used in the ACP will automatically adapt to the changes and will continue to provide reachability to all nodes.</li>
          <li>The
          <li pn="section-10.1-2.3">The ACP tracks the validity of peer certificates and tears down ACP secure channels when a peer certificate has expired. When short-lived certificates with lifetimes in on the order of OCSP/CRL refresh times are used, then this allows for removal of invalid peers (whose certificate was not renewed) at similar speeds as when using OCSP/CRL. The same benefit can be achieved when using CRL/OCSP,  periodically refreshing the revocation information and also tearing down ACP secure channels when the peer's (long-lived) certificate is revoked. There is no requirement against for ACP implementations to require this enhancement though enhancement, though, in order to keep the mandatory implementations simpler.</li>
        </ul>
        <t>The
        <t indent="0" pn="section-10.1-3">The ACP can also sustain network partitions and mergers.  Practically all ACP operations are link local, where a network partition has no impact.  Nodes authenticate each other using the domain certificates to establish the ACP locally.  Addressing inside the ACP remains unchanged, and the routing protocol inside both parts of the ACP will lead to two working (although partitioned) ACPs.</t>
        <t>There
        <t indent="0" pn="section-10.1-4">There are a few central dependencies: A a CRL may not be available during a network partition; partition. This can be addressed by a suitable policy to not immediately disconnect neighbors when no CRL is available can address this issue. available.  Also, an ACP Registrar registrar or Certification Authority CA might not be available during a partition.  This may delay renewal of certificates that are to expire in the future, and it may prevent the enrollment of new nodes during the partition.</t>
        <t>Highly
        <t indent="0" pn="section-10.1-5">Highly resilient ACP designs can be built by using ACP Registrars registrars with embedded sub-CA, sub-CAs, as outlined in <xref target="sub-ca" format="default"/>. format="default" sectionFormat="of" derivedContent="Section 9.2.4"/>. As long as a partition is left with one or more of such ACP Registrars, registrars, it can continue to enroll new candidate ACP nodes as long as the ACP Registrar's registrar's sub-CA certificate does not expire. Because the ACP addressing relies on unique Registrar-IDs, a later re-merge merging of partitions will also not cause problems with ACP addresses assigned during partitioning.</t>
        <t>After
        <t indent="0" pn="section-10.1-6">After a network partition, a re-merge merging will just establish the previous status, status: certificates can be renewed, the CRL is available, and new nodes can be enrolled everywhere.  Since all nodes use the same TA, a re-merge the merging will be smooth.</t>
        <t>Merging
        <t indent="0" pn="section-10.1-7">Merging two networks with different TA TAs requires the ACP nodes to trust the union of TA. TAs.  As long as the routing-subdomain hashes are different, the addressing will not overlap. Accidentally, overlaps Overlaps will only happen accidentally in the unlikely event of a 40-bit hash collision in SHA256 SHA-256 (see <xref target="addressing" format="default"/>). format="default" sectionFormat="of" derivedContent="Section 6.11"/>).
Note that the complete mechanisms to merge networks is out of scope of this specification.</t>
        <t>It
        <t indent="0" pn="section-10.1-8">It is also highly desirable for an implementation of the ACP to be able to run it over interfaces that are administratively down.  If this is not feasible, then it might instead be possible to request explicit operator override upon administrative actions that would administratively bring down an interface across which the ACP is running.  Especially running, especially if bringing down the ACP is known to disconnect the operator from the node.  For example, any such down administrative down action could perform a dependency check to see if the transport connection across which this action is performed is affected by the down action (with default RPL routing used, packet forwarding will be symmetric, so this is actually possible to check).</t>
      </section>
      <!-- self-healing -->
      <section anchor="self-protecting" numbered="true" toc="default">
        <name>Self-Protection toc="include" removeInRFC="false" pn="section-10.2">
        <name slugifiedName="name-self-protection-properties">Self-Protection Properties</name>
        <section anchor="self-protecting-outside" numbered="true" toc="default">
          <name>From the outside</name>
          <t>As toc="include" removeInRFC="false" pn="section-10.2.1">
          <name slugifiedName="name-from-the-outside">From the Outside</name>
          <t indent="0" pn="section-10.2.1-1">As explained in <xref target="self-creation" format="default"/>, format="default" sectionFormat="of" derivedContent="Section 6"/>, the ACP is based on secure channels built between nodes that have mutually authenticated each other with their domain certificates.  The channels themselves are protected using standard encryption technologies such as DTLS or IPsec IPsec, which provide additional authentication during channel establishment, data integrity integrity, and data confidentiality protection of data inside the ACP ACP, and in addition, also provide replay protection.</t>
          <t>Attacker
          <t indent="0" pn="section-10.2.1-2">An attacker will not be able to join the ACP unless they have it has a valid ACP certificate. On-path attackers An on-path attacker without a valid ACP certificate cannot inject packets into the ACP due to ACP secure channels. They can An attacker also not cannot decrypt ACP traffic except if they unless it can crack the encryption. They It can attempt behavioral traffic analysis on the encrypted ACP traffic.</t>
          <t>The
          <t indent="0" pn="section-10.2.1-3">The degree to which compromised ACP nodes can impact the ACP depends on the implementation of the ACP nodes and their impairment. When an attacker has only gained administrative privileges to configure ACP nodes remotely, the attacker can disrupt the ACP only through one of the few configuration options to disable it, see it (see <xref target="enabling-acp" format="default"/>, format="default" sectionFormat="of" derivedContent="Section 9.3"/>) or by the configuring of non-autonomic ACP options if those are supported on the impaired ACP nodes, see nodes (see <xref target="workarounds" format="default"/>. format="default" sectionFormat="of" derivedContent="Section 8"/>). Injecting traffic into or extracting traffic into/from from an impaired ACP node is only possible when an impaired ACP node supports ACP connect (see <xref target="ACPconnect" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 8.1"/>), and the attacker can control traffic into/from one of the ACP nodes node's interfaces, such as by having physical access to the ACP node.</t>
          <t>The
          <t indent="0" pn="section-10.2.1-4">The ACP also serves as protection (through authentication and encryption) for protocols relevant to OAM that may not have secured protocol stack options or where implementation or deployment of those options fail on due to some vendor/product/customer vendor, product, or customer limitations.  This includes protocols such as SNMP (<xref ("<xref target="RFC3411" format="title" sectionFormat="of" derivedContent="An Architecture for Describing Simple Network Management Protocol (SNMP) Management Frameworks"/>" <xref target="RFC3411" format="default"/>), format="default" sectionFormat="of" derivedContent="RFC3411"/>), NTP (<xref <xref target="RFC5905" format="default"/>), format="default" sectionFormat="of" derivedContent="RFC5905"/>, PTP (<xref (Precision Time Protocol <xref target="IEEE-1588-2008" format="default"/>), format="default" sectionFormat="of" derivedContent="IEEE-1588-2008"/>), DNS (<xref ("<xref target="RFC3596" format="default"/>), format="title" sectionFormat="of" derivedContent="DNS Extensions to Support IP Version 6"/>" <xref target="RFC3596" format="default" sectionFormat="of" derivedContent="RFC3596"/>), DHCPv6 (<xref ("<xref target="RFC3315" format="default"/>), format="title" sectionFormat="of" derivedContent="Dynamic Host Configuration Protocol for IPv6 (DHCPv6)"/>" <xref target="RFC3315" format="default" sectionFormat="of" derivedContent="RFC3315"/>), syslog (<xref ("<xref target="RFC3164" format="default"/>), format="title" sectionFormat="of" derivedContent="The BSD Syslog Protocol"/>" <xref target="RFC3164" format="default" sectionFormat="of" derivedContent="RFC3164"/>), RADIUS (<xref ("<xref target="RFC2865" format="title" sectionFormat="of" derivedContent="Remote Authentication Dial In User Service (RADIUS)"/>" <xref target="RFC2865" format="default"/>), format="default" sectionFormat="of" derivedContent="RFC2865"/>), Diameter (<xref ("<xref target="RFC6733" format="title" sectionFormat="of" derivedContent="Diameter Base Protocol"/>" <xref target="RFC6733" format="default"/>), format="default" sectionFormat="of" derivedContent="RFC6733"/>), TACACS (<xref ("<xref target="RFC1492" format="title" sectionFormat="of" derivedContent="An Access Control Protocol, Sometimes Called TACACS"/>" <xref target="RFC1492" format="default"/>), format="default" sectionFormat="of" derivedContent="RFC1492"/>), IPFIX (<xref ("<xref target="RFC7011" format="default"/>), Netflow (<xref format="title" sectionFormat="of" derivedContent="Specification of the IP Flow Information Export (IPFIX) Protocol for the Exchange of Flow Information"/>" <xref target="RFC7011" format="default" sectionFormat="of" derivedContent="RFC7011"/>), NetFlow ("<xref target="RFC3954" format="default"/>) - format="title" sectionFormat="of" derivedContent="Cisco Systems NetFlow Services Export Version 9"/>" <xref target="RFC3954" format="default" sectionFormat="of" derivedContent="RFC3954"/>) -- just to name a few. Not all of these protocol references are necessarily the latest version of protocols protocols, but they are versions that are still widely deployed.</t>
          <t>Protection
          <t indent="0" pn="section-10.2.1-5">Protection via the ACP secure hop-by-hop channels for these protocols is meant to be only a stopgap stopgap, though: The the ultimate goal is for these and other protocols to use end-to-end encryption utilizing the domain certificate and to rely on the ACP secure channels primarily for zero-touch reliable connectivity, but not primarily for security.</t>
          <t>The
          <t indent="0" pn="section-10.2.1-6">The remaining attack vector would be to attack the underlying ACP protocols themselves, either via directed attacks or by denial-of-service attacks.  However, as the ACP is built using link-local IPv6 addresses, remote attacks from the Data-Plane data plane are impossible as long as the Data-Plane data plane has no facilities to remotely send IPv6 link-local packets.  The only exceptions are ACP connected interfaces ACP-connected interfaces, which require higher greater physical protection.  The ULA addresses are only reachable inside the ACP context, therefore, context and therefore unreachable from the Data-Plane. data plane.  Also, the ACP protocols should be implemented to be attack resistant and to not consume unnecessary resources even while under attack.</t>
        </section>
        <section anchor="self-protecting-inside" numbered="true" toc="default">
          <name>From the inside</name>
          <t>The toc="include" removeInRFC="false" pn="section-10.2.2">
          <name slugifiedName="name-from-the-inside">From the Inside</name>
          <t indent="0" pn="section-10.2.2-1">The security model of the ACP is based on trusting all members of the group of nodes
 that receive an ACP certificate for the same domain.  Attacks from the inside by
a compromised group member are therefore the biggest challenge.</t>
          <t>Group
          <t indent="0" pn="section-10.2.2-2">Group members must be protected against attackers so that there is no easy way to compromise them, them
or use them as a proxy for attacking other devices across the ACP. For example, management plane
functions (transport ports) should only be reachable only from the ACP but and not from the Data-Plane.
Especially for data plane.
This applies especially to those management plane functions that have no good protection by themselves because they
do not have lack
secure end-to-end transport and to whom which the ACP not only provides automatic both automatic, reliable
 connectivity but also and protection against attacks.  Protection across all potential
attack vectors is typically easier to do in devices whose software is designed from the ground up beginning with
the ACP in mind than with legacy software based in legacy, software-based systems where the ACP is added on as another feature.</t>
          <t>As
          <t indent="0" pn="section-10.2.2-3">As explained above, traffic across the ACP should still be end-to-end encrypted whenever
possible.  This includes traffic such as GRASP, EST EST, and BRSKI inside the ACP.  This minimizes
man in the middle
man-in-the-middle attacks by compromised ACP group members.  Such attackers cannot eavesdrop
or modify communications, but they can just filter them (which is unavoidable by any means).</t>
          <t>See
          <t indent="0" pn="section-10.2.2-4">See <xref target="compromised" format="default"/> format="default" sectionFormat="of" derivedContent="Appendix A.9.8"/> for further considerations how to avoid on avoiding and deal dealing with
compromised nodes.</t>
        </section>
      </section>
      <!-- self-protecting -->
      <section anchor="admin-view" numbered="true" toc="default">
        <name>The toc="include" removeInRFC="false" pn="section-10.3">
        <name slugifiedName="name-the-administrator-view">The Administrator View</name>
        <t>An
        <t indent="0" pn="section-10.3-1">An ACP is self-forming, self-managing self-managing, and self-protecting, therefore self-protecting; therefore, it has minimal dependencies on the administrator of the network.  Specifically, since it is (intended to be) independent of configuration, there is only limited scope for configuration errors on the ACP itself.  The administrator may have the option to enable or disable the entire approach, but detailed configuration is not possible.  This means that the ACP must not be reflected in the running configuration of nodes, except for a possible on/off switch (and even that is undesirable).</t>
        <t>While
        <t indent="0" pn="section-10.3-2">While configuration (except for <xref target="workarounds" format="default"/> format="default" sectionFormat="of" derivedContent="Section 8"/> and  <xref target="registrar-considerations" format="default"/>) format="default" sectionFormat="of" derivedContent="Section 9.2"/>)
 is not possible, an administrator must have full visibility of into the ACP and all its parameters, parameters to be able to do trouble-shooting. troubleshoot.  Therefore, an ACP must support all show and debug options, as for with any other network function.  Specifically, a network management system an NMS or controller must be able to discover the ACP, ACP and monitor its health.  This visibility of into ACP operations must clearly be separated from the visibility of Data-Plane the data plane so automated systems will never have to deal with ACP aspects unless they explicitly desire to do so.</t>
        <t>Since
        <t indent="0" pn="section-10.3-3">Since an ACP is self-protecting, a node that does not supporting support the ACP, ACP or without a valid domain that does not have a valid domain certificate cannot connect to it.  This means that by default a traditional controller or network management system NMS cannot connect to an ACP.  See <xref target="NMS" format="default"/> format="default" sectionFormat="of" derivedContent="Section 8.1.1"/> for more details on how to connect an NMS host into to the ACP.</t>
      </section>
      <!-- admin-view -->
    </section>
    <!-- benefits -->
    <section anchor="security" numbered="true" toc="default">
      <name>Security toc="include" removeInRFC="false" pn="section-11">
      <name slugifiedName="name-security-considerations">Security Considerations</name>
      <t>A
      <t indent="0" pn="section-11-1">A set of ACP nodes with ACP certificates for the same ACP domain and with ACP functionality enabled is automatically "self-building": The the ACP is automatically established between neighboring ACP nodes. It is also "self-protecting": The self-protecting: the ACP secure channels are authenticated and encrypted. No configuration is required for this.</t>
      <t>The
      <t indent="0" pn="section-11-2">The self-protecting property does not include workarounds for non-autonomic components as explained in <xref target="workarounds" format="default"/>. format="default" sectionFormat="of" derivedContent="Section 8"/>. See <xref target="self-protecting" format="default"/> format="default" sectionFormat="of" derivedContent="Section 10.2"/> for details of how the ACP protects itself against attacks from the outside and and, to a more limited degree degree, from the inside as well.</t>
      <t>However,
      <t indent="0" pn="section-11-3">However, the security of the ACP depends on a number of other factors:
      </t>
      <ul spacing="compact">
        <li>The spacing="normal" bare="false" empty="false" indent="3" pn="section-11-4">
        <li pn="section-11-4.1">The usage of domain certificates depends on a valid supporting PKI infrastructure.  If the chain of trust of this PKI infrastructure is compromised, the security of the ACP is also compromised.  This is typically under the control of the network administrator.</li>
        <li>ACP
        <li pn="section-11-4.2">ACP nodes receive their certificates from ACP registrars. These ACP registrars are security critical security-critical dependencies of the ACP: ACP.  Procedures and protocols for ACP registrars are outside the scope of this specification as explained in <xref target="registrars-protocols" format="default"/>, format="default" sectionFormat="of" derivedContent="Section 6.11.7.1"/>; only the requirements against for the resulting ACP certificates are specified.</li>

        <li>Every
        <li pn="section-11-4.3">Every ACP registrar (for enrollment of ACP certificates) and ACP EST server (for renewal of ACP certificates) is a security critical security-critical entity and its protocols are security critical security-critical protocols. Both need to be hardened against attacks, similar to a CA and its protocols. A malicious registrar can enroll malicious nodes to an ACP network (if the CA delegates this policy to the registrar) or break ACP routing routing, for example example, by assigning duplicate ACP address assignment addresses to ACP nodes via their ACP certificates.</li>

        <li>ACP
        <li pn="section-11-4.4">ACP nodes that are ANI nodes rely on BRSKI as the protocol for ACP registrars. For ANI type ANI-type ACP nodes, the security considerations of BRSKI apply. It enables automated, secure enrollment of ACP certificates.</li>

        <li>BRSKI
        <li pn="section-11-4.5">BRSKI and potentially other ACP registrar protocol options require that nodes have an (X.509v3 (X.509 v3 based) IDevID. IDevIDs are an option for ACP registrars to securely identify candidate ACP nodes that should be enrolled into an ACP domain.</li>

        <li>For
        <li pn="section-11-4.6">For IDevIDs to securely identify the node to which it its IDevID is assigned, the node needs to (1) to utilize hardware support such as a Trusted Platform Module (TPM) to protect against extraction/cloning extraction and/or cloning of the private key of the IDevID and (2) a hardware/software infrastructure to prohibit execution of non-authenticated unauthenticated software to protect against malicious use of the IDevID.</li>

        <li>Like
        <li pn="section-11-4.7">Like the IDevID, the ACP certificate should equally be protected from extraction or other abuse by the same ACP node infrastructure. This infrastructure for IDevID and ACP certificate is beneficial independent of the ACP registrar protocol used (BRSKI or other).</li>

        <li>Renewal
        <li pn="section-11-4.8">Renewal of ACP certificates requires support for EST, therefore EST; therefore, the security considerations of <xref target="RFC7030" format="default"/> format="default" sectionFormat="of" derivedContent="RFC7030"/> related to certificate renewal/rekeying renewal and/or rekeying and TP renewal apply to the ACP. EST security considerations when using other than mutual certificate authentication do not apply apply, nor do considerations for initial enrollment via EST apply, except for ANI type ANI-type ACP nodes because BRSKI leverages EST.</li>

        <li>A
        <li pn="section-11-4.9">A malicious ACP node could declare itself to be an EST server via GRASP across the ACP if malicious software could be executed on it. The CA should therefore authenticate only known trustworthy EST servers, such as nodes with hardware protections against malicious software. When Registrars registrars use their ACP certificate to authenticate towards a CA, the id-kp-cmcRA <xref target="RFC6402" format="default"/> format="default" sectionFormat="of" derivedContent="RFC6402"/> extended key usage attribute allows the CA to determine that the ACP node was permitted during enrollment to act as an ACP registrar.  Without the ability to talk to the CA, a malicious EST server can still attract ACP nodes attempting to renew their keying material, but they will fail to perform successful renewal of a valid ACP certificate. The ACP node attempting to use the malicious EST server can then continue to use a different EST server, server and log a failure against a malicious EST server.</li>

        <li>Malicious
        <li pn="section-11-4.10">Malicious on-path ACP nodes may filter valid EST server announcements across the ACP, but such malicious ACP nodes could equally filter any ACP traffic such as the EST traffic itself. Either attack requires the ability to execute malicious software on an impaired ACP node node, though.</li>

        <li>In
        <li pn="section-11-4.11">In the absence of malicious software injection, an attacker that can misconfigure an ACP node which is supporting that supports EST server functionality could attempt to configure a malicious CA. This would not result in the ability to successfully renew ACP certificates, but it could result in DoS attacks by becoming an EST server and by making ACP nodes attempting attempt their ACP certificate renewal via this impaired ACP node. This problem can be avoided when the EST server implementation can verify that the CA configured CA is indeed providing renewal for certificates of the node's ACP. The ability to do so depends on the EST-Server to CA protocol, protocol between the EST server and the CA, which is outside the scope of this document.</li>
      </ul>

<t>In
      <t indent="0" pn="section-11-5">In summary, attacks against the PKI/certificate dependencies of the ACP can be minimized by a variety of hardware/software components hardware and/or software components, including options such as TPM for IDevID/ACP-certificate, IDevID and/or ACP certificate, prohibitions against the execution of non-trusted software untrusted software, and design aspects of the EST Server server functionality for the ACP to that eliminate configuration level configuration-level impairment.</t>

      <t>Because
      <t indent="0" pn="section-11-6">Because ACP peers select one out of potentially more than one mutually supported ACP secure channel protocols via the approach described in <xref target="channel-selection"/>, target="channel-selection" format="default" sectionFormat="of" derivedContent="Section 6.6"/>, ACP secure channel setup is subject to downgrade attacks by MITM attackers. This can be discovered after such an attack by additional mechanisms described in <xref target="downgrade"/>. target="downgrade" format="default" sectionFormat="of" derivedContent="Appendix A.9.9"/>. Alternatively, more advanced channel selection mechanisms can be devised. [RFC-Editor: Please remove the following sentence]. See <xref target="ACPDRAFT"/> Appendix B.1. Both options are out of scope of this document.</t>

<t>The devised.</t>
      <t indent="0" pn="section-11-7">The security model of the ACP as defined in this document is tailored for use with private PKI. The TA of a private PKI provide provides the security against maliciously created ACP certificates to that give access to an ACP. Such attacks can create fake ACP certificates with correct looking correct-looking AcpNodeNames, but those certificates would not pass the certificate path validation of the ACP domain membership check (see <xref target="certcheck"/>, target="certcheck" format="default" sectionFormat="of" derivedContent="Section 6.2.3"/>, point 2).</t>

<t>[RFC-Editor: please remove the following paragraph].</t>
<t>Using public CA is out of scope of this document. See <xref target="ACPDRAFT"/>, Appendix B.3 for further considerations.</t>

      <t>There
      <t indent="0" pn="section-11-8">There is no prevention of source-address spoofing inside the ACP.  This implies that if an attacker gains access to the ACP, it can spoof all addresses inside the ACP and fake messages from any other node. New protocol/services run protocols and/or services running across the ACP should therefore use end-to-end authentication inside the ACP. This is already done by GRASP as specified in this document.</t>

      <t>The
      <t indent="0" pn="section-11-9">The ACP is designed to enable automation of current network management and the management of future autonomic peer-to-peer/distributed network automation. networks. Any ACP member can send ACP IPv6 packet packets to other ACP members and announce via ACP GRASP services to all ACP members without dependency against depending on centralized components.</t>

      <t>The
      <t indent="0" pn="section-11-10">The ACP relies on peer-to-peer authentication and authorization using ACP certificates.  This security model is necessary to enable the autonomic ad-hoc ad hoc, any-to-any connectivity between ACP nodes. It provides infrastructure protection through hop by hop hop-by-hop authentication and encryption - -- without relying on third parties. For any services where this complete autonomic peer-to-peer group security model is appropriate, the ACP certificate can also be used unchanged. For unchanged, for example, for any type of Data-Plane data plane routing protocol security.</t>

      <t>This
      <t indent="0" pn="section-11-11">This ACP security model is designed primarily to protect against attack from the outside, but not against attacks from the inside.  To protect against spoofing attacks from compromised on-path ACP nodes, end-to-end encryption inside the ACP is used by new ACP signaling: GRASP across the ACP using TLS. The same is expected from any non-legacy services/protocols services or protocols using the ACP. Because no group-keys group keys are used, there is no risk for of impacted nodes to access accessing end-to-end encrypted traffic from other ACP nodes.</t>

      <t>Attacks
      <t indent="0" pn="section-11-12">Attacks from impacted ACP nodes against the ACP are more difficult than against the Data-Plane data plane because of the autoconfiguration of the ACP and the absence of configuration options that could be abused that allow to change/break change or break ACP behavior. This is excluding configuration for workaround in support of non-autonomic components.</t>

      <t>Mitigation
      <t indent="0" pn="section-11-13">Mitigation against compromised ACP members is possible through standard automated certificate management mechanisms including revocation and non-renewal nonrenewal of short-lived certificates. In this version of the specification, there are no further optimization optimizations of these mechanisms defined for the ACP (but see <xref target="compromised" format="default"/>).</t>

      <t>Higher layer format="default" sectionFormat="of" derivedContent="Appendix A.9.8"/>).</t>
      <t indent="0" pn="section-11-14">Higher-layer service built using ACP certificates should not solely rely on undifferentiated group security when another model is more appropriate/more appropriate or more secure. For example, central network configuration relies on a security model where only a few especially trusted nodes are allowed to configure the Data-Plane data plane of network nodes (CLI, NETCONF). This can be done through ACP certificates by differentiating them and introduce introducing roles. See <xref target="role-assignments" format="default"/>.</t>
      <!--

                        <t>Fundamentally, security depends on avoiding operator and network operations automation mistakes, implementation and architecture.  Autonomic approaches such as the ACP largely eliminate operator mistakes and make it easier to recover from network operations mistakes. Implementation and architectural mistakes are still possible, as in all networking technologies.</t>

-->
      <t>Operators format="default" sectionFormat="of" derivedContent="Appendix A.9.5"/>.</t>
      <t indent="0" pn="section-11-15">Operators and developers of provisioning software developers need to be aware of how the provisioning/configuration provisioning and configuration of network devices impacts the ability of the operator / and/or provisioning software to remotely access the network nodes. By using the ACP, most of the issues of configuration/provisioning caused provisioning/configuration causing connectivity loss of connectivity for remote provisioning/configuration provisioning and configuration will be eliminated, see <xref target="self-creation" format="default"/>. format="default" sectionFormat="of" derivedContent="Section 6"/>. Only a few exceptions exceptions, such as explicit physical interface down configuration configuration, will be left left. See <xref target="admin-down" format="default"/>.</t>

      <t>Many format="default" sectionFormat="of" derivedContent="Section 9.3.2"/>.</t>
      <t indent="0" pn="section-11-16">Many details of ACP are designed with security in mind and discussed elsewhere in the document:</t>
      <t>IPv6 document.</t>
      <t indent="0" pn="section-11-17">IPv6 addresses used by nodes in the ACP are covered as part of the node's domain certificate as described in <xref target="domcert-acpinfo" format="default"/>. format="default" sectionFormat="of" derivedContent="Section 6.2.2"/>.  This allows even verification of ownership of a peer's IPv6 address when using a connection authenticated with the domain certificate.</t>
      <t>The
      <t indent="0" pn="section-11-18">The ACP acts as a security (and transport) substrate for GRASP inside the ACP such that GRASP is not only protected by attacks from the outside, but also by attacks from compromised inside attackers - -- by relying not only on hop-by-hop security of ACP secure channels, but also by adding end-to-end security for those GRASP messages.  See <xref target="GRASP-substrate" format="default"/>.</t>
      <t>ACP format="default" sectionFormat="of" derivedContent="Section 6.9.2"/>.</t>
      <t indent="0" pn="section-11-19">ACP provides for secure, resilient zero-touch discovery of EST servers for certificate renewal.  See <xref target="domcert-maint" format="default"/>.</t>
      <t>ACP format="default" sectionFormat="of" derivedContent="Section 6.2.5"/>.</t>
      <t indent="0" pn="section-11-20">ACP provides extensible, auto-configuring autoconfiguring hop-by-hop protection of the ACP infrastructure via the negotiation of hop-by-hop secure channel protocols.  See <xref target="channel-selection" format="default"/>.</t>

      <t>The format="default" sectionFormat="of" derivedContent="Section 6.6"/>.</t>
      <t indent="0" pn="section-11-21">The ACP is designed to minimize attacks from the outside by minimizing its dependency against on any non-ACP (Data-Plane) operations/configuration (data plane) operations and/or configuration on a node.  See also <xref target="general_addressing" format="default"/>.</t>

      <t>In format="default" sectionFormat="of" derivedContent="Section 6.13.2"/>.</t>
      <t indent="0" pn="section-11-22">In combination with BRSKI, ACP enables a resilient, fully zero-touch network solution for short-lived certificates that can be renewed or re-enrolled reenrolled even after unintentional expiry (e.g., because of due to interrupted connectivity).  See <xref target="bootstrap" format="default"/>.</t>

      <t>Because format="default" sectionFormat="of" derivedContent="Appendix A.2"/>.</t>
      <t indent="0" pn="section-11-23">Because ACP secure channels can be long lived, but certificates used may be short lived, short-lived, secure channels, for example example, built via IPsec IPsec, need to be terminated when peer certificates expire. See <xref target="Profiles" format="default"/>.</t>

      <t><xref format="default" sectionFormat="of" derivedContent="Section 6.8.5"/>.</t>
      <t indent="0" pn="section-11-24"><xref target="acp-l2-switches-how" format="default"/> format="default" sectionFormat="of" derivedContent="Section 7.2"/> describes how to implement a routed
ACP topology operating on what effectively is a large bridge-domain bridge domain when using
L3/L2 routers that operate at L2 in the Data-Plane. data plane. In this case, the ACP is
subject to a much higher likelihood of attacks by other nodes "stealing"
L2 addresses than in the actual routed case. Especially case, especially when the bridged network
includes non-trusted untrusted devices such as hosts.  This is a generic issue in L2 LANs.
L2/L3 devices often already have some form of "port security" to prohibit this.  They rely on
NDP
Neighbor Discovery Protocol (NDP) or DHCP learning of which port/MAC-address and IPv6 address belong together and block blocking
MAC/IPv6 source addresses from wrong ports.  This type of function needs to be
enabled to prohibit DoS attacks and specifically to protect the ACP.  Likewise  Likewise, the
GRASP DULL instance needs to ensure that the IPv6 address in the locator-option matches the source IPv6 address of the DULL GRASP packet.</t>
    </section>
    <!-- security -->
    <section anchor="iana" numbered="true" toc="default">
      <name>IANA toc="include" removeInRFC="false" pn="section-12">
      <name slugifiedName="name-iana-considerations">IANA Considerations</name>
      <t>This
      <t indent="0" pn="section-12-1">This document defines the "Autonomic Control Plane".</t>
      <t>For
      <t indent="0" pn="section-12-2">For the ANIMA-ACP-2020 ASN.1 module, IANA is asked to register has assigned
value IANA1 97 for "id-mod-anima-acpnodename-2020" in the "SMI
Security for PKIX Module Identifier" (1.3.6.1.5.5.7.0) registry.</t>
      <t>For
      <t indent="0" pn="section-12-3">For the otherName / AcpNodeName, IANA is asked to register a has assigned value for IANA2 10 for
id-on-AcpNodeName in the "SMI Security for PKIX Other Name
Forms" (1.3.6.1.5.5.7.8) registry.</t>
      <t> The IANA is requested to register the value "AN_ACP" (without quotes)
to
      <t indent="0" pn="section-12-4">IANA has registered the GRASP Objectives Names Table names in the GRASP Parameter Registry.  The
specification for this value is this document, <xref target="discovery-grasp" format="default"/>.</t>
      <t> The IANA is requested to register the value "SRV.est" (without quotes)
to the GRASP Objectives Names Table target="iana-objnames" format="default" sectionFormat="of" derivedContent="Table 2"/> in
the GRASP Parameter Registry.  The
specification for this value is this document, <xref "GRASP Objective Names" subregistry of the "GeneRic Autonomic Signaling Protocol (GRASP) Parameters" registry.</t>
      <table anchor="iana-objnames" align="center" pn="table-2">
        <name slugifiedName="name-grasp-objective-names">GRASP Objective Names</name>
        <thead>
          <tr>
            <th align="left" colspan="1" rowspan="1">Objective Name</th>
            <th align="left" colspan="1" rowspan="1">Reference</th>
          </tr>
        </thead>
        <tbody>
          <tr>
            <td align="left" colspan="1" rowspan="1">AN_ACP</td>
            <td align="left" colspan="1" rowspan="1">RFC 8994 (<xref target="discovery-grasp" format="default" sectionFormat="of" derivedContent="Section 6.4"/>)</td>
          </tr>
          <tr>
            <td align="left" colspan="1" rowspan="1">SRV.est</td>
            <td align="left" colspan="1" rowspan="1">RFC 8994 (<xref target="domcert-maint" format="default"/>.</t>
      <t>Explanation: This format="default" sectionFormat="of" derivedContent="Section 6.2.5"/>)</td>
          </tr>
        </tbody>
      </table>
      <t indent="0" pn="section-12-6">Explanation: this document chooses the initially strange looking format "SRV.&lt;service-name&gt;" because these objective names would be in line with potential future simplification of the GRASP objective registry. Today, every name in the GRASP objective registry needs to be explicitly allocated with by IANA. In the future, this type of objective names could be considered to be automatically registered in that registry for the same service for which a &lt;service-nameh&gt; &lt;service-name&gt; is registered according to <xref target="RFC6335" format="default"/>. format="default" sectionFormat="of" derivedContent="RFC6335"/>. This explanation is solely informational and has no impact on the requested registration.</t>
      <t> The IANA is requested to create
      <t indent="0" pn="section-12-7">IANA has created an ACP Parameter Registry with
currently one "Autonomic Control Plane (ACP)" registry table - with
the subregistry, "ACP Address Type" table.</t>
      <t>"ACP (<xref target="iana-acpaddresstype" format="default" sectionFormat="of" derivedContent="Table 3"/>).</t>
      <table anchor="iana-acpaddresstype" align="center" pn="table-3">
        <name slugifiedName="name-initial-values-in-the-acp-a">Initial Values in the "ACP Address Type" Table.  The value Subregistry</name>
        <thead>
          <tr>
            <th align="left" colspan="1" rowspan="1">Value</th>
            <th align="left" colspan="1" rowspan="1">Description</th>
            <th align="left" colspan="1" rowspan="1">Reference</th>
          </tr>
        </thead>
        <tbody>
          <tr>
            <td align="left" colspan="1" rowspan="1">0</td>
            <td align="left" colspan="1" rowspan="1">ACP Zone Addressing Sub-Scheme/ACP Manual Addressing Sub-Scheme</td>
            <td align="left" colspan="1" rowspan="1">RFC 8994 (<xref target="zone-scheme" format="default" sectionFormat="of" derivedContent="Section 6.11.3"/>, <xref target="manual-scheme" format="default" sectionFormat="of" derivedContent="Section 6.11.4"/>)</td>
          </tr>
          <tr>
            <td align="left" colspan="1" rowspan="1">1</td>
            <td align="left" colspan="1" rowspan="1">ACP Vlong Addressing Sub-Scheme</td>
            <td align="left" colspan="1" rowspan="1">RFC 8994 (<xref target="Vlong" format="default" sectionFormat="of" derivedContent="Section 6.11.5"/>)</td>
          </tr>
          <tr>
            <td align="left" colspan="1" rowspan="1">2-3</td>
            <td align="left" colspan="1" rowspan="1">Unassigned</td>
            <td align="left" colspan="1" rowspan="1"/>
          </tr>
        </tbody>
      </table>
      <t indent="0" pn="section-12-9">The values in this table the "ACP Address Type" subregistry are numeric values 0...3 0..3 paired with a name (string).  Future values MUST <bcp14>MUST</bcp14> be assigned using the Standards Action policy defined by <xref "<xref target="RFC8126" format="default"/>.  The following initial values are assigned by this document:</t>
      <t>
0: ACP Zone Addressing Sub-Scheme (ACP RFC  <xref target="zone-scheme" format="default"/>)
</t>
<t>
1: ACP Vlong Addressing Sub-Scheme (ACP RFC <xref target="Vlong" format="default"/>) / ACP Manual Addressing Sub-Scheme (ACP RFC <xref target="manual-scheme" format="default"/>)
</t>
    </section>
    <!-- iana -->
    <section anchor="ack" numbered="true" toc="default">
      <name>Acknowledgements</name>
      <t>This work originated from format="title" sectionFormat="of" derivedContent="Guidelines for Writing an Autonomic Networking project at Cisco Systems, which started IANA Considerations Section in early 2010.  Many people contributed to this project RFCs"/>" <xref target="RFC8126" format="default" sectionFormat="of" derivedContent="RFC8126"/>.</t>
    </section>
  </middle>
  <back>
    <displayreference target="I-D.ietf-tls-dtls13" to="TLS-DTLS13"/>
    <displayreference target="I-D.eckert-anima-noc-autoconfig" to="NOC-AUTOCONFIG"/>
    <displayreference target="I-D.ietf-roll-applicability-template" to="ROLL-APPLICABILITY"/>
    <references pn="section-13">
      <name slugifiedName="name-references">References</name>
      <references pn="section-13.1">
        <name slugifiedName="name-normative-references">Normative References</name>
        <reference anchor="IKEV2IANA" target="https://www.iana.org/assignments/ikev2-parameters" quoteTitle="true" derivedAnchor="IKEV2IANA">
          <front>
            <title>Internet Key Exchange Version 2 (IKEv2) Parameters</title>
            <author fullname="IANA">
              <organization showOnFrontPage="true"/>
            </author>
            <date/>
          </front>
        </reference>
        <reference anchor="RFC1034" target="https://www.rfc-editor.org/info/rfc1034" quoteTitle="true" derivedAnchor="RFC1034">
          <front>
            <title>Domain names - concepts and facilities</title>
            <author initials="P.V." surname="Mockapetris" fullname="P.V. Mockapetris">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="1987" month="November"/>
            <abstract>
              <t indent="0">This RFC is the idea revised basic definition of The Domain Name System.  It obsoletes RFC-882.  This memo describes the Autonomic Control Plane, amongst which (in alphabetical order): Ignas Bagdonas, Parag Bhide, Balaji BL, Alex Clemm, Yves Hertoghs, Bruno Klauser, Max Pritikin, Michael Richardson, Ravi Kumar Vadapalli.</t>
      <t>Special thanks to Brian Carpenter, Elwyn Davies, Joel Halpern and Sheng Jiang for their thorough reviews.</t>
      <t>Many thanks Ben Kaduk, Roman Danyliv and Eric Rescorla for their thorough SEC AD reviews, Russ Housley domain style names and Erik Kline for their reviews and to Valery Smyslov, Tero Kivinen, Paul Wouters and Yoav Nir used for review of IPsec host address look up and IKEv2 parameters electronic mail forwarding.  It discusses the clients and helping to understand those servers in the domain name system and other security the protocol details better. Thanks for Carsten Borman used between them.</t>
            </abstract>
          </front>
          <seriesInfo name="STD" value="13"/>
          <seriesInfo name="RFC" value="1034"/>
          <seriesInfo name="DOI" value="10.17487/RFC1034"/>
        </reference>
        <reference anchor="RFC2119" target="https://www.rfc-editor.org/info/rfc2119" quoteTitle="true" derivedAnchor="RFC2119">
          <front>
            <title>Key words for CBOR/CDDL help.</t>
      <t>Further input, review or suggestions were received from: Rene Struik, Benoit Claise, William Atwood and Yongkang Zhang.</t>
    </section>
    <!-- ack -->

    <section anchor="contributors" numbered="true" toc="default">
      <name>Contributors</name>

        <t>For all things GRASP including validation code, ongoing document text support and technical input.</t>

        <contact fullname="Brian Carpenter" initials="B. E." surname="Carpenter">
          <organization abbrev="Univ. of Auckland"/>
          <address>
            <postal>
              <street>School of Computer Science</street>
              <street>University of Auckland</street>
              <street>PB 92019</street>
              <city>Auckland</city>
              <region/>
              <code>1142</code>
              <country>New Zealand</country>
            </postal>
            <email>brian.e.carpenter@gmail.com</email>
          </address>
        </contact>

        <t>For RPL contributions and all things BRSKI/bootstrap including validation code, ongoing document text support and technical input.</t>

    <contact fullname="Michael C. Richardson" initials="M." surname="Richardson">
      <organization abbrev="Sandelman">Sandelman Software Works</organization>
      <address>
        <email>mcr+ietf@sandelman.ca</email>
        <uri>http://www.sandelman.ca/mcr/</uri>
      </address>
    </contact>

        <t>For the RPL technology choices and text.</t>

   <contact initials="P" surname="Thubert" fullname="Pascal Thubert"> use in RFCs to Indicate Requirement Levels</title>
            <author initials="S." surname="Bradner" fullname="S. Bradner">
              <organization abbrev="Cisco Systems">Cisco Systems, Inc</organization>
      <address>
         <postal>
            <street>Building D</street>
            <street>45 Allee des Ormes - BP1200 </street>
            <city>MOUGINS - Sophia Antipolis</city>
            <code>06254</code>
            <country>FRANCE</country>
         </postal>
         <phone>+33 497 23 26 34</phone>
         <email>pthubert@cisco.com</email>
      </address>
   </contact>

    </section>
    <!-- contributors -->

    <section anchor="changes" numbered="true" toc="default">
      <name>Change log [RFC-Editor: Please remove]</name>
      <t>This document was developed on <eref target="https://github.com/anima-wg/autonomic-control-plane/tree/master/draft-ietf-anima-autonomic-control-plane"/>. That github repository also contains the document review/reply emails.</t>

      <section numbered="true" toc="default">
        <name>Summary of changes since entering IESG review</name>
        <t>This text replaces the prior changelog with a summary showOnFrontPage="true"/>
            </author>
            <date year="1997" month="March"/>
            <abstract>
              <t indent="0">In many standards track documents several words are used to provide guidance for further IESG review.</t>
        <t>Please see revision -21 for signify the individual changelogs of prior versions .</t>
        <section numbered="true" toc="default">
          <name>Reviews (while requirements in IESG review status) / status</name>
          <t>This document entered IESG review with version -13. It has since seen the following reviews:</t>
          <t/>
          <t>IESG: Original owner/Yes: Terry Manderson (INT).</t>
          <t>IESG: No Objection: Deborah Brungard (RTG), Alissa Cooper (GEN), Warren Kumari (OPS), Mirja Kuehlewind (TSV), Alexey Melnikov (ART), Adam Roach (ART).</t>
          <t>IESG: No Objection, not counted anymore specification.  These words are often capitalized. This document defines these words as they have left IESG: Ben Campbell (ART), Spencer Dawkins (TSV).</t>
          <t>IESG: Open DISCUSS hopefully resolved by this version: Eric Rescorla (SEC, left IESG), Benjamin Kaduk (SEC).</t>
          <t>Other: Michael Richardson (WG), Brian Carpenter (WG), Pascal Thubert (WG), Frank Xialiang (WG), Elwyn Davies (GEN), Joel Halpern (RTGdir), Yongkang Zhang (WG), William Atwood (WG).</t>
        </section>
        <section numbered="true" toc="default">
          <name>BRSKI / ACP registrar related enhancements</name>
          <t>Only after ACP entered IESG review did it become clear that the in-progress BRSKI should be interpreted in IETF documents.  This document would not provide all specifies an Internet Best Current Practices for the explanations needed Internet Community, and requests discussion and suggestions for ACP registrars as expected earlier by ACP authors. Instead, BRSKI will only specify a subset of required ACP behavior related to certificate handling improvements.</t>
            </abstract>
          </front>
          <seriesInfo name="BCP" value="14"/>
          <seriesInfo name="RFC" value="2119"/>
          <seriesInfo name="DOI" value="10.17487/RFC2119"/>
        </reference>
        <reference anchor="RFC3810" target="https://www.rfc-editor.org/info/rfc3810" quoteTitle="true" derivedAnchor="RFC3810">
          <front>
            <title>Multicast Listener Discovery Version 2 (MLDv2) for IPv6</title>
            <author initials="R." surname="Vida" fullname="R. Vida" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="L." surname="Costa" fullname="L. Costa" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2004" month="June"/>
            <abstract>
              <t indent="0">This document updates RFC 2710, and registrar. There, it became clear that specifies Version 2 of the ACP draft should specify generic ACP registrar behavior independent ulticast Listener Discovery Protocol (MLDv2).  MLD is used by an IPv6 router to discover the presence of BRSKI so ACP could multicast listeners on directly attached links, and to discover which multicast addresses are of interest to those neighboring nodes.  MLDv2 is designed to be implemented interoperable with or without BRSKI and any manual/proprietary or future standardized BRSKI alternatives (for example via NETCONF) would understand MLDv1.  MLDv2 adds the requirements ability for ACP registrars and its certificate handling.</t>
          <t>This lead a node to additional text about ACP registrars report interest in the ACP document:</t>
          <t>1. Defined relationship ACP / ANI (ANI = ACP + BRSKI).</t>
          <t>6.1.4 (new) Overview of TA required for ACP.</t>
          <t>6.1.5.5 Added explanations/requirements for Re-enrollment.</t>
          <t>6.10.7 Normative requirements for ACP registrars (BRSKI or not).</t>
          <t>10.2 Operational expectations against ACP registrars (BRSKI or not).</t>
        </section>
        <section numbered="true" toc="default">
          <name>Normative enhancements since start of IESG review</name>
          <t>In addition listening to above ACP registrar / BRSKI related enhancements there is packets with a range of minor normative (also explanatory) enhancements since the start of IESG review:</t>
          <t>6.1.1 Hex digits in ACP domain information field now upper-case (no particular multicast address only from specific reason source addresses or from all sources except that both options are equally good, but capitalized ones are used in rfc5234).</t>
          <t>6.1.5.3 Added explanations about CRLs.</t>
          <t>6.1.5.6 Added explanations of behavior under failing certificates.</t>
          <t>6.1.2 Allow ACP address '0' in ACP domain information field: presence of address indicates permission for specific source addresses.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="3810"/>
          <seriesInfo name="DOI" value="10.17487/RFC3810"/>
        </reference>
        <reference anchor="RFC4191" target="https://www.rfc-editor.org/info/rfc4191" quoteTitle="true" derivedAnchor="RFC4191">
          <front>
            <title>Default Router Preferences and More-Specific Routes</title>
            <author initials="R." surname="Draves" fullname="R. Draves">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="D." surname="Thaler" fullname="D. Thaler">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2005" month="November"/>
            <abstract>
              <t indent="0">This document describes an optional extension to build ACP secure channel Router Advertisement messages for communicating default router preferences and more-specific routes from routers to node, 0 indicates that hosts.  This improves the address ability of hosts to pick an appropriate router, especially when the node host is assigned by (future) other means than certificate.  Non-autonomic nodes have no address at all (that was in -13), multi-homed and can only connect via ACP connect interfaces to ACP.</t>
          <t>6.1.3 Distinction of real ACP nodes (with address) the routers are on different links.  The preference values and those with domain certificate without address added as a new rule to ACP domain membership check.</t>
          <t>6.6 Added throttling of secure-channel setup attempts.</t>
          <t>6.11.1.14 Removed requirement to handle unknown destination ACP traffic in low-end nodes that would never be RPL roots.</t>
          <t>6.12.5 Added recommendation specific routes advertised to use hosts require administrative configuration; they are not automatically derived from routing tables.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4191"/>
          <seriesInfo name="DOI" value="10.17487/RFC4191"/>
        </reference>
        <reference anchor="RFC4193" target="https://www.rfc-editor.org/info/rfc4193" quoteTitle="true" derivedAnchor="RFC4193">
          <front>
            <title>Unique Local IPv6 DAD.</t>
          <t>6.1.1, 6.7.1.1, 6.7.2, 6.7.3, 6.8.2 Various refined additional certificate, secure channel protocol (IPsec/IKEv2 and DTLS) Unicast Addresses</title>
            <author initials="R." surname="Hinden" fullname="R. Hinden">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="B." surname="Haberman" fullname="B. Haberman">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2005" month="October"/>
            <abstract>
              <t indent="0">This document defines an IPv6 unicast address format that is globally unique and ACP GRASP TLS protocol parameter requirements to ensure interoperating implementations (from SEC-AD review).</t>
        </section>
        <section numbered="true" toc="default">
          <name>Explanatory enhancements since start is intended for local communications, usually inside of IESG review</name>
          <t>Beyond a site. These addresses are not expected to be routable on the functional enhancements from global Internet.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4193"/>
          <seriesInfo name="DOI" value="10.17487/RFC4193"/>
        </reference>
        <reference anchor="RFC4291" target="https://www.rfc-editor.org/info/rfc4291" quoteTitle="true" derivedAnchor="RFC4291">
          <front>
            <title>IP Version 6 Addressing Architecture</title>
            <author initials="R." surname="Hinden" fullname="R. Hinden">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="S." surname="Deering" fullname="S. Deering">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2006" month="February"/>
            <abstract>
              <t indent="0">This specification defines the previous two sections, addressing architecture of the IP Version 6 (IPv6) protocol.  The document includes the mayority IPv6 addressing model, text representations of changes since -13 are additional explanations from review feedback, textual nits IPv6 addresses, definition of IPv6 unicast addresses, anycast addresses, and restructuring - with no functional requirement additions/changes.</t>
          <t>1.1 Added "applicability multicast addresses, and scope" section with summarized explanations.</t>
          <t>2.Added in-band vs. out-of-band management definitions.</t>
          <t>6.1.2 (was 6.1.1) expanded explanations of reasoning an IPv6 node's required addresses.</t>
              <t indent="0">This document obsoletes RFC 3513, "IP Version 6 Addressing Architecture".   [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4291"/>
          <seriesInfo name="DOI" value="10.17487/RFC4291"/>
        </reference>
        <reference anchor="RFC4301" target="https://www.rfc-editor.org/info/rfc4301" quoteTitle="true" derivedAnchor="RFC4301">
          <front>
            <title>Security Architecture for elements of the ACP domain information field.</t>
          <t>6.1.3 refined explanations Internet Protocol</title>
            <author initials="S." surname="Kent" fullname="S. Kent">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="K." surname="Seo" fullname="K. Seo">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2005" month="December"/>
            <abstract>
              <t indent="0">This document describes an updated version of ACP domain membership check and justifications the "Security Architecture for it.</t>
          <t>6.5 Elaborated step-by-step secure channel setup.</t>
          <t>6.10  Additional explanations IP", which is designed to provide security services for addressing modes, additional table of addressing formats (thanks MichaelR).</t>
          <t>6.10.5 introduced 'F' bit position as a better visual representation in traffic at the Vlong address space.</t>
          <t>6.11.1.1 extensive overhaul to improve readability of IP layer.  This document obsoletes RFC 2401 (November 1998).  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4301"/>
          <seriesInfo name="DOI" value="10.17487/RFC4301"/>
        </reference>
        <reference anchor="RFC4861" target="https://www.rfc-editor.org/info/rfc4861" quoteTitle="true" derivedAnchor="RFC4861">
          <front>
            <title>Neighbor Discovery for IP version 6 (IPv6)</title>
            <author initials="T." surname="Narten" fullname="T. Narten">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="E." surname="Nordmark" fullname="E. Nordmark">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="W." surname="Simpson" fullname="W. Simpson">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="H." surname="Soliman" fullname="H. Soliman">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2007" month="September"/>
            <abstract>
              <t indent="0">This document specifies the Neighbor Discovery protocol for IP Version 6.  IPv6 nodes on the same link use of RPL (from IESG feedback of non-routing/RPL experts).</t>
          <t>6.12.2 Added caution Neighbor Discovery to discover each other's presence, to determine each other's link-layer addresses, to find routers, and to maintain reachability information about unconfiguring Data-Plane IPv6 the paths to active neighbors.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4861"/>
          <seriesInfo name="DOI" value="10.17487/RFC4861"/>
        </reference>
        <reference anchor="RFC4862" target="https://www.rfc-editor.org/info/rfc4862" quoteTitle="true" derivedAnchor="RFC4862">
          <front>
            <title>IPv6 Stateless Address Autoconfiguration</title>
            <author initials="S." surname="Thomson" fullname="S. Thomson">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="T." surname="Narten" fullname="T. Narten">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="T." surname="Jinmei" fullname="T. Jinmei">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2007" month="September"/>
            <abstract>
              <t indent="0">This document specifies the steps a host takes in deciding how to autoconfigure its interfaces in IP version 6.  The autoconfiguration process includes generating a link-local address, generating global addresses via stateless address autoconfiguration, and impact the Duplicate Address Detection procedure to ACP (limitation verify the uniqueness of current ACP design, and pointint the addresses on a link.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4862"/>
          <seriesInfo name="DOI" value="10.17487/RFC4862"/>
        </reference>
        <reference anchor="RFC5234" target="https://www.rfc-editor.org/info/rfc5234" quoteTitle="true" derivedAnchor="RFC5234">
          <front>
            <title>Augmented BNF for Syntax Specifications: ABNF</title>
            <author initials="D." surname="Crocker" fullname="D. Crocker" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="P." surname="Overell" fullname="P. Overell">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2008" month="January"/>
            <abstract>
              <t indent="0">Internet technical specifications often need to more details in 10.2).</t>
          <t>10.4 New explanations / summary define a formal syntax.  Over the years, a modified version of configurations for ACP (aka: all config is undesirable Backus-Naur Form (BNF), called Augmented BNF (ABNF), has been popular among many Internet specifications.  The current specification documents ABNF. It balances compactness and only required for integrating simplicity with non-autonomic components, primarily ACP-connect reasonable representational power.  The differences between standard BNF and Registrars).</t>
          <t>11. Textually enhanced / better structured security considerations section after IESG security review.</t>
          <t>A. (new) Moved all explanations ABNF involve naming rules, repetition, alternatives, order-independence, and discussions about futures from section 10 into this new appendix. value ranges.  This text should not be removed because it captures a lot of repeated asked questions in WG and during reviews and from users, and specification also captures ideas supplies additional rule definitions and encoding for some likely important followup work. But none a core lexical analyzer of this is relevant to implementing (section 6) and operating (section 10) the ACP.</t>
        </section>
      </section>
      <section numbered="true" toc="default">
        <name>draft-ietf-anima-autonomic-control-plane-30</name>
        <t>-29 did pass all IESG DISCUSS. This version cleans up reamining comments.</t>
        <t>Planned type common to be removed section Appendix A.6 was moved into new Appendix B.1 several Internet specifications.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="STD" value="68"/>
          <seriesInfo name="RFC" value="5234"/>
          <seriesInfo name="DOI" value="10.17487/RFC5234"/>
        </reference>
        <reference anchor="RFC5246" target="https://www.rfc-editor.org/info/rfc5246" quoteTitle="true" derivedAnchor="RFC5246">
          <front>
            <title>The Transport Layer Security (TLS) Protocol Version 1.2</title>
            <author initials="T." surname="Dierks" fullname="T. Dierks">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="E." surname="Rescorla" fullname="E. Rescorla">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2008" month="August"/>
            <abstract>
              <t indent="0">This document specifies Version 1.2 of the Transport Layer Security (TLS) protocol.  The TLS protocol provides communications security over the Internet.  The protocol allows client/server applications to be amended by further A.2, A.3 containing text felt communicate in a way that is designed to be unfit prevent eavesdropping, tampering, or message forgery.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="5246"/>
          <seriesInfo name="DOI" value="10.17487/RFC5246"/>
        </reference>
        <reference anchor="RFC5280" target="https://www.rfc-editor.org/info/rfc5280" quoteTitle="true" derivedAnchor="RFC5280">
          <front>
            <title>Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile</title>
            <author initials="D." surname="Cooper" fullname="D. Cooper">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="S." surname="Santesson" fullname="S. Santesson">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="S." surname="Farrell" fullname="S. Farrell">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="S." surname="Boeyen" fullname="S. Boeyen">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="R." surname="Housley" fullname="R. Housley">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="W." surname="Polk" fullname="W. Polk">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2008" month="May"/>
            <abstract>
              <t indent="0">This memo profiles the X.509 v3 certificate and X.509 v2 certificate revocation list (CRL) for publication use in RFC (see below). Added reference to the Internet.  An overview of this last draft, approach and referencing those sections ([ACPDRAFT]).</t>
        <t>Final discussion with responsible AD (Eric Vyncke): marked all references to [ACPDRAFT] as to be removed from RFC, model is provided as this would be too unconventional. Likewise also [ACPDRAFT] reference itself. Added explanation to appendix B.</t>
        <t>Comments from Erik Kline:</t>
        <t>2. Fine tuned ULA definition.</t>
        <t>Comments Michael Richardson / Eric Vyncke.</t>
        <t>6.2.4. / 11. Removed text arguing ability how to use public CA (or not). Replaced with reference to new [ACPDRAFT] section B.3 (not an introduction.  The X.509 v3 certificate format is described in RFC) that explains current state of understanding (unfinished).</t>
        <t>B.3 New text detailling authors understanding detail, with additional information regarding the format and semantics of use Internet name forms.  Standard certificate extensions are described and two Internet-specific extensions are defined.  A set of public CA (will not be required certificate extensions is specified.  The X.509 v2 CRL format is described in RFC).</t>
        <t>Comments/proposals from Ben Kaduk:</t>
        <t>Various: Replaced RFC4492 detail along with RFC8422 which is superceeding it.</t>
        <t>6.1 Text fix for hash strength 384 bits (from SHA384); Text fix for ec_point_format extension.</t>
        <t>6.2.1 Text fixup. Removed requirements standard and Internet-specific extensions.  An algorithm for ECDH support in certificate, instead merely explaining the dependencies required IF this X.509 certification path validation is desired (educational).</t>
        <t>6.2.5.4. Fine tuning 2 sentences.</t>
        <t>6.3.2. (ACP domain memebership check) Add reference to ACPDRAFT B.2 explaining why ACP domain membership does not validate ACP address of described.  An ASN.1 module and examples are provided in the connection.</t>
        <t>6.4. Downgraded SHOULD to MAY appendices.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="5280"/>
          <seriesInfo name="DOI" value="10.17487/RFC5280"/>
        </reference>
        <reference anchor="RFC5954" target="https://www.rfc-editor.org/info/rfc5954" quoteTitle="true" derivedAnchor="RFC5954">
          <front>
            <title>Essential Correction for IPv6 ABNF and URI Comparison in new -29 suggestion how to deal with DoS attacks RFC 3261</title>
            <author initials="V." surname="Gurbani" fullname="V. Gurbani" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="B." surname="Carpenter" fullname="B. Carpenter" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="B." surname="Tate" fullname="B. Tate" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2010" month="August"/>
            <abstract>
              <t indent="0">This document corrects the Augmented Backus-Naur Form (ABNF) production rule associated with many GRASP announcements. Will also separately ask TSV ADs.</t>
        <t>6.4. Fixed extension points generating IPv6 literals in CDDL objective-value definitions (with help from Carsten/Brian).</t>
        <t>9.3.5.2. Added explanation when ACP greenfield state ends, and refined text explaining how to deal with this.</t>
        <t>11. removed duplicate paragraph (first, kept paragraph was RFC 3261. It also clarifies the fixed up, improved correct version).</t>
        <t>11. Added references to ACPDRAFT B.1, B.2 as possible future solutions for downgrade attacks.</t>
        <t>12. Fixed up text rule for IANA code point allocation request.</t>
        <t>A.6 - removed.</t>
        <t>A.9.9 - added one explanatory intro paragraph to makes it easier to distinguish this option from Uniform Resource Identifier (URI) comparison when the B.1 considerations.</t>
        <t>B.1 - new text suggested from Ben, replacing A.6 (will not be in RFC).</t>
        <t>B.2 - new text discussing why there is no network layer address verification in ACP domain membership check (will not be in RFC).</t>
        <t>B.4 - Text discussing DULL GRASP attacks via port sweeps and what do do against it.</t>
        <t>Other.</t>
        <t>1. Added sentence about FCC outage report from June as example for in-band management.</t>
        <t>15. added reference to github where document was developed (removed in RFC, part of changelog).</t>
      </section>
      <section numbered="true" toc="default">
        <name>draft-ietf-anima-autonomic-control-plane-29</name>
        <t>Comments from Robert Wilton:</t>
        <t>Improved several textual nits.</t>
        <t>Discuss/Comments from Erik Kline:</t>
        <t>Editorial suggestions and nits. Thanks!.</t>
        <t>6.1.3 Added text about how/why rsub is irrelevant for domain membership check.</t>
        <t>6.3 Added extension points to AN_ACP DULL GRASP objective because for example ACP domain certificate could be a nice optional additional parameter and prior syntax would have forced us to encode into separate objective unnecessarily.</t>
        <t>6.7 Using RFC8415 terminology for exponential backoff parameters.</t>
        <t>6.11.2 Amended ACP Sub-Addressing table with future code points, explanations and prefix announced into RPL.</t>
        <t>6.12.1.11. Reworked text to better explain how black hole route works and added expanation for prefix for manual address scheme.</t>
        <t>8.1.3. Reworked explanation of RIOs for ACP connect interfaces for Type C vs. Type A/B hosts.</t>
        <t>8.1.4. Added explanation how this "VRF select" option is required for auto-attachment of Type A/B hosts to ACP and other networks.</t>
        <t></t>
        <t>Discuss/Comments from Barry Leiba:</t>
        <t>Various editorial nits - thanks.</t>
        <t>6.1 New section pulling in TLS requirements, no need anymore to duplicat for ACP GRASP, EST, BRSKI (ACP/ANI nodes) and (if desired) OCSP/CRLDP. Added rule to start use secure channel only after negotiation has finished. Added rules not to optimize negotiation across multiple L2 interfaces to the same peer.</t>
        <t>6.6 Changed role names in secure channel negotiation process: Alice/Bob -> Decider/Follower. Explanation enhancements. Added definition for ACP nodes with "0" address.</t>
        <t>6.8.3 Improved explanation how IKEv2 forces preference of IPsec over GRE due to ACP IPsec profiles being Tunneled vs. Transport.</t>
        <t>6.8.4 Limited mentioning of DTLS version requirements to this section.</t>
        <t>6.9.2 Removed TLS requirements, they are now in 6.1.</t>
        <t>6.10.6 Removed explanation of IANA allocation requirement. Redundant - already in IANA section, and was seen as confusing.</t>
        <t>8.1.1 Clarified that there can be security impacts when weakening directly connected address RPF filtering for ACP connect interfaces.</t>
        <t></t>
        <t>Discuss/Comments from Ben Kaduk:</t>
        <t>Many good editorial improvements - thanks!.</t>
        <t>5. added explanation of what to do upon failed secure channel establishment.</t>
        <t>6.1.1. refined/extended cert public cey crypto algo and better distinguished algo for the keys of the cert and the key of the signer.</t>
        <t>6.1.1. and following: explicitly defining "serialNumber" to be the X.520 subject name serialNumber, not the certificate serial Number.</t>
        <t> 6.1.1. emhasize additional authorization step for EST servers (id-kp-cmcRA).</t>
        <t>6.1.2 changed AcpNodeName ABNF to again use 32HEXDIG instead of self-defined variation, because authors overlooked that ABNF is case agnostic (which is fine). Added recommendation to encode as lower case. Added full ABNF encoding for extensions (any characters as in "atoms" except the new "+" separator).</t>
        <t>6.1.5.3. New text to explain reason for use of HTTPS (instead of HTTP) for CRLDP and when and how to use HTTPS then.</t>
        <t>6.1.5.5. added text explaning why/how and when to maintain TA data upon failing cert renewal (one version with BRSKI, one version with other, ess secure bootstrap protocols).</t>
        <t>6.3. new text and requirement about the signaling of transport ports in DULL GRASP - benefits (no well-known ports required), and problems (additional DoS attack vector, albeit not worse than pre-existing ones, depending on setup of L2 subnets.).</t>
        <t>6.7.3.1.1. Specified AUTH_HMAC_SHA2_256_128 (as the ESP authentication algorithm).</t>
        <t>6.8.2. Added recommendations for TLS_AES_256_GCM_SHA384, TLS_CHACHA20_POLY1305_SHA256 when supporting TLS 1.3.</t>
        <t>8.2.2. Added explanation about downgrade attack across configured ACP tunnels and what to do against it.</t>
        <t>9.3.5.2. Rewrote most of section as it originally was too centric on BRSKI. Should now well describe expectations against automated bootstrap. Introduces new requirement not to call node as in support of ANI if is ALSO has TOFU bootstrap.</t>
        <t>11. Expanded text about malicious EST servers. Added paragraph about ACP secure channel downgrade attacks. Added paragraphs about private PKI as a core to allow security against fake certificates, added paragraph about considerationsproblems when using public PI.</t>
        <t>A.10.9 New appendix suggesting how to discover ACP secure channel negotiation downgrade attacks.</t>
        <t></t>
        <t>Discuss from Roman Danyliw:</t>
        <t>6.1.5.1 - Added requirement to only announce SRV.est when a working CA connection.</t>
        <t>15 - Amended security considerations with text about registrar dependencies, security of IDevID/ACP-certificate, EST-Server and GRASP for EST server discovery.</t>
        <t>Other:</t>
        <t>Conversion to XML v3. Solved empty () taxonomy xref problems. Various formatting fixes for v3.</t>
        <t>Added contributors section.</t>
      </section>
      <section numbered="true" toc="default">
        <name>draft-ietf-anima-autonomic-control-plane-28</name>
        <t>IESG review Roman Danyliw:</t>
        <t>6. Requested additional text elaborating misconfiguration plus attack vectors.</t>
        <t>6.1.3.1 Added paragraph about unsecured NTP as basis for time in the absence of other options.</t>
        <t>6.7.2 reworded text about additional secure channel protocol reqiurements.</t>
        <t> 6.7.3.1.2. Added requirement for ACP nodes supporting IKEv2 to support RFC8247 (not sure how that got dropped from prior versions.</t>
        <t>Replaced minimum crypto requirements definition via specific AES options with more generic "symmetric key/hash strength" requirements.</t>
        <t>6.10.7.3. Added example how to derive addressing scheme from IDevID (PID). Added explanation how to deal with non-persistant registrar address database (hint: it sucks or is wasteful, what did you expect).</t>
        <t>8.1.1. Added explanation for 'Physical controlled/secured'.</t>
        <t>8.1.5. Removed 'Physical controlled/secured' text, refer back to 8.1.1.</t>
        <t>8.2.1. Fixed ABNF 'or' syntax line.</t>
        <t>9.3.2. Added explanation of remote management problem with interface "down" type commands.</t>
        <t>10.2.1. Added explanations for attacks from impaired ACP nodes.</t>
        <t>11. Rewrote intro paragraph. Removed text referring to enrollment/registrars as they are out of scope of ACP (dependencies only).</t>
        <t>11. Added note about need for new protocols inside ACP to use end-to-end authentication.</t>
        <t>11. Rewrote paragraph about operator mistakes so as to be actionably. Operators must not make mistakes - but ACP minimizes the mistakes they can make.</t>
        <t>ACP domain certificate -&gt; ACP certificate.</t>
        <t>Various other cosmetic edits (thanks!) and typo fixes (sorry for not running full spell check for every version. Will definitely do before RFC editor).</t>
        <t>Other:</t>
        <t>6.12.5.2.1./6.12.5.2.2. Added text explaining link breakage wrt. RTL (came about re-analyzing behavior after question about hop count).</t>
        <t>Removed now unnecessary references for earlier rrc822Name otherName choice.</t>
      </section>
      <section numbered="true" toc="default">
        <name>draft-ietf-anima-autonomic-control-plane-27</name>
        <t>Too many revisions with too many fixes. Lets do a one-word change revision for a change now if it helps to accelerate the review process.</t>
        <t>Added "subjectAltName /" to make it unambiguous that AcpNodeName is indeed a SAN (from Russ).</t>
      </section>
      <section numbered="true" toc="default">
        <name>draft-ietf-anima-autonomic-control-plane-26</name>
        <t>Russ Housley review of -25.</t>
        <t>1.1 Explicit reference for TLS 1.2 RFC.</t>
        <t>2.  Changed term of "ACP Domain Information" to AcpNodeName (ASN.1) / acp-node-name (ABNF), also through rest of document.</t>
        <t>2.  Improved CA behavior definition. changed IDevID/LDevID to IDevID/LDevID certificate to be more unambiguous.</t>
        <t>2.  Changed definition of root CA to just refer to how its used in RFC7030 CA root key update, because thats the only thing relevant to ACP.</t>
        <t>6.1.1 Moved ECDH requirement to end of text as it was not related to the subject of the initial paragraps. Likewise reference to CABFORUM.</t>
        <t>6.1.1 Reduced cert key requirements to only be MUST for certs with 2048 RSA public key and P-256 curves. Reduced longer keys to SHOULD.</t>
        <t>6.1.2 Changed text for conversion from rfc822Name to otherName / AcpNode, removed all the explanations of benefits coming with rfc822Name *sob* *sob* *sob*.</t>
        <t>6.1.2.1 New ASN.1 definition for otherName / AcpNodeName.</t>
        <t>6.1.3 Fixed up text. re the handling of missing connectivity for CRLDP / OCSP.</t>
        <t>6.1.4 Fixed up text re. inability to use public CA to situation with otherName / AcpNodeName (no more ACME rfc822Name validation for us *sob* *sob* *sob*).</t>
        <t>12. Added ASN.1 registration requests to IANA section.</t>
        <t>Appenices. Minor changes for rfc822Name to otherName change.</t>
        <t>Various minor verbal fixes/enhancements.</t>
      </section>
      <section numbered="true" toc="default">
        <name>draft-ietf-anima-autonomic-control-plane-25</name>
        <t>Crypto parameter discuss from Valery Smyslov and Paul Wouters and resulting changes.</t>
        <t>6.7.2 Moved Michael Richardson suggested diagnostic of signaling TA from IPsec section to this general requirements section and added explanation how this may be inappropriate if TA payload is considered secret by TA owner.</t>
        <t>6.7.3.1 Added traffic selectors for native IPsec. Improved text explanation.</t>
        <t>6.7.3.1.2 removed misleading text about signaling TA when using intermediate certs.</t>
        <t>6.7.3.1.2 Removed requirement for 'PKCS #7 wrapped X.509 certificate' requirement on request of Valery Smyslov as it is not defined in RFC7296 and there are enough options mandated in RFC7296. Replaced with just informative text to educate readers who are not IPsec experts what the mandatory option in RFC7296 is that allows to signal certificates.</t>
        <t>6.7.3.1.2 Added SHOULD requirement how to deal with CERTREQ so that 6.7.2 requirement for TA diagnostics will work in IKEv2 (ignoring CERTREQ is permitted by IKEv2). Added explanation how this will result in TA cert diagnostics.</t>
        <t>6.7.3.1.2 Added requirement for IKEv2 to operate on link-local addresses for ACP so at to assume ACT cert as the only possible authenticator - to avoid potentialy failing section from multiple available certs on a router.</t>
        <t>6.7.3.1.2 fixed PKIX- style OID to ASN.1 object AlgorithmIdentifier (Paul).</t>
        <t>6.7.3.2 Added IPsec traffic selectors for IPsec with GRE.</t>
        <t>6.7.5 Added notion that IPsec/GRE MAY be preferred over IPsec/native. Luckily IPsec/native uses tunneling, whereas IPsec/GRE uses transport mode, and there is a long discuss whether it is permitted to even build IPsec connectings that only support transports instead of always being able to fall back to tunnel mode. Added explanatory paragraph why ACP nodes may prefer GRE over native (wonder how that was missing..).</t>
        <t>9.1.1 Added section to explain need for secure channel peer diagnostics via signaling of TA. Four examples given.</t>
        <t>Paul Wouters mentioned that ipkcs7 had to be used in some interop cases with windows CA, but that is an issue of ACP Registrar having to convert into PKCS#7 to talk to a windows CA, and this spec is not concerned with that, except to know that it is feasible, so not mentioned in text anywhere, just tracking discussion here in changelog.</t>
        <t/>
        <t>Michael Richardson:</t>
        <t>3.1.3 Added point in support of rfc822address that CA may not support to sign certificates with new attributes (such as new otherName).</t>
        <t/>
        <t>Michael Richardson/Brian Carpenter fix:</t>
        <t>6.1.5.1/6.3 Fixed GRASP examples.</t>
        <t/>
        <t>Joe Halpern review:</t>
        <t>1. Enhanded introduction text for in-band and of out-of-band, explaining how ACP is an in-band network aiming to achieve all possible benefits of an out-of-band network.</t>
        <t>1. Comprehensive explanation for term Data-Plane as it is only logically following pre-established terminology on a fully autonomic node, when used for existing nodes augmented with ACP, Data-Plane has more functionality than usually associated with the term.</t>
        <t>2. Removed explanatory text for Data-Plane, referring to section 1.</t>
        <t>2. Reduced explanation in definition of in-band (management/signaling), out-of-band-signaling, now pointing to section 1.</t>
        <t>5. Rewrote a lot of the steps (overview) as this text was not reviewed for long time. Added references to normative section for each step to hopefully avoid feedback of not explaining terms used (really not possible to give good summary without using forward references).</t>
        <t>2. Separate out-of-band-management definition from virtual out-of-band-management definition (later one for ACP).</t>
        <t>2. Added definitions for RPI and RPL.</t>
        <t>6.1.1. added note about end-to-end authentication to distinguish channel security from overall ACP security model.</t>
        <t>6.5 Fixed bugs in channel selection signaling step description (Alice vs. Bob).</t>
        <t>6.7.1 Removed redundant channel selection explanation.</t>
        <t>6.10.3 remove locator/identifier terminology from zone addressing scheme description (unnecessary), removed explanations (now in 9.4), simplified text, clarified requirement for Node-ID to be unique, recommend to use primarily zone 0.</t>
        <t>6.10.3.1 Removed. Included a lot of insufficient suggestions for future stanards extensions, most of it was wrong or would need to be revisited by WG anyhow. Idea now (just here for comment): Announce via GRASP Zone-ID (e.g. from per-zone edge-node/registrar) into a zone of the ACP so all nodes supporting the scheme can automatically self-allocate the Zone-ID.</t>
        <t>6.11.1.1 (RPL overview), eliminated redundant text.</t>
        <t>6.11.1.1.1 New subsection to better structure overview.</t>
        <t>6.11.1.1.2 New subsection to better group overview, replaced TTL explanation (just the symptom) with hopefully better reconvergence text (intent of the profile) for the ACP RPL profile.</t>
        <t>6.11.1.1.6 Added text to explain simple choice for rank_factor.</t>
        <t>6.11.1.13 moved explanation for RPI up into 6.11.1.1.</t>
        <t>6.12.5.1 rewrote section for ACP Loopback Interface.</t>
        <t>9.4 New informative/informational section for partial or incremental adoption of ACP to help understand why there is the Zone interface sub-scheme, and how to use it.</t>
        <t/>
        <t>Unrelated fixes:</t>
        <t>Ask to RFC editor to add most important abbreviations to RFC editor abbreviation list.</t>
        <t>6.10.2 changed names in ACP addressing scheme table to be less suggestive of use.</t>
        <t>Russ Hously review:</t>
        <t>2. Fixed definition of "Enrollment", "Trust Anchor", "CA", and "root CA". Changed "Certificate Authority" to "Certification Authority" throughout the document (correct term according to X.509).</t>
        <t>6.1 Fixed explanation of mutual ACP trust.</t>
        <t>6.1.1 s/X509/X509v3/.</t>
        <t>6.1.2 created bulleted lists for explanations and justifications for choices of ACP certificate encoding. No semantic changes, just to make it easier to refer to the points in discussions (rfcdiff seems to have a bug showing text differences due to formatting changes).</t>
        <t>6.1.3 Moved content of rule #1 into previous rule #2 because certification chain validation does imply validation of lifetime. numbers of all rules reduced by 1, changed hopefully all references to the rule numbers in the document.</t>
        <t>      Rule #3, Hopefully fixed linguistic problem self-contradiction of MUST by lower casing MUST in the explanation part and rewriting the condition when this is not applicable.</t>
        <t>6.1.4 Replaced redundant term "Trust Point" (TP) with Trust Anchor (TA"). Replaced throughout document Trust Anchor with abbreviation TA.</t>
        <t>      Enhanced several sentences/rewrote paragraphs to make explanations clearer.</t>
        <t>6.6 Added explanation how ACP nodes must throttle their attempts for connection making purely on the result of their own connection attempts, not based on those connections where they are responder.</t>
        <t/>
      </section>
      <section numbered="true" toc="default">
        <name>draft-ietf-anima-autonomic-control-plane-24</name>
        <t>Leftover from -23 review by Eric Vyncke:</t>
        <t>Swapping sections 9 and 10, section 9 was meant to be at end of document and summarize. Its not meant to be misinterpreted as introducing any new information. This did happen because section 10 was added after section 9.</t>
      </section>
      <section numbered="true" toc="default">
        <name>draft-ietf-anima-autonomic-control-plane-23</name>
        <t>Note: big rfcdiff of TOC is an rfcdiff bug, changes really minimal.</t>
        <t>Review of IPsec security with Mcr and ipsec mailing list.</t>
        <t>6.7.1 - new section: Moved general considerations for secure channel protocols here, refined them.</t>
        <t>6.7.2 - new section: Moved common requirements for secure channel protocols here, refined them.</t>
        <t>6.7.3.1.1. - improved requirements text related to RFC8221, better explamations re. HW acceleration issues.</t>
        <t>6.7.3.1.2. - improved requirements text related to RFC8247, (some requirements still discussed to be redundant, will be finalized in next weeks.</t>
        <t/>
        <t>Eric Vyncke review of -21:</t>
        <t> Only noting most important changes, long list of smaller text/readability enhancements.</t>
        <t>2. - New explanation of "normative", "informational" section title tags. alphabetic reordering of terms, refined definitions for CA, CRL. root CA.</t>
        <t>6.1.1. - explanation when IDevID parameters may be copied into LDevID.</t>
        <t>6.1.2. - Fixed hex digits in ACP domain information to lower case.</t>
        <t>6.1.3.1. - New section on Realtime clock and Time Validation.</t>
        <t>6.3 - Added explanation that DTLS means &gt;= version 1.2 (not only 1.2).</t>
        <t>6.7 - New text in this main section explaing relationship of ACP secure channels and ACP virtual interfaces - with forward references to virtual interface section.</t>
        <t>6.8.2 - reordered text and picture, no text change.</t>
        <t>6.10.7.2 - describe first how Registrar-ID can be allocted for all type of registrars, then refined text for how to potentially use MAC addresses on physical registrars.</t>
        <t>6.11.1.1 - Added text how this profile does not use Data-Plane artefacts (RPI) because hadware forwarding. This was previously hidden only later in the text.</t>
        <t>6.11.1.13. - Rewrote RPL Data-Plane artefact text. Provide decoder ring for abbreviations and all relevant RFCs.</t>
        <t>6.12.5.2. - Added more explicit text that secure channels are mapped into virtual interfaces, moved different type of interfaces used by ACP into separate subsections to be able to refer to them.</t>
        <t>7.2 - Rewrote/refined text for ACP on L2, prior text was confusing and did not well explain why ACP for L2/L3 switches can be implemented without any L2 (HW) changes. Also missing explanation of only running GRASP untagged when VLANs are used.</t>
        <t>8.1.1 - Added requirement for ACP Edge nodes to allow configurable filtering of  IPv6 RPI headers.</t>
        <t>11. - (security section). Moved explanation of address stealing from 7.2 to here.</t>
      </section>
      <section numbered="true" toc="default">
        <name>draft-ietf-anima-autonomic-control-plane-22</name>
        <t>Ben Kaduk review of -21:</t>
        <t>RFC822 encoding of ACP domain information:</t>
        <t>6.1.2 rewrote text for explaining / justifying use of rfc822name as identifier for node CP in certificate (was discussed in thread, but badly written in prior versions).</t>
        <t>6.1.2 Changed EBNF syntax to use "+" after rfcSELF because that is the known primary name to extensions separator in many email systems ("." was wrong in prior versions).</t>
        <t>6.1.2 Rewrote/improved explanations for use of rfc822name field to explain better why it is PKIX compliant and the right thing to do.</t>
        <t>Crypto parameters for IPsec:</t>
        <t>6.1 - Added explanation of why manual keying for ACP is not feasible for ACP. Surprisingly, that text did not exist. Referred to by IPsec text (6.7.1), but here is the right place to describe the reasoning.</t>
        <t>6.1.2 - Small textual refinement referring to requirements to authenticate peers (for the special cases of empty or '0' ACP address in ACP domain information field.</t>
        <t>6.3 - To better justify Bens proposed change of secure channel protocol being IPsec vs. GRASP objective being IKEv2, better explained how protocol indicated in GRASP objective-value is name of protocol used to negotiate secure channel, use example of IKEv2 to negotiate IPsec.</t>
        <t>6.7.1 - refinemenet similar to 6.3.</t>
        <t> - moved new paragraph from Bens pull request up from 6.7.1.1 to 6.7.1 as it equally applies to GRE encapped IPsec (looks nicer one level up).</t>
        <t>- created subsections 6.7.1.1 (IPsec/ESP) / 6.7.1.2 (IKEv2) to clearer distinguish between these two requirements blocks.</t>
        <t>- Refined the text in these two sections to hopefully be a good answer to Valery's concern of not randomnly mocking with existing requirements docs (rfc8247 / rfc8221).</t>
        <t>6.7.1.1.1 - IPsec/ESP requirements section:</t>
        <t>- MUST support rfc8221 mandatory EXCEPT for the superceeding requirements in this section. Previously, this was not quite clear from the text.</t>
        <t>- Hopefully persuasive explanations about the requirements levels for ENCR_AES_GCM_16, ENCR_AES_CBC, ENCR_AES_CCM_8 and ENCR_CHACHA20_POLY1305: Restructured text for why not ENCR_AES_CBC (was in prior version, just not well structured), added new expanations for ENCR_AES_CCM_8 and ENCR_CHACHA20_POLY130.</t>
        <t>- In simple terms, requirements for ENCR_AES_CBC, ENCR_AES_CCM_8, ENCR_CHACHACHA are SHOULD when they are implementable with rqual or faster performancce than ENCR_AES_GCM_16.</t>
        <t>- Removed text about "additional rfc8221" reqiurements MAY be used. Now the logic is that all other requirements apply. Hopefully we have written enough so that we prohibited downgrades.</t>
        <t>6.7.1.1.2 - RFC8247 requirements:</t>
        <t>- Added mandate to support rfc8247, added explanation that there is no "stripping down" requirement, just additional stronger requirements to mandate correct use of ACP certificartes during authentication.</t>
        <t>- refined text on identifying ACP by IPv6 address to be clearer: Identifying in the context of IKEv2 and cases for '0' in ACP domain information.</t>
        <t>- removed last two paragraphs about relationship to rfc8247, as his is now written in first paragraph of the section.</t>
        <t>End of Ben Kaduk review related fixes.</t>
        <t> Other:</t>
        <t>Forgot to update example of ACP domain information to use capitalized hex-digits as required by HEXDIG used.</t>
        <t>Added reference to RFC8316 (AN use-cases) to beginning of section 3 (ACP use cases).</t>
        <t>Small Enhanced IPsec parameters description / requirements fixes (from Michael Richardson).</t>
      </section>
    </section>
  </middle>
  <back>
    <references>
      <name>Normative References</name>
      <reference anchor="RFC1034" target="https://www.rfc-editor.org/info/rfc1034">
        <front>
          <title>Domain names - concepts and facilities</title>
          <seriesInfo name="DOI" value="10.17487/RFC1034"/>
          <seriesInfo name="RFC" value="1034"/>
          <seriesInfo name="STD" value="13"/>
          <author initials="P.V." surname="Mockapetris" fullname="P.V. Mockapetris">
            <organization/>
          </author>
          <date year="1987" month="November"/>
          <abstract>
            <t>This RFC is the revised basic definition of The Domain Name System.  It obsoletes RFC-882.  This memo describes the domain style names and their used for host address look up and electronic mail forwarding.  It discusses the clients and servers in the domain name system and the protocol used between them.</t>
          </abstract>
        </front>
      </reference>

      <reference anchor="RFC2119" target="https://www.rfc-editor.org/info/rfc2119">
        <front>
          <title>Key words for use in RFCs to Indicate Requirement Levels</title>
          <seriesInfo name="DOI" value="10.17487/RFC2119"/>
          <seriesInfo name="RFC" value="2119"/>
          <seriesInfo name="BCP" value="14"/>
          <author initials="S." surname="Bradner" fullname="S. Bradner">
            <organization/>
          </author>
          <date year="1997" month="March"/>
          <abstract>
            <t>In many standards track documents several words are used to signify the requirements in the specification.  These words are often capitalized. This document defines these words as they should be interpreted in IETF documents.  This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements.</t>
          </abstract>
        </front>
      </reference>

      <reference anchor="RFC3810" target="https://www.rfc-editor.org/info/rfc3810">
        <front>
          <title>Multicast Listener Discovery Version 2 (MLDv2) for IPv6</title>
          <seriesInfo name="DOI" value="10.17487/RFC3810"/>
          <seriesInfo name="RFC" value="3810"/>
          <author initials="R." surname="Vida" fullname="R. Vida" role="editor">
            <organization/>
          </author>
          <author initials="L." surname="Costa" fullname="L. Costa" role="editor">
            <organization/>
          </author>
          <date year="2004" month="June"/>
          <abstract>
            <t>This document updates RFC 2710, and it specifies Version 2 of the ulticast Listener Discovery Protocol (MLDv2).  MLD is used by an IPv6 router to discover the presence of multicast listeners on directly attached links, and to discover which multicast addresses are of interest to those neighboring nodes.  MLDv2 is designed to be interoperable with MLDv1.  MLDv2 adds the ability for a node to report interest in listening to packets with a particular multicast address only from specific source addresses or from all sources except for specific source addresses.  [STANDARDS-TRACK]</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC4191" target="https://www.rfc-editor.org/info/rfc4191">
        <front>
          <title>Default Router Preferences and More-Specific Routes</title>
          <seriesInfo name="DOI" value="10.17487/RFC4191"/>
          <seriesInfo name="RFC" value="4191"/>
          <author initials="R." surname="Draves" fullname="R. Draves">
            <organization/>
          </author>
          <author initials="D." surname="Thaler" fullname="D. Thaler">
            <organization/>
          </author>
          <date year="2005" month="November"/>
          <abstract>
            <t>This document describes an optional extension to Router Advertisement messages for communicating default router preferences and more-specific routes from routers to hosts.  This improves the ability of hosts to pick an appropriate router, especially when the host is multi-homed and the routers are on different links.  The preference values and specific routes advertised to hosts require administrative configuration; they are not automatically derived from routing tables.  [STANDARDS-TRACK]</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC4193" target="https://www.rfc-editor.org/info/rfc4193">
        <front>
          <title>Unique Local IPv6 Unicast Addresses</title>
          <seriesInfo name="DOI" value="10.17487/RFC4193"/>
          <seriesInfo name="RFC" value="4193"/>
          <author initials="R." surname="Hinden" fullname="R. Hinden">
            <organization/>
          </author>
          <author initials="B." surname="Haberman" fullname="B. Haberman">
            <organization/>
          </author>
          <date year="2005" month="October"/>
          <abstract>
            <t>This document defines an IPv6 unicast address format that is globally unique and is intended for local communications, usually inside of a site. These addresses are not expected to be routable on the global Internet.  [STANDARDS-TRACK]</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC4291" target="https://www.rfc-editor.org/info/rfc4291">
        <front>
          <title>IP Version 6 Addressing Architecture</title>
          <seriesInfo name="DOI" value="10.17487/RFC4291"/>
          <seriesInfo name="RFC" value="4291"/>
          <author initials="R." surname="Hinden" fullname="R. Hinden">
            <organization/>
          </author>
          <author initials="S." surname="Deering" fullname="S. Deering">
            <organization/>
          </author>
          <date year="2006" month="February"/>
          <abstract>
            <t>This specification defines the addressing architecture of the IP Version 6 (IPv6) protocol.  The document includes the IPv6 addressing model, text representations of IPv6 addresses, definition of IPv6 unicast addresses, anycast addresses, and multicast addresses, and an IPv6 node's required addresses.</t>
            <t>This document obsoletes RFC 3513, "IP Version 6 Addressing Architecture".   [STANDARDS-TRACK]</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC4301" target="https://www.rfc-editor.org/info/rfc4301">
        <front>
          <title>Security Architecture for the Internet Protocol</title>
          <seriesInfo name="DOI" value="10.17487/RFC4301"/>
          <seriesInfo name="RFC" value="4301"/>
          <author initials="S." surname="Kent" fullname="S. Kent">
            <organization/>
          </author>
          <author initials="K." surname="Seo" fullname="K. Seo">
            <organization/>
          </author>
          <date year="2005" month="December"/>
          <abstract>
            <t>This document describes an updated version of the "Security Architecture for IP", which is designed to provide security services for traffic at the IP layer.  This document obsoletes RFC 2401 (November 1998).  [STANDARDS-TRACK]</t>
          </abstract>
        </front>
      </reference>

      <reference anchor="RFC4861" target="https://www.rfc-editor.org/info/rfc4861">
        <front>
          <title>Neighbor Discovery for IP version 6 (IPv6)</title>
          <seriesInfo name="DOI" value="10.17487/RFC4861"/>
          <seriesInfo name="RFC" value="4861"/>
          <author initials="T." surname="Narten" fullname="T. Narten">
            <organization/>
          </author>
          <author initials="E." surname="Nordmark" fullname="E. Nordmark">
            <organization/>
          </author>
          <author initials="W." surname="Simpson" fullname="W. Simpson">
            <organization/>
          </author>
          <author initials="H." surname="Soliman" fullname="H. Soliman">
            <organization/>
          </author>
          <date year="2007" month="September"/>
          <abstract>
            <t>This document specifies the Neighbor Discovery protocol for IP Version 6.  IPv6 nodes on the same link use Neighbor Discovery to discover each other's presence, to determine each other's link-layer addresses, to find routers, and to maintain reachability information about the paths to active neighbors.  [STANDARDS-TRACK]</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC4862" target="https://www.rfc-editor.org/info/rfc4862">
        <front>
          <title>IPv6 Stateless Address Autoconfiguration</title>
          <seriesInfo name="DOI" value="10.17487/RFC4862"/>
          <seriesInfo name="RFC" value="4862"/>
          <author initials="S." surname="Thomson" fullname="S. Thomson">
            <organization/>
          </author>
          <author initials="T." surname="Narten" fullname="T. Narten">
            <organization/>
          </author>
          <author initials="T." surname="Jinmei" fullname="T. Jinmei">
            <organization/>
          </author>
          <date year="2007" month="September"/>
          <abstract>
            <t>This document specifies the steps a host takes in deciding how to autoconfigure its interfaces in IP version 6.  The autoconfiguration process includes generating a link-local address, generating global addresses via stateless address autoconfiguration, and the Duplicate Address Detection procedure to verify the uniqueness of the addresses on a link.  [STANDARDS-TRACK]</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC5234" target="https://www.rfc-editor.org/info/rfc5234">
        <front>
          <title>Augmented BNF for Syntax Specifications: ABNF</title>
          <seriesInfo name="DOI" value="10.17487/RFC5234"/>
          <seriesInfo name="RFC" value="5234"/>
          <seriesInfo name="STD" value="68"/>
          <author initials="D." surname="Crocker" fullname="D. Crocker" role="editor">
            <organization/>
          </author>
          <author initials="P." surname="Overell" fullname="P. Overell">
            <organization/>
          </author>
          <date year="2008" month="January"/>
          <abstract>
            <t>Internet technical specifications often need to define a formal syntax.  Over the years, a modified version of Backus-Naur Form (BNF), called Augmented BNF (ABNF), has been popular among many Internet specifications.  The current specification documents ABNF. It balances compactness and simplicity with reasonable representational power.  The differences between standard BNF and ABNF involve naming rules, repetition, alternatives, order-independence, and value ranges.  This specification also supplies additional rule definitions and encoding for a core lexical analyzer of the type common to several Internet specifications.  [STANDARDS-TRACK]</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC5246" target="https://www.rfc-editor.org/info/rfc5246">
        <front>
          <title>The Transport Layer Security (TLS) Protocol Version 1.2</title>
          <seriesInfo name="DOI" value="10.17487/RFC5246"/>
          <seriesInfo name="RFC" value="5246"/>
          <author initials="T." surname="Dierks" fullname="T. Dierks">
            <organization/>
          </author>
          <author initials="E." surname="Rescorla" fullname="E. Rescorla">
            <organization/>
          </author>
          <date year="2008" month="August"/>
          <abstract>
            <t>This document specifies Version 1.2 of the Transport Layer Security (TLS) protocol.  The TLS protocol provides communications security over the Internet.  The protocol allows client/server applications to communicate in a way that is designed to prevent eavesdropping, tampering, or message forgery.  [STANDARDS-TRACK]</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC5280" target="https://www.rfc-editor.org/info/rfc5280">
        <front>
          <title>Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile</title>
          <seriesInfo name="DOI" value="10.17487/RFC5280"/>
          <seriesInfo name="RFC" value="5280"/>
          <author initials="D." surname="Cooper" fullname="D. Cooper">
            <organization/>
          </author>
          <author initials="S." surname="Santesson" fullname="S. Santesson">
            <organization/>
          </author>
          <author initials="S." surname="Farrell" fullname="S. Farrell">
            <organization/>
          </author>
          <author initials="S." surname="Boeyen" fullname="S. Boeyen">
            <organization/>
          </author>
          <author initials="R." surname="Housley" fullname="R. Housley">
            <organization/>
          </author>
          <author initials="W." surname="Polk" fullname="W. Polk">
            <organization/>
          </author>
          <date year="2008" month="May"/>
          <abstract>
            <t>This memo profiles the X.509 v3 certificate and X.509 v2 certificate revocation list (CRL) for use in the Internet.  An overview of this approach and model is provided as an introduction.  The X.509 v3 certificate format is described in detail, with additional information regarding the format and semantics of Internet name forms.  Standard certificate extensions are described and two Internet-specific extensions are defined.  A set of required certificate extensions is specified.  The X.509 v2 CRL format is described in detail along with standard and Internet-specific extensions.  An algorithm for X.509 certification path validation is described.  An ASN.1 module and examples are provided in the appendices.  [STANDARDS-TRACK]</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC6347" target="https://www.rfc-editor.org/info/rfc6347">
        <front>
          <title>Datagram Transport Layer Security Version 1.2</title>
          <seriesInfo name="DOI" value="10.17487/RFC6347"/>
          <seriesInfo name="RFC" value="6347"/>
          <author initials="E." surname="Rescorla" fullname="E. Rescorla">
            <organization/>
          </author>
          <author initials="N." surname="Modadugu" fullname="N. Modadugu">
            <organization/>
          </author>
          <date year="2012" month="January"/>
          <abstract>
            <t>This document specifies version 1.2 of the Datagram Transport Layer Security (DTLS) protocol.  The DTLS protocol provides communications privacy for datagram protocols.  The protocol allows client/server applications to communicate in a way that is designed to prevent eavesdropping, tampering, or message forgery.  The DTLS protocol is based on the Transport Layer Security (TLS) protocol and provides equivalent security guarantees.  Datagram semantics of the underlying transport are preserved by the DTLS protocol.  This document updates DTLS 1.0 to work with TLS version 1.2.  [STANDARDS-TRACK]</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC6550" target="https://www.rfc-editor.org/info/rfc6550">
        <front>
          <title>RPL: IPv6 Routing Protocol for Low-Power and Lossy Networks</title>
          <seriesInfo name="DOI" value="10.17487/RFC6550"/>
          <seriesInfo name="RFC" value="6550"/>
          <author initials="T." surname="Winter" fullname="T. Winter" role="editor">
            <organization/>
          </author>
          <author initials="P." surname="Thubert" fullname="P. Thubert" role="editor">
            <organization/>
          </author>
          <author initials="A." surname="Brandt" fullname="A. Brandt">
            <organization/>
          </author>
          <author initials="J." surname="Hui" fullname="J. Hui">
            <organization/>
          </author>
          <author initials="R." surname="Kelsey" fullname="R. Kelsey">
            <organization/>
          </author>
          <author initials="P." surname="Levis" fullname="P. Levis">
            <organization/>
          </author>
          <author initials="K." surname="Pister" fullname="K. Pister">
            <organization/>
          </author>
          <author initials="R." surname="Struik" fullname="R. Struik">
            <organization/>
          </author>
          <author initials="JP." surname="Vasseur" fullname="JP. Vasseur">
            <organization/>
          </author>
          <author initials="R." surname="Alexander" fullname="R. Alexander">
            <organization/>
          </author>
          <date year="2012" month="March"/>
          <abstract>
            <t>Low-Power and Lossy Networks (LLNs) are a class of network in which both the routers and their interconnect are constrained.  LLN routers typically operate with constraints on processing power, memory, and energy (battery power).  Their interconnects are characterized by high loss rates, low data rates, and instability.  LLNs are comprised of anything from a few dozen to thousands of routers.  Supported traffic flows include point-to-point (between devices inside the LLN), point-to-multipoint (from a central control point to a subset of devices inside the LLN), and multipoint-to-point (from devices inside the LLN towards a central control point).  This document specifies the IPv6 Routing Protocol for Low-Power and Lossy Networks (RPL), which provides a mechanism whereby multipoint-to-point traffic from devices inside the LLN towards a central control point as well as point-to-multipoint traffic from the central control point to the devices inside the LLN are supported.  Support for point-to-point traffic is also available.  [STANDARDS-TRACK]</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC6551" target="https://www.rfc-editor.org/info/rfc6551">
        <front>
          <title>Routing Metrics Used for Path Calculation in Low-Power and Lossy Networks</title>
          <seriesInfo name="DOI" value="10.17487/RFC6551"/>
          <seriesInfo name="RFC" value="6551"/>
          <author initials="JP." surname="Vasseur" fullname="JP. Vasseur" role="editor">
            <organization/>
          </author>
          <author initials="M." surname="Kim" fullname="M. Kim" role="editor">
            <organization/>
          </author>
          <author initials="K." surname="Pister" fullname="K. Pister">
            <organization/>
          </author>
          <author initials="N." surname="Dejean" fullname="N. Dejean">
            <organization/>
          </author>
          <author initials="D." surname="Barthel" fullname="D. Barthel">
            <organization/>
          </author>
          <date year="2012" month="March"/>
          <abstract>
            <t>Low-Power and Lossy Networks (LLNs) have unique characteristics compared with traditional wired and ad hoc networks that require the specification of new routing metrics and constraints.  By contrast, with typical Interior Gateway Protocol (IGP) routing metrics using hop counts or link metrics, this document specifies a set of link and node routing metrics and constraints suitable to LLNs to be used by the Routing Protocol for Low-Power and Lossy Networks (RPL).   [STANDARDS-TRACK]</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC6552" target="https://www.rfc-editor.org/info/rfc6552">
        <front>
          <title>Objective Function Zero for the Routing Protocol for Low-Power and Lossy Networks (RPL)</title>
          <seriesInfo name="DOI" value="10.17487/RFC6552"/>
          <seriesInfo name="RFC" value="6552"/>
          <author initials="P." surname="Thubert" fullname="P. Thubert" role="editor">
            <organization/>
          </author>
          <date year="2012" month="March"/>
          <abstract>
            <t>The Routing Protocol for Low-Power and Lossy Networks (RPL) specification defines a generic Distance Vector protocol that is adapted to a variety of network types by the application of specific Objective Functions (OFs).  An OF states the outcome of the process used by a RPL node to select and optimize routes within a RPL Instance based on the Information Objects available; an OF is not an algorithm.</t>
            <t>This document specifies a basic Objective Function that relies only on the objects that are defined in the RPL and does not use any protocol extensions.  [STANDARDS-TRACK]</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC6553" target="https://www.rfc-editor.org/info/rfc6553">
        <front>
          <title>The Routing Protocol for Low-Power and Lossy Networks (RPL) Option for Carrying RPL Information in Data-Plane Datagrams</title>
          <seriesInfo name="DOI" value="10.17487/RFC6553"/>
          <seriesInfo name="RFC" value="6553"/>
          <author initials="J." surname="Hui" fullname="J. Hui">
            <organization/>
          </author>
          <author initials="JP." surname="Vasseur" fullname="JP. Vasseur">
            <organization/>
          </author>
          <date year="2012" month="March"/>
          <abstract>
            <t>The Routing Protocol for Low-Power and Lossy Networks (RPL) includes routing information in data-plane datagrams to quickly identify inconsistencies in the routing topology.  This document describes the RPL Option for use among RPL routers to include such routing information.  [STANDARDS-TRACK]</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC7030" target="https://www.rfc-editor.org/info/rfc7030">
        <front>
          <title>Enrollment over Secure Transport</title>
          <seriesInfo name="DOI" value="10.17487/RFC7030"/>
          <seriesInfo name="RFC" value="7030"/>
          <author initials="M." surname="Pritikin" fullname="M. Pritikin" role="editor">
            <organization/>
          </author>
          <author initials="P." surname="Yee" fullname="P. Yee" role="editor">
            <organization/>
          </author>
          <author initials="D." surname="Harkins" fullname="D. Harkins" role="editor">
            <organization/>
          </author>
          <date year="2013" month="October"/>
          <abstract>
            <t>This document profiles certificate enrollment for clients using Certificate Management over CMS (CMC) messages over a secure transport.  This profile, called Enrollment over Secure Transport (EST), describes a simple, yet functional, certificate management protocol targeting Public Key Infrastructure (PKI) clients that need to acquire client certificates and associated Certification Authority (CA) certificates.  It also supports client-generated public/private key pairs as well as key pairs generated by the CA.</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC7296" target="https://www.rfc-editor.org/info/rfc7296">
        <front>
          <title>Internet Key Exchange Protocol Version 2 (IKEv2)</title>
          <seriesInfo name="DOI" value="10.17487/RFC7296"/>
          <seriesInfo name="RFC" value="7296"/>
          <seriesInfo name="STD" value="79"/>
          <author initials="C." surname="Kaufman" fullname="C. Kaufman">
            <organization/>
          </author>
          <author initials="P." surname="Hoffman" fullname="P. Hoffman">
            <organization/>
          </author>
          <author initials="Y." surname="Nir" fullname="Y. Nir">
            <organization/>
          </author>
          <author initials="P." surname="Eronen" fullname="P. Eronen">
            <organization/>
          </author>
          <author initials="T." surname="Kivinen" fullname="T. Kivinen">
            <organization/>
          </author>
          <date year="2014" month="October"/>
          <abstract>
            <t>This document describes version 2 of the Internet Key Exchange (IKE) protocol.  IKE is a component of IPsec used for performing mutual authentication and establishing and maintaining Security Associations (SAs).  This document obsoletes RFC 5996, and includes all of the errata for it.  It advances IKEv2 to be an Internet Standard.</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC7525" target="https://www.rfc-editor.org/info/rfc7525">
        <front>
          <title>Recommendations for Secure Use of Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS)</title>
          <seriesInfo name="DOI" value="10.17487/RFC7525"/>
          <seriesInfo name="RFC" value="7525"/>
          <seriesInfo name="BCP" value="195"/>
          <author initials="Y." surname="Sheffer" fullname="Y. Sheffer">
            <organization/>
          </author>
          <author initials="R." surname="Holz" fullname="R. Holz">
            <organization/>
          </author>
          <author initials="P." surname="Saint-Andre" fullname="P. Saint-Andre">
            <organization/>
          </author>
          <date year="2015" month="May"/>
          <abstract>
            <t>Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS) are widely used to protect data exchanged over application protocols such as HTTP, SMTP, IMAP, POP, SIP, and XMPP.  Over the last few years, several serious attacks on TLS have emerged, including attacks on its most commonly used cipher suites and their modes of operation.  This document provides recommendations for improving the security of deployed services that use TLS and DTLS. The recommendations are applicable to the majority of use cases.</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC7676" target="https://www.rfc-editor.org/info/rfc7676">
        <front>
          <title>IPv6 Support for Generic Routing Encapsulation (GRE)</title>
          <seriesInfo name="DOI" value="10.17487/RFC7676"/>
          <seriesInfo name="RFC" value="7676"/>
          <author initials="C." surname="Pignataro" fullname="C. Pignataro">
            <organization/>
          </author>
          <author initials="R." surname="Bonica" fullname="R. Bonica">
            <organization/>
          </author>
          <author initials="S." surname="Krishnan" fullname="S. Krishnan">
            <organization/>
          </author>
          <date year="2015" month="October"/>
          <abstract>
            <t>Generic Routing Encapsulation (GRE) can be used to carry any network- layer payload protocol over any network-layer delivery protocol. Currently, GRE procedures are specified for IPv4, used as either the payload or delivery protocol.  However, GRE procedures are not specified for IPv6.</t>
            <t>This document specifies GRE procedures for IPv6, used as either the payload or delivery protocol.</t>
          </abstract>
        </front>
      </reference>

      <reference anchor="RFC8174" target="https://www.rfc-editor.org/info/rfc8174">
        <front>
          <title>Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words</title>
          <seriesInfo name="DOI" value="10.17487/RFC8174"/>
          <seriesInfo name="RFC" value="8174"/>
          <seriesInfo name="BCP" value="14"/>
          <author initials="B." surname="Leiba" fullname="B. Leiba">
            <organization/>
          </author>
          <date year="2017" month="May"/>
          <abstract>
            <t>RFC 2119 specifies common key words that may be used in protocol  specifications.  This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the  defined special meanings.</t>
          </abstract>
        </front>
      </reference>

      <reference anchor="RFC8221" target="https://www.rfc-editor.org/info/rfc8221">
        <front>
          <title>Cryptographic Algorithm Implementation Requirements and Usage Guidance for Encapsulating Security Payload (ESP) and Authentication Header (AH)</title>
          <seriesInfo name="DOI" value="10.17487/RFC8221"/>
          <seriesInfo name="RFC" value="8221"/>
          <author initials="P." surname="Wouters" fullname="P. Wouters">
            <organization/>
          </author>
          <author initials="D." surname="Migault" fullname="D. Migault">
            <organization/>
          </author>
          <author initials="J." surname="Mattsson" fullname="J. Mattsson">
            <organization/>
          </author>
          <author initials="Y." surname="Nir" fullname="Y. Nir">
            <organization/>
          </author>
          <author initials="T." surname="Kivinen" fullname="T. Kivinen">
            <organization/>
          </author>
          <date year="2017" month="October"/>
          <abstract>
            <t>This document replaces RFC 7321, "Cryptographic Algorithm Implementation         Requirements and Usage Guidance for Encapsulating Security Payload               (ESP) and Authentication Header (AH)".  The goal of this document is to enable ESP and AH to benefit from cryptography that is up to date while making IPsec interoperable.</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC8247" target="https://www.rfc-editor.org/info/rfc8247">
        <front>
          <title>Algorithm Implementation Requirements and Usage Guidance for the Internet Key Exchange Protocol Version 2 (IKEv2)</title>
          <seriesInfo name="DOI" value="10.17487/RFC8247"/>
          <seriesInfo name="RFC" value="8247"/>
          <author initials="Y." surname="Nir" fullname="Y. Nir">
            <organization/>
          </author>
          <author initials="T." surname="Kivinen" fullname="T. Kivinen">
            <organization/>
          </author>
          <author initials="P." surname="Wouters" fullname="P. Wouters">
            <organization/>
          </author>
          <author initials="D." surname="Migault" fullname="D. Migault">
            <organization/>
          </author>
          <date year="2017" month="September"/>
          <abstract>
            <t>The IPsec series of protocols makes use of various cryptographic algorithms in order to provide security services.  The Internet Key Exchange (IKE) protocol is used to negotiate the IPsec Security Association (IPsec SA) parameters, such as which algorithms should be used.  To ensure interoperability between different implementations, it is necessary to specify a set of algorithm implementation requirements and usage guidance to ensure that there is at least one algorithm that all implementations support.  This document updates RFC 7296 and obsoletes RFC 4307 in defining the current algorithm implementation requirements and usage guidance for IKEv2, and does minor cleaning up of the IKEv2 IANA registry.  This document does not update the algorithms used for packet encryption using IPsec Encapsulating Security Payload (ESP).</t>
          </abstract>
        </front>
      </reference>

      <xi:include href="http://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.8422.xml"/>

      <reference anchor="RFC8446" target="https://www.rfc-editor.org/info/rfc8446">
        <front>
          <title>The Transport Layer Security (TLS) Protocol Version 1.3</title>
          <seriesInfo name="DOI" value="10.17487/RFC8446"/>
          <seriesInfo name="RFC" value="8446"/>
          <author initials="E." surname="Rescorla" fullname="E. Rescorla">
            <organization/>
          </author>
          <date year="2018" month="August"/>
          <abstract>
            <t>This document specifies version 1.3 of the Transport Layer Security (TLS) protocol.  TLS allows client/server applications to communicate over the Internet in a way that is designed to prevent eavesdropping, tampering, and message forgery.</t>
            <t>This document updates RFCs 5705 and 6066, and obsoletes RFCs 5077, 5246, and 6961.  This document also specifies new requirements for TLS 1.2 implementations.</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC8610" target="https://www.rfc-editor.org/info/rfc8610">
        <front>
          <title>Concise Data Definition Language (CDDL): A Notational Convention to Express Concise Binary Object Representation (CBOR) and JSON Data Structures</title>
          <seriesInfo name="DOI" value="10.17487/RFC8610"/>
          <seriesInfo name="RFC" value="8610"/>
          <author initials="H." surname="Birkholz" fullname="H. Birkholz">
            <organization/>
          </author>
          <author initials="C." surname="Vigano" fullname="C. Vigano">
            <organization/>
          </author>
          <author initials="C." surname="Bormann" fullname="C. Bormann">
            <organization/>
          </author>
          <date year="2019" month="June"/>
          <abstract>
            <t>This document proposes a notational convention to express Concise Binary Object Representation (CBOR) data structures (RFC 7049).  Its main goal is to provide an easy and unambiguous way to express structures for protocol messages and data formats that use CBOR or JSON.</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="I-D.ietf-anima-bootstrapping-keyinfra" target="http://www.ietf.org/internet-drafts/draft-ietf-anima-bootstrapping-keyinfra-43.txt">
        <front>
          <title>Bootstrapping Remote Secure Key Infrastructures (BRSKI)</title>
          <seriesInfo name="Internet-Draft" value="draft-ietf-anima-bootstrapping-keyinfra-43"/>
          <author initials="M" surname="Pritikin" fullname="Max Pritikin">
            <organization/>
          </author>
          <author initials="M" surname="Richardson" fullname="Michael Richardson">
            <organization/>
          </author>
          <author initials="T" surname="Eckert" fullname="Toerless Eckert">
            <organization/>
          </author>
          <author initials="M" surname="Behringer" fullname="Michael Behringer">
            <organization/>
          </author>
          <author initials="K" surname="Watsen" fullname="Kent Watsen">
            <organization/>
          </author>
          <date month="August" day="7" year="2020"/>
          <abstract>
            <t>This document specifies automated bootstrapping of an Autonomic Control Plane.  To do this a Secure Key Infrastructure is bootstrapped.  This is done using manufacturer-installed X.509 certificates, in combination with a manufacturer's authorizing service, both online and offline.  We call this process the Bootstrapping Remote Secure Key Infrastructure (BRSKI) protocol. Bootstrapping a new device can occur using a routable address and a cloud service, or using only link-local connectivity, or on limited/ disconnected networks.  Support for deployment models with less stringent security requirements is included.  Bootstrapping is complete when the cryptographic identity of the new key infrastructure is successfully deployed to the device.  The established secure connection can be used to deploy a locally issued certificate to the device as well.</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="I-D.ietf-anima-grasp" target="http://www.ietf.org/internet-drafts/draft-ietf-anima-grasp-15.txt">
        <front>
          <title>A Generic Autonomic Signaling Protocol (GRASP)</title>
          <seriesInfo name="Internet-Draft" value="draft-ietf-anima-grasp-15"/>
          <author initials="C" surname="Bormann" fullname="Carsten Bormann">
            <organization/>
          </author>
          <author initials="B" surname="Carpenter" fullname="Brian Carpenter">
            <organization/>
          </author>
          <author initials="B" surname="Liu" fullname="Bing Liu">
            <organization/>
          </author>
          <date month="July" day="13" year="2017"/>
          <abstract>
            <t>This document specifies the GeneRic Autonomic Signaling Protocol (GRASP), which enables autonomic nodes and autonomic service agents to dynamically discover peers, to synchronize state with each other, and to negotiate parameter settings with each other.  GRASP depends on an external security environment that is described elsewhere.  The technical objectives and parameters for specific application scenarios are to be described in separate documents.  Appendices briefly discuss requirements for the protocol and existing protocols with comparable features.</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="IKEV2IANA" target="https://www.iana.org/assignments/ikev2-parameters/ikev2-parameters.xhtml">
        <front>
          <title>Internet Key Exchange Version 2 (IKEv2) Parameters</title>
          <author fullname="IANA">
            <organization/>
          </author>
          <date/>
        </front>
      </reference>
    </references>
    <references>
      <name>Informative References</name>
      <!-- references whose text got removed over the versions of the doc:
                        <?rfc include='reference.RFC.4122'?> - No idea
                        <?rfc include='reference.RFC.5082'?> - GTSM was considered for GRASP, text removed
                        <?rfc include="reference.I-D.carpenter-anima-ani-objectives"?>
                        <?rfc include="reference.I-D.richardson-anima-6join-discovery.xml"?>
                        -->
      <reference anchor="I-D.ietf-anima-prefix-management" target="http://www.ietf.org/internet-drafts/draft-ietf-anima-prefix-management-07.txt">
        <front>
          <title>Autonomic IPv6 Edge Prefix Management in Large-scale Networks</title>
          <seriesInfo name="Internet-Draft" value="draft-ietf-anima-prefix-management-07"/>
          <author initials="S" surname="Jiang" fullname="Sheng Jiang">
            <organization/>
          </author>
          <author initials="Z" surname="Du" fullname="Zongpeng Du">
            <organization/>
          </author>
          <author initials="B" surname="Carpenter" fullname="Brian Carpenter">
            <organization/>
          </author>
          <author initials="Q" surname="Sun" fullname="Qiong Sun">
            <organization/>
          </author>
          <date month="December" day="18" year="2017"/>
          <abstract>
            <t>This document defines two autonomic technical objectives for IPv6 prefix management at the edge of large-scale ISP networks, with an extension to support IPv4 prefixes.  An important purpose of the document is to use it for validation of the design of various components of the autonomic networking infrastructure.</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="I-D.ietf-acme-star" target="http://www.ietf.org/internet-drafts/draft-ietf-acme-star-11.txt">
        <front>
          <title>Support for Short-Term, Automatically-Renewed (STAR) Certificates in Automated Certificate Management Environment (ACME)</title>
          <seriesInfo name="Internet-Draft" value="draft-ietf-acme-star-11"/>
          <author initials="Y" surname="Sheffer" fullname="Yaron Sheffer">
            <organization/>
          </author>
          <author initials="D" surname="Lopez" fullname="Diego Lopez">
            <organization/>
          </author>
          <author initials="O" surname="Dios" fullname="Oscar de Dios">
            <organization/>
          </author>
          <author initials="A" surname="Pastor" fullname="Antonio Pastor">
            <organization/>
          </author>
          <author initials="T" surname="Fossati" fullname="Thomas Fossati">
            <organization/>
          </author>
          <date month="October" day="24" year="2019"/>
          <abstract>
            <t>Public-key certificates need to be revoked when they are compromised, that is, when the associated private key is exposed to an unauthorized entity.  However the revocation process is often unreliable.  An alternative to revocation is issuing a sequence of certificates, each with a short validity period, and terminating this sequence upon compromise.  This memo proposes an ACME extension to enable the issuance of short-term and automatically renewed (STAR) X.509 certificates.  [RFC-Editor: please remove before publication]  While the draft is being developed, the editor's version can be found at https://github.com/yaronf/I-D/tree/master/STAR.</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="I-D.ietf-tls-dtls13" target="http://www.ietf.org/internet-drafts/draft-ietf-tls-dtls13-38.txt">
        <front>
          <title>The Datagram Transport Layer Security (DTLS) Protocol Version 1.3</title>
          <seriesInfo name="Internet-Draft" value="draft-ietf-tls-dtls13-38"/>
          <author initials="E" surname="Rescorla" fullname="Eric Rescorla">
            <organization/>
          </author>
          <author initials="H" surname="Tschofenig" fullname="Hannes Tschofenig">
            <organization/>
          </author>
          <author initials="N" surname="Modadugu" fullname="Nagendra Modadugu">
            <organization/>
          </author>
          <date month="May" day="29" year="2020"/>
          <abstract>
            <t>This document specifies Version 1.3 of the Datagram Transport Layer Security (DTLS) protocol.  DTLS 1.3 allows client/server applications to communicate over the Internet in a way that is designed to prevent eavesdropping, tampering, and message forgery.  The DTLS 1.3 protocol is intentionally based on the Transport Layer Security (TLS) 1.3 protocol and provides equivalent security guarantees with the exception of order protection/non-replayability. Datagram semantics of the underlying transport are preserved by the DTLS protocol.</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC1112" target="https://www.rfc-editor.org/info/rfc1112">
        <front>
          <title>Host extensions for IP multicasting</title>
          <seriesInfo name="DOI" value="10.17487/RFC1112"/>
          <seriesInfo name="RFC" value="1112"/>
          <seriesInfo name="STD" value="5"/>
          <author initials="S.E." surname="Deering" fullname="S.E. Deering">
            <organization/>
          </author>
          <date year="1989" month="August"/>
          <abstract>
            <t>This memo specifies the extensions required of a host implementation of the Internet Protocol (IP) to support multicasting.  Recommended procedure for IP multicasting in the Internet.  This RFC obsoletes RFCs 998 and 1054.  [STANDARDS-TRACK]</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC1492" target="https://www.rfc-editor.org/info/rfc1492">
        <front>
          <title>An Access Control Protocol, Sometimes Called TACACS</title>
          <seriesInfo name="DOI" value="10.17487/RFC1492"/>
          <seriesInfo name="RFC" value="1492"/>
          <author initials="C." surname="Finseth" fullname="C. Finseth">
            <organization/>
          </author>
          <date year="1993" month="July"/>
          <abstract>
            <t>This RFC documents the extended TACACS protocol use by the Cisco Systems terminal servers.  This same protocol is used by the University of Minnesota's distributed authentication system.  This memo provides information for the Internet community.  It does not specify an Internet standard.</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC1654" target="https://www.rfc-editor.org/info/rfc1654">
        <front>
          <title>A Border Gateway Protocol 4 (BGP-4)</title>
          <seriesInfo name="DOI" value="10.17487/RFC1654"/>
          <seriesInfo name="RFC" value="1654"/>
          <author initials="Y." surname="Rekhter" fullname="Y. Rekhter" role="editor">
            <organization/>
          </author>
          <author initials="T." surname="Li" fullname="T. Li" role="editor">
            <organization/>
          </author>
          <date year="1994" month="July"/>
          <abstract>
            <t>This document defines an inter-autonomous system routing protocol for the Internet.  [STANDARDS-TRACK]</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC1918" target="https://www.rfc-editor.org/info/rfc1918">
        <front>
          <title>Address Allocation for Private Internets</title>
          <seriesInfo name="DOI" value="10.17487/RFC1918"/>
          <seriesInfo name="RFC" value="1918"/>
          <seriesInfo name="BCP" value="5"/>
          <author initials="Y." surname="Rekhter" fullname="Y. Rekhter">
            <organization/>
          </author>
          <author initials="B." surname="Moskowitz" fullname="B. Moskowitz">
            <organization/>
          </author>
          <author initials="D." surname="Karrenberg" fullname="D. Karrenberg">
            <organization/>
          </author>
          <author initials="G. J." surname="de Groot" fullname="G. J. de Groot">
            <organization/>
          </author>
          <author initials="E." surname="Lear" fullname="E. Lear">
            <organization/>
          </author>
          <date year="1996" month="February"/>
          <abstract>
            <t>This document describes address allocation for private internets.  This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements.</t>
          </abstract>
        </front>
      </reference>

      <reference anchor="RFC2315" target="https://www.rfc-editor.org/info/rfc2315">
        <front>
          <title>PKCS #7: Cryptographic Message Syntax Version 1.5</title>
          <seriesInfo name="DOI" value="10.17487/RFC2315"/>
          <seriesInfo name="RFC" value="2315"/>
          <author initials="B." surname="Kaliski" fullname="B. Kaliski">
            <organization/>
          </author>
          <date year="1998" month="March"/>
          <abstract>
            <t>This document describes a general syntax for data that may have cryptography applied to it, such as digital signatures and digital envelopes.  This memo provides information for the Internet community. It does not specify an Internet standard of any kind.</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC2409" target="https://www.rfc-editor.org/info/rfc2409">
        <front>
          <title>The Internet Key Exchange (IKE)</title>
          <seriesInfo name="DOI" value="10.17487/RFC2409"/>
          <seriesInfo name="RFC" value="2409"/>
          <author initials="D." surname="Harkins" fullname="D. Harkins">
            <organization/>
          </author>
          <author initials="D." surname="Carrel" fullname="D. Carrel">
            <organization/>
          </author>
          <date year="1998" month="November"/>
          <abstract>
            <t>This memo describes a hybrid protocol. The purpose is to negotiate, and provide authenticated keying material for, security associations in a protected manner.  [STANDARDS-TRACK]</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC2865" target="https://www.rfc-editor.org/info/rfc2865">
        <front>
          <title>Remote Authentication Dial In User Service (RADIUS)</title>
          <seriesInfo name="DOI" value="10.17487/RFC2865"/>
          <seriesInfo name="RFC" value="2865"/>
          <author initials="C." surname="Rigney" fullname="C. Rigney">
            <organization/>
          </author>
          <author initials="S." surname="Willens" fullname="S. Willens">
            <organization/>
          </author>
          <author initials="A." surname="Rubens" fullname="A. Rubens">
            <organization/>
          </author>
          <author initials="W." surname="Simpson" fullname="W. Simpson">
            <organization/>
          </author>
          <date year="2000" month="June"/>
          <abstract>
            <t>This document describes a protocol for carrying authentication, authorization, and configuration information between a Network Access Server which desires to authenticate its links and a shared Authentication Server.  [STANDARDS-TRACK]</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC3164" target="https://www.rfc-editor.org/info/rfc3164">
        <front>
          <title>The BSD Syslog Protocol</title>
          <seriesInfo name="DOI" value="10.17487/RFC3164"/>
          <seriesInfo name="RFC" value="3164"/>
          <author initials="C." surname="Lonvick" fullname="C. Lonvick">
            <organization/>
          </author>
          <date year="2001" month="August"/>
          <abstract>
            <t>This document describes the observed behavior of the syslog protocol. This memo provides information for the Internet community.</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC3315" target="https://www.rfc-editor.org/info/rfc3315">
        <front>
          <title>Dynamic Host Configuration Protocol for IPv6 (DHCPv6)</title>
          <seriesInfo name="DOI" value="10.17487/RFC3315"/>
          <seriesInfo name="RFC" value="3315"/>
          <author initials="R." surname="Droms" fullname="R. Droms" role="editor">
            <organization/>
          </author>
          <author initials="J." surname="Bound" fullname="J. Bound">
            <organization/>
          </author>
          <author initials="B." surname="Volz" fullname="B. Volz">
            <organization/>
          </author>
          <author initials="T." surname="Lemon" fullname="T. Lemon">
            <organization/>
          </author>
          <author initials="C." surname="Perkins" fullname="C. Perkins">
            <organization/>
          </author>
          <author initials="M." surname="Carney" fullname="M. Carney">
            <organization/>
          </author>
          <date year="2003" month="July"/>
        </front>
      </reference>
      <reference anchor="RFC3411" target="https://www.rfc-editor.org/info/rfc3411">
        <front>
          <title>An Architecture for Describing Simple Network Management Protocol (SNMP) Management Frameworks</title>
          <seriesInfo name="DOI" value="10.17487/RFC3411"/>
          <seriesInfo name="RFC" value="3411"/>
          <seriesInfo name="STD" value="62"/>
          <author initials="D." surname="Harrington" fullname="D. Harrington">
            <organization/>
          </author>
          <author initials="R." surname="Presuhn" fullname="R. Presuhn">
            <organization/>
          </author>
          <author initials="B." surname="Wijnen" fullname="B. Wijnen">
            <organization/>
          </author>
          <date year="2002" month="December"/>
          <abstract>
            <t>This document describes an architecture for describing Simple Network Management Protocol (SNMP) Management Frameworks.  The architecture is designed to be modular to allow the evolution of the SNMP protocol standards over time.  The major portions of the architecture are an SNMP engine containing a Message Processing Subsystem, a Security Subsystem and an Access Control Subsystem, and possibly multiple SNMP applications which provide specific functional processing URIs contain textual representation of management data.  This document obsoletes RFC 2571.  [STANDARDS-TRACK]</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC3596" target="https://www.rfc-editor.org/info/rfc3596">
        <front>
          <title>DNS Extensions to Support IP Version 6</title>
          <seriesInfo name="DOI" value="10.17487/RFC3596"/>
          <seriesInfo name="RFC" value="3596"/>
          <seriesInfo name="STD" value="88"/>
          <author initials="S." surname="Thomson" fullname="S. Thomson">
            <organization/>
          </author>
          <author initials="C." surname="Huitema" fullname="C. Huitema">
            <organization/>
          </author>
          <author initials="V." surname="Ksinant" fullname="V. Ksinant">
            <organization/>
          </author>
          <author initials="M." surname="Souissi" fullname="M. Souissi">
            <organization/>
          </author>
          <date year="2003" month="October"/>
          <abstract>
            <t>This document defines the changes that need to be made to the Domain Name System (DNS) to support hosts running IP version 6 (IPv6).  The changes include a resource record type to store an IPv6 address, a domain to support lookups based on an IPv6 address, and updated definitions of existing query types that return Internet addresses as part of additional section processing.  The extensions are designed to be compatible with existing applications and, in particular, DNS implementations themselves.  [STANDARDS-TRACK]</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC3920" target="https://www.rfc-editor.org/info/rfc3920">
        <front>
          <title>Extensible Messaging and Presence Protocol (XMPP): Core</title>
          <seriesInfo name="DOI" value="10.17487/RFC3920"/>
          <seriesInfo name="RFC" value="3920"/>
          <author initials="P." surname="Saint-Andre" fullname="P. Saint-Andre" role="editor">
            <organization/>
          </author>
          <date year="2004" month="October"/>
          <abstract>
            <t>This memo defines the core features of the Extensible Messaging and Presence Protocol (XMPP), a protocol for streaming Extensible Markup Language (XML) elements in order to exchange structured information in close to real time between any two network endpoints.  While XMPP provides a generalized, extensible framework for exchanging XML data, it is used mainly for the purpose of building instant messaging and presence applications that meet the requirements of RFC 2779. addresses.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
      </reference>
      <reference anchor="RFC3954" target="https://www.rfc-editor.org/info/rfc3954">
        <front>
          <title>Cisco Systems NetFlow Services Export Version 9</title>
          <seriesInfo name="DOI" value="10.17487/RFC3954"/>
          <seriesInfo name="RFC" value="3954"/>
          <author initials="B." surname="Claise" fullname="B. Claise" role="editor">
            <organization/>
          </author>
          <date year="2004" month="October"/>
          <abstract>
            <t>This document specifies the data export format for version 9 of Cisco Systems' NetFlow services, for use by implementations on the network elements and/or matching collector programs.  The version 9 export format uses templates to provide access to observations of IP packet flows in a flexible and extensible manner.  A template defines a collection of fields, with corresponding descriptions of structure and semantics.  This memo provides information for the Internet community.</t>
          </abstract>
        </front> name="RFC" value="5954"/>
          <seriesInfo name="DOI" value="10.17487/RFC5954"/>
        </reference>
        <reference anchor="RFC4007" target="https://www.rfc-editor.org/info/rfc4007"> anchor="RFC6347" target="https://www.rfc-editor.org/info/rfc6347" quoteTitle="true" derivedAnchor="RFC6347">
          <front>
          <title>IPv6 Scoped Address Architecture</title>
          <seriesInfo name="DOI" value="10.17487/RFC4007"/>
          <seriesInfo name="RFC" value="4007"/>
          <author initials="S." surname="Deering" fullname="S. Deering">
            <organization/>
          </author>
          <author initials="B." surname="Haberman" fullname="B. Haberman">
            <organization/>
          </author>
          <author initials="T." surname="Jinmei" fullname="T. Jinmei">
            <organization/>
          </author>
            <title>Datagram Transport Layer Security Version 1.2</title>
            <author initials="E." surname="Nordmark" surname="Rescorla" fullname="E. Nordmark">
            <organization/> Rescorla">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="B." surname="Zill" fullname="B. Zill">
            <organization/> initials="N." surname="Modadugu" fullname="N. Modadugu">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2005" month="March"/> year="2012" month="January"/>
            <abstract>
            <t>This
              <t indent="0">This document specifies the architectural characteristics, expected behavior, textual representation, and usage of IPv6 addresses version 1.2 of different scopes.  According the Datagram Transport Layer Security (DTLS) protocol.  The DTLS protocol provides communications privacy for datagram protocols.  The protocol allows client/server applications to a decision communicate in a way that is designed to prevent eavesdropping, tampering, or message forgery.  The DTLS protocol is based on the IPv6 working group, this document intentionally avoids the syntax Transport Layer Security (TLS) protocol and usage provides equivalent security guarantees.  Datagram semantics of unicast site-local addresses. the underlying transport are preserved by the DTLS protocol.  This document updates DTLS 1.0 to work with TLS version 1.2.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6347"/>
          <seriesInfo name="DOI" value="10.17487/RFC6347"/>
        </reference>
        <reference anchor="RFC4210" target="https://www.rfc-editor.org/info/rfc4210"> anchor="RFC6550" target="https://www.rfc-editor.org/info/rfc6550" quoteTitle="true" derivedAnchor="RFC6550">
          <front>
          <title>Internet X.509 Public Key Infrastructure Certificate Management
            <title>RPL: IPv6 Routing Protocol (CMP)</title>
          <seriesInfo name="DOI" value="10.17487/RFC4210"/>
          <seriesInfo name="RFC" value="4210"/> for Low-Power and Lossy Networks</title>
            <author initials="C." surname="Adams" fullname="C. Adams">
            <organization/> initials="T." surname="Winter" fullname="T. Winter" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="S." surname="Farrell" fullname="S. Farrell">
            <organization/> initials="P." surname="Thubert" fullname="P. Thubert" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="T." surname="Kause" fullname="T. Kause">
            <organization/> initials="A." surname="Brandt" fullname="A. Brandt">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="T." surname="Mononen" fullname="T. Mononen">
            <organization/> initials="J." surname="Hui" fullname="J. Hui">
              <organization showOnFrontPage="true"/>
            </author>
          <date year="2005" month="September"/>
          <abstract>
            <t>This document describes the Internet X.509 Public Key Infrastructure (PKI) Certificate Management Protocol (CMP).  Protocol messages are defined for X.509v3 certificate creation and management.  CMP provides on-line interactions between PKI components, including an exchange between a Certification Authority (CA) and a client system.  [STANDARDS-TRACK]</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC4364" target="https://www.rfc-editor.org/info/rfc4364">
        <front>
          <title>BGP/MPLS IP Virtual Private Networks (VPNs)</title>
          <seriesInfo name="DOI" value="10.17487/RFC4364"/>
          <seriesInfo name="RFC" value="4364"/>
            <author initials="E." surname="Rosen" fullname="E. Rosen">
            <organization/> initials="R." surname="Kelsey" fullname="R. Kelsey">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="Y." surname="Rekhter" fullname="Y. Rekhter">
            <organization/> initials="P." surname="Levis" fullname="P. Levis">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="K." surname="Pister" fullname="K. Pister">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="R." surname="Struik" fullname="R. Struik">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="JP." surname="Vasseur" fullname="JP. Vasseur">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="R." surname="Alexander" fullname="R. Alexander">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2006" month="February"/> year="2012" month="March"/>
            <abstract>
            <t>This document describes a method by which a Service Provider may use an IP backbone to provide IP Virtual Private
              <t indent="0">Low-Power and Lossy Networks (VPNs) for its customers.  This method uses (LLNs) are a "peer model", class of network in which both the customers' edge routers (CE routers) send and their routes interconnect are constrained.  LLN routers typically operate with constraints on processing power, memory, and energy (battery power).  Their interconnects are characterized by high loss rates, low data rates, and instability.  LLNs are comprised of anything from a few dozen to thousands of routers.  Supported traffic flows include point-to-point (between devices inside the Service Provider's edge routers (PE routers); there is no "overlay" visible LLN), point-to-multipoint (from a central control point to a subset of devices inside the customer's routing algorithm, LLN), and CE routers at different sites do not peer with each other.  Data packets are tunneled through multipoint-to-point (from devices inside the LLN towards a central control point).  This document specifies the IPv6 Routing Protocol for Low-Power and Lossy Networks (RPL), which provides a mechanism whereby multipoint-to-point traffic from devices inside the backbone, so that LLN towards a central control point as well as point-to-multipoint traffic from the core routers do not need central control point to know the VPN routes. devices inside the LLN are supported.  Support for point-to-point traffic is also available.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6550"/>
          <seriesInfo name="DOI" value="10.17487/RFC6550"/>
        </reference>
        <reference anchor="RFC4429" target="https://www.rfc-editor.org/info/rfc4429"> anchor="RFC6551" target="https://www.rfc-editor.org/info/rfc6551" quoteTitle="true" derivedAnchor="RFC6551">
          <front>
          <title>Optimistic Duplicate Address Detection (DAD)
            <title>Routing Metrics Used for IPv6</title>
          <seriesInfo name="DOI" value="10.17487/RFC4429"/>
          <seriesInfo name="RFC" value="4429"/> Path Calculation in Low-Power and Lossy Networks</title>
            <author initials="JP." surname="Vasseur" fullname="JP. Vasseur" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="M." surname="Kim" fullname="M. Kim" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="K." surname="Pister" fullname="K. Pister">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="N." surname="Moore" surname="Dejean" fullname="N. Moore">
            <organization/> Dejean">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="D." surname="Barthel" fullname="D. Barthel">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2006" month="April"/> year="2012" month="March"/>
            <abstract>
            <t>Optimistic Duplicate Address Detection is an interoperable modification of
              <t indent="0">Low-Power and Lossy Networks (LLNs) have unique characteristics compared with traditional wired and ad hoc networks that require the existing IPv6 Neighbor Discovery (RFC 2461) specification of new routing metrics and Stateless Address Autoconfiguration (RFC 2462) processes.  The intention is constraints.  By contrast, with typical Interior Gateway Protocol (IGP) routing metrics using hop counts or link metrics, this document specifies a set of link and node routing metrics and constraints suitable to minimize address configuration delays in the successful case, LLNs to reduce disruption as far as possible in be used by the failure case, and to remain interoperable with unmodified hosts Routing Protocol for Low-Power and routers. Lossy Networks (RPL).   [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6551"/>
          <seriesInfo name="DOI" value="10.17487/RFC6551"/>
        </reference>
        <reference anchor="RFC4541" target="https://www.rfc-editor.org/info/rfc4541"> anchor="RFC6552" target="https://www.rfc-editor.org/info/rfc6552" quoteTitle="true" derivedAnchor="RFC6552">
          <front>
          <title>Considerations
            <title>Objective Function Zero for Internet Group Management the Routing Protocol (IGMP) for Low-Power and Multicast Listener Discovery (MLD) Snooping Switches</title>
          <seriesInfo name="DOI" value="10.17487/RFC4541"/>
          <seriesInfo name="RFC" value="4541"/>
          <author initials="M." surname="Christensen" fullname="M. Christensen">
            <organization/>
          </author>
          <author initials="K." surname="Kimball" fullname="K. Kimball">
            <organization/>
          </author> Lossy Networks (RPL)</title>
            <author initials="F." surname="Solensky" fullname="F. Solensky">
            <organization/> initials="P." surname="Thubert" fullname="P. Thubert" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2006" month="May"/> year="2012" month="March"/>
            <abstract>
            <t>This memo describes the recommendations for Internet Group Management
              <t indent="0">The Routing Protocol (IGMP) and Multicast Listener Discovery (MLD) snooping switches.  These are based on best current practices for IGMPv2, with further considerations for IGMPv3- Low-Power and MLDv2-snooping.  Additional areas Lossy Networks (RPL) specification defines a generic Distance Vector protocol that is adapted to a variety of relevance, such as link layer topology changes network types by the application of specific Objective Functions (OFs).  An OF states the outcome of the process used by a RPL node to select and Ethernet-specific encapsulation issues, optimize routes within a RPL Instance based on the Information Objects available; an OF is not an algorithm.</t>
              <t indent="0">This document specifies a basic Objective Function that relies only on the objects that are also considered.  This memo provides information for defined in the Internet community.</t> RPL and does not use any protocol extensions.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6552"/>
          <seriesInfo name="DOI" value="10.17487/RFC6552"/>
        </reference>
        <reference anchor="RFC4604" target="https://www.rfc-editor.org/info/rfc4604"> anchor="RFC6553" target="https://www.rfc-editor.org/info/rfc6553" quoteTitle="true" derivedAnchor="RFC6553">
          <front>
          <title>Using Internet Group Management
            <title>The Routing Protocol Version 3 (IGMPv3) for Low-Power and Multicast Listener Discovery Lossy Networks (RPL) Option for Carrying RPL Information in Data-Plane Datagrams</title>
            <author initials="J." surname="Hui" fullname="J. Hui">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="JP." surname="Vasseur" fullname="JP. Vasseur">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2012" month="March"/>
            <abstract>
              <t indent="0">The Routing Protocol Version 2 (MLDv2) for Source-Specific Multicast</title>
          <seriesInfo name="DOI" value="10.17487/RFC4604"/> Low-Power and Lossy Networks (RPL) includes routing information in data-plane datagrams to quickly identify inconsistencies in the routing topology.  This document describes the RPL Option for use among RPL routers to include such routing information.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4604"/> value="6553"/>
          <seriesInfo name="DOI" value="10.17487/RFC6553"/>
        </reference>
        <reference anchor="RFC7030" target="https://www.rfc-editor.org/info/rfc7030" quoteTitle="true" derivedAnchor="RFC7030">
          <front>
            <title>Enrollment over Secure Transport</title>
            <author initials="H." surname="Holbrook" fullname="H. Holbrook">
            <organization/> initials="M." surname="Pritikin" fullname="M. Pritikin" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="B." surname="Cain" fullname="B. Cain">
            <organization/> initials="P." surname="Yee" fullname="P. Yee" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="B." surname="Haberman" fullname="B. Haberman">
            <organization/> initials="D." surname="Harkins" fullname="D. Harkins" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2006" month="August"/> year="2013" month="October"/>
            <abstract>
            <t>The Internet Group
              <t indent="0">This document profiles certificate enrollment for clients using Certificate Management Protocol Version 3 (IGMPv3) and the Multicast Listener Discovery Protocol Version 2 (MLDv2) are protocols that allow a host to inform its neighboring routers of its desire to receive IPv4 and IPv6 multicast transmissions, respectively. Source-specific multicast (SSM) is over CMS (CMC) messages over a form of multicast in which secure transport.  This profile, called Enrollment over Secure Transport (EST), describes a receiver is required to specify both the network-layer address of the source and the multicast destination address in order simple, yet functional, certificate management protocol targeting Public Key Infrastructure (PKI) clients that need to receive the multicast transmission.  This document defines the notion of an "SSM-aware" router and host, and clarifies and (in some cases) modifies the behavior of IGMPv3 and MLDv2 on SSM-aware routers acquire client certificates and hosts to accommodate source-specific multicast.  This document updates associated Certification Authority (CA) certificates.  It also supports client-generated public/private key pairs as well as key pairs generated by the IGMPv3 and MLDv2 specifications.  [STANDARDS-TRACK]</t> CA.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="7030"/>
          <seriesInfo name="DOI" value="10.17487/RFC7030"/>
        </reference>
        <reference anchor="RFC4607" target="https://www.rfc-editor.org/info/rfc4607"> anchor="RFC7296" target="https://www.rfc-editor.org/info/rfc7296" quoteTitle="true" derivedAnchor="RFC7296">
          <front>
          <title>Source-Specific Multicast for IP</title>
          <seriesInfo name="DOI" value="10.17487/RFC4607"/>
          <seriesInfo name="RFC" value="4607"/>
            <title>Internet Key Exchange Protocol Version 2 (IKEv2)</title>
            <author initials="H." surname="Holbrook" fullname="H. Holbrook">
            <organization/> initials="C." surname="Kaufman" fullname="C. Kaufman">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="B." surname="Cain" fullname="B. Cain">
            <organization/> initials="P." surname="Hoffman" fullname="P. Hoffman">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="Y." surname="Nir" fullname="Y. Nir">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="P." surname="Eronen" fullname="P. Eronen">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="T." surname="Kivinen" fullname="T. Kivinen">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2006" month="August"/> year="2014" month="October"/>
            <abstract>
            <t>IP version 4 (IPv4) addresses in the 232/8 (232.0.0.0 to 232.255.255.255) range are designated as source-specific multicast (SSM) destination addresses and are reserved for use by source-specific applications and protocols.  For IP
              <t indent="0">This document describes version 6 (IPv6), 2 of the address prefix FF3x::/32 Internet Key Exchange (IKE) protocol.  IKE is reserved a component of IPsec used for source-specific multicast use. performing mutual authentication and establishing and maintaining Security Associations (SAs).  This document defines an extension to the Internet network service that applies to datagrams sent to SSM addresses obsoletes RFC 5996, and defines includes all of the host and router requirements errata for it.  It advances IKEv2 to support this extension.  [STANDARDS-TRACK]</t> be an Internet Standard.</t>
            </abstract>
          </front>
      </reference>
      <reference anchor="RFC4610" target="https://www.rfc-editor.org/info/rfc4610">
        <front>
          <title>Anycast-RP Using Protocol Independent Multicast (PIM)</title>
          <seriesInfo name="DOI" value="10.17487/RFC4610"/> name="STD" value="79"/>
          <seriesInfo name="RFC" value="4610"/>
          <author initials="D." surname="Farinacci" fullname="D. Farinacci">
            <organization/>
          </author> value="7296"/>
          <seriesInfo name="DOI" value="10.17487/RFC7296"/>
        </reference>
        <reference anchor="RFC7525" target="https://www.rfc-editor.org/info/rfc7525" quoteTitle="true" derivedAnchor="RFC7525">
          <front>
            <title>Recommendations for Secure Use of Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS)</title>
            <author initials="Y." surname="Cai" surname="Sheffer" fullname="Y. Cai">
            <organization/> Sheffer">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="R." surname="Holz" fullname="R. Holz">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="P." surname="Saint-Andre" fullname="P. Saint-Andre">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2006" month="August"/> year="2015" month="May"/>
            <abstract>
            <t>This specification allows Anycast-RP (Rendezvous Point)
              <t indent="0">Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS) are widely used to be protect data exchanged over application protocols such as HTTP, SMTP, IMAP, POP, SIP, and XMPP.  Over the last few years, several serious attacks on TLS have emerged, including attacks on its most commonly used inside a domain cipher suites and their modes of operation.  This document provides recommendations for improving the security of deployed services that runs Protocol Independent Multicast (PIM) only. Other multicast protocols (such as Multicast Source Discovery Protocol (MSDP), which has been used traditionally to solve this problem) use TLS and DTLS. The recommendations are not required applicable to support Anycast-RP.  [STANDARDS-TRACK]</t> the majority of use cases.</t>
            </abstract>
          </front>
          <seriesInfo name="BCP" value="195"/>
          <seriesInfo name="RFC" value="7525"/>
          <seriesInfo name="DOI" value="10.17487/RFC7525"/>
        </reference>
        <reference anchor="RFC4941" target="https://www.rfc-editor.org/info/rfc4941"> anchor="RFC7676" target="https://www.rfc-editor.org/info/rfc7676" quoteTitle="true" derivedAnchor="RFC7676">
          <front>
          <title>Privacy Extensions
            <title>IPv6 Support for Stateless Address Autoconfiguration in IPv6</title>
          <seriesInfo name="DOI" value="10.17487/RFC4941"/>
          <seriesInfo name="RFC" value="4941"/> Generic Routing Encapsulation (GRE)</title>
            <author initials="T." surname="Narten" fullname="T. Narten">
            <organization/> initials="C." surname="Pignataro" fullname="C. Pignataro">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="R." surname="Draves" surname="Bonica" fullname="R. Draves">
            <organization/> Bonica">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="S." surname="Krishnan" fullname="S. Krishnan">
            <organization/>
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2007" month="September"/> year="2015" month="October"/>
            <abstract>
            <t>Nodes use IPv6 stateless address autoconfiguration
              <t indent="0">Generic Routing Encapsulation (GRE) can be used to generate addresses using a combination of locally available information and information advertised by routers.  Addresses carry any network- layer payload protocol over any network-layer delivery protocol. Currently, GRE procedures are formed by combining network prefixes with an interface identifier.  On an interface that contains an embedded IEEE Identifier, the interface identifier is typically derived from it.  On other interface types, specified for IPv4, used as either the interface identifier is generated through other means, payload or delivery protocol.  However, GRE procedures are not specified for example, via random number generation.  This IPv6.</t>
              <t indent="0">This document describes an extension to IPv6 stateless address autoconfiguration for interfaces whose interface identifier is derived from an IEEE identifier.  Use of the extension causes nodes to generate global scope addresses from interface identifiers that change over time, even in cases where the interface contains an embedded IEEE identifier.  Changing the interface identifier (and the global scope addresses generated from it) over time makes it more difficult specifies GRE procedures for eavesdroppers and other information collectors to identify when different addresses IPv6, used in different transactions actually correspond to as either the same node.  [STANDARDS-TRACK]</t> payload or delivery protocol.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="7676"/>
          <seriesInfo name="DOI" value="10.17487/RFC7676"/>
        </reference>
        <reference anchor="RFC4985" target="https://www.rfc-editor.org/info/rfc4985"> anchor="RFC8174" target="https://www.rfc-editor.org/info/rfc8174" quoteTitle="true" derivedAnchor="RFC8174">
          <front>
          <title>Internet X.509 Public
            <title>Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Infrastructure Subject Alternative Name for Expression Words</title>
            <author initials="B." surname="Leiba" fullname="B. Leiba">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2017" month="May"/>
            <abstract>
              <t indent="0">RFC 2119 specifies common key words that may be used in protocol  specifications.  This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of Service Name</title> the key words have the  defined special meanings.</t>
            </abstract>
          </front>
          <seriesInfo name="DOI" value="10.17487/RFC4985"/> name="BCP" value="14"/>
          <seriesInfo name="RFC" value="4985"/> value="8174"/>
          <seriesInfo name="DOI" value="10.17487/RFC8174"/>
        </reference>
        <reference anchor="RFC8221" target="https://www.rfc-editor.org/info/rfc8221" quoteTitle="true" derivedAnchor="RFC8221">
          <front>
            <title>Cryptographic Algorithm Implementation Requirements and Usage Guidance for Encapsulating Security Payload (ESP) and Authentication Header (AH)</title>
            <author initials="S." surname="Santesson" fullname="S. Santesson">
            <organization/> initials="P." surname="Wouters" fullname="P. Wouters">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="D." surname="Migault" fullname="D. Migault">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="J." surname="Mattsson" fullname="J. Mattsson">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="Y." surname="Nir" fullname="Y. Nir">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="T." surname="Kivinen" fullname="T. Kivinen">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2007" month="August"/> year="2017" month="October"/>
            <abstract>
            <t>This
              <t indent="0">This document defines a new name form replaces RFC 7321, "Cryptographic Algorithm Implementation         Requirements and Usage Guidance for inclusion in the otherName field Encapsulating Security Payload               (ESP) and Authentication Header (AH)".  The goal of an X.509 Subject Alternative Name extension that allows a certificate subject this document is to be associated with the service name enable ESP and domain name components of a DNS Service Resource Record.  [STANDARDS-TRACK]</t> AH to benefit from cryptography that is up to date while making IPsec interoperable.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8221"/>
          <seriesInfo name="DOI" value="10.17487/RFC8221"/>
        </reference>
        <reference anchor="RFC5790" target="https://www.rfc-editor.org/info/rfc5790"> anchor="RFC8247" target="https://www.rfc-editor.org/info/rfc8247" quoteTitle="true" derivedAnchor="RFC8247">
          <front>
          <title>Lightweight
            <title>Algorithm Implementation Requirements and Usage Guidance for the Internet Group Management Key Exchange Protocol Version 3 (IGMPv3) and Multicast Listener Discovery Version 2 (MLDv2) Protocols</title>
          <seriesInfo name="DOI" value="10.17487/RFC5790"/>
          <seriesInfo name="RFC" value="5790"/> (IKEv2)</title>
            <author initials="H." surname="Liu" fullname="H. Liu">
            <organization/> initials="Y." surname="Nir" fullname="Y. Nir">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="W." surname="Cao" fullname="W. Cao">
            <organization/> initials="T." surname="Kivinen" fullname="T. Kivinen">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="H." surname="Asaeda" fullname="H. Asaeda">
            <organization/> initials="P." surname="Wouters" fullname="P. Wouters">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="D." surname="Migault" fullname="D. Migault">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2010" month="February"/> year="2017" month="September"/>
            <abstract>
            <t>This document describes lightweight IGMPv3 and MLDv2
              <t indent="0">The IPsec series of protocols (LW- IGMPv3 and LW-MLDv2), which simplify the standard (full) versions makes use of IGMPv3 and MLDv2. various cryptographic algorithms in order to provide security services.  The interoperability with the full versions and Internet Key Exchange (IKE) protocol is used to negotiate the previous versions IPsec Security Association (IPsec SA) parameters, such as which algorithms should be used.  To ensure interoperability between different implementations, it is necessary to specify a set of IGMP algorithm implementation requirements and MLD usage guidance to ensure that there is also taken into account.   [STANDARDS-TRACK]</t> at least one algorithm that all implementations support.  This document updates RFC 7296 and obsoletes RFC 4307 in defining the current algorithm implementation requirements and usage guidance for IKEv2, and does minor cleaning up of the IKEv2 IANA registry.  This document does not update the algorithms used for packet encryption using IPsec Encapsulating Security Payload (ESP).</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8247"/>
          <seriesInfo name="DOI" value="10.17487/RFC8247"/>
        </reference>
        <reference anchor="RFC5880" target="https://www.rfc-editor.org/info/rfc5880"> anchor="RFC8422" target="https://www.rfc-editor.org/info/rfc8422" quoteTitle="true" derivedAnchor="RFC8422">
          <front>
          <title>Bidirectional Forwarding Detection (BFD)</title>
          <seriesInfo name="DOI" value="10.17487/RFC5880"/>
          <seriesInfo name="RFC" value="5880"/>
            <title>Elliptic Curve Cryptography (ECC) Cipher Suites for Transport Layer Security (TLS) Versions 1.2 and Earlier</title>
            <author initials="D." surname="Katz" fullname="D. Katz">
            <organization/> initials="Y." surname="Nir" fullname="Y. Nir">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="D." surname="Ward" fullname="D. Ward">
            <organization/> initials="S." surname="Josefsson" fullname="S. Josefsson">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="M." surname="Pegourie-Gonnard" fullname="M. Pegourie-Gonnard">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2010" month="June"/> year="2018" month="August"/>
            <abstract>
            <t>This
              <t indent="0">This document describes a protocol intended to detect faults in key exchange algorithms based on Elliptic Curve Cryptography (ECC) for the bidirectional path between two forwarding engines, including interfaces, data link(s), and to Transport Layer Security (TLS) protocol.  In particular, it specifies the extent possible use of Ephemeral Elliptic Curve Diffie-Hellman (ECDHE) key agreement in a TLS handshake and the forwarding engines themselves, with potentially very low latency.  It operates independently use of media, data protocols, the Elliptic Curve Digital Signature Algorithm (ECDSA) and routing protocols. [STANDARDS-TRACK]</t> Edwards-curve Digital Signature Algorithm (EdDSA) as authentication mechanisms.</t>
              <t indent="0">This document obsoletes RFC 4492.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8422"/>
          <seriesInfo name="DOI" value="10.17487/RFC8422"/>
        </reference>
        <reference anchor="RFC5905" target="https://www.rfc-editor.org/info/rfc5905"> anchor="RFC8446" target="https://www.rfc-editor.org/info/rfc8446" quoteTitle="true" derivedAnchor="RFC8446">
          <front>
          <title>Network Time
            <title>The Transport Layer Security (TLS) Protocol Version 4: Protocol and Algorithms Specification</title>
          <seriesInfo name="DOI" value="10.17487/RFC5905"/>
          <seriesInfo name="RFC" value="5905"/>
          <author initials="D." surname="Mills" fullname="D. Mills">
            <organization/>
          </author>
          <author initials="J." surname="Martin" fullname="J. Martin" role="editor">
            <organization/>
          </author>
          <author initials="J." surname="Burbank" fullname="J. Burbank">
            <organization/>
          </author> 1.3</title>
            <author initials="W." surname="Kasch" fullname="W. Kasch">
            <organization/> initials="E." surname="Rescorla" fullname="E. Rescorla">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2010" month="June"/> year="2018" month="August"/>
            <abstract>
            <t>The Network Time Protocol (NTP) is widely used to synchronize computer clocks in the Internet.  This
              <t indent="0">This document describes NTP version 4 (NTPv4), which is backwards compatible with NTP specifies version 3 (NTPv3), described in RFC 1305, as well as previous versions 1.3 of the Transport Layer Security (TLS) protocol. NTPv4 includes a modified protocol header  TLS allows client/server applications to accommodate communicate over the Internet Protocol version 6 address family.  NTPv4 includes fundamental improvements in the mitigation and discipline algorithms that extend the potential accuracy to the tens of microseconds with modern workstations and fast LANs.  It includes a dynamic server discovery scheme, so way that in many cases, specific server configuration is not required.  It corrects certain errors in the NTPv3 design designed to prevent eavesdropping, tampering, and implementation message forgery.</t>
              <t indent="0">This document updates RFCs 5705 and includes an optional extension mechanism.   [STANDARDS-TRACK]</t> 6066, and obsoletes RFCs 5077, 5246, and 6961.  This document also specifies new requirements for TLS 1.2 implementations.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8446"/>
          <seriesInfo name="DOI" value="10.17487/RFC8446"/>
        </reference>
        <reference anchor="RFC5912" target="https://www.rfc-editor.org/info/rfc5912"> anchor="RFC8610" target="https://www.rfc-editor.org/info/rfc8610" quoteTitle="true" derivedAnchor="RFC8610">
          <front>
          <title>New ASN.1 Modules for the Public Key Infrastructure Using X.509 (PKIX)</title>
          <seriesInfo name="DOI" value="10.17487/RFC5912"/>
          <seriesInfo name="RFC" value="5912"/>
            <title>Concise Data Definition Language (CDDL): A Notational Convention to Express Concise Binary Object Representation (CBOR) and JSON Data Structures</title>
            <author initials="P." surname="Hoffman" fullname="P. Hoffman">
            <organization/> initials="H." surname="Birkholz" fullname="H. Birkholz">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="J." surname="Schaad" fullname="J. Schaad">
            <organization/> initials="C." surname="Vigano" fullname="C. Vigano">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="C." surname="Bormann" fullname="C. Bormann">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2010" year="2019" month="June"/>
            <abstract>
            <t>The Public Key Infrastructure using X.509 (PKIX) certificate format, and many associated formats, are expressed using ASN.1.  The current ASN.1 modules conform to the 1988 version of ASN.1.  This
              <t indent="0">This document updates those ASN.1 modules to conform to the 2002 version of ASN.1. There are no bits-on-the-wire changes to any of the formats; this is simply proposes a change notational convention to the syntax.  This document express Concise Binary Object Representation (CBOR) data structures (RFC 7049).  Its main goal is not to provide an Internet  Standards Track specification; it is published easy and unambiguous way to express structures for informational  purposes.</t> protocol messages and data formats that use CBOR or JSON.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8610"/>
          <seriesInfo name="DOI" value="10.17487/RFC8610"/>
        </reference>
        <reference anchor="RFC6241" target="https://www.rfc-editor.org/info/rfc6241"> anchor="RFC8990" target="https://www.rfc-editor.org/info/rfc8990" quoteTitle="true" derivedAnchor="RFC8990">
          <front>
          <title>Network Configuration
            <title>GeneRic Autonomic Signaling Protocol (NETCONF)</title>
          <seriesInfo name="DOI" value="10.17487/RFC6241"/>
          <seriesInfo name="RFC" value="6241"/> (GRASP)</title>
            <author initials="R." surname="Enns" fullname="R. Enns" role="editor">
            <organization/> initials="C" surname="Bormann" fullname="Carsten Bormann">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="M." surname="Bjorklund" fullname="M. Bjorklund" initials="B" surname="Carpenter" fullname="Brian Carpenter" role="editor">
            <organization/>
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="J." surname="Schoenwaelder" fullname="J. Schoenwaelder" initials="B" surname="Liu" fullname="Bing Liu" role="editor">
            <organization/>
              <organization showOnFrontPage="true"/>
            </author>
            <date month="May" year="2021"/>
          </front>
          <seriesInfo name="RFC" value="8990"/>
          <seriesInfo name="DOI" value="10.17487/RFC8990"/>
        </reference>
        <reference anchor="RFC8995" target="https://www.rfc-editor.org/info/rfc8995" quoteTitle="true" derivedAnchor="RFC8995">
          <front>
            <title>Bootstrapping Remote Secure Key Infrastructure (BRSKI)</title>
            <author initials="M" surname="Pritikin" fullname="Max Pritikin">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="A." surname="Bierman" fullname="A. Bierman" role="editor">
            <organization/> initials="M" surname="Richardson" fullname="Michael C. Richardson">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="T" surname="Eckert" fullname="Toerless Eckert">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="M" surname="Behringer" fullname="Michael H. Behringer">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="K" surname="Watsen" fullname="Kent Watsen">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2011" month="June"/>
          <abstract>
            <t>The month="May" year="2021"/>
          </front>
          <seriesInfo name="RFC" value="8995"/>
          <seriesInfo name="DOI" value="10.17487/RFC8995"/>
        </reference>
      </references>
      <references pn="section-13.2">
        <name slugifiedName="name-informative-references">Informative References</name>
        <reference anchor="AR8021" target="https://1.ieee802.org/security/802-1ar" quoteTitle="true" derivedAnchor="AR8021">
          <front>
            <title>IEEE Standard for Local and metropolitan area networks - Secure Device Identity</title>
            <author>
              <organization showOnFrontPage="true">IEEE</organization>
            </author>
          </front>
          <seriesInfo name="IEEE" value="802.1AR"/>
        </reference>
        <reference anchor="CABFORUM" target="https://cabforum.org/baseline-requirements-certificate-contents/" quoteTitle="true" derivedAnchor="CABFORUM">
          <front>
            <title>Certificate Contents for Baseline SSL</title>
            <author>
              <organization showOnFrontPage="true">CA/Browser Forum</organization>
            </author>
            <date month="Nov" year="2019"/>
          </front>
        </reference>
        <reference anchor="FCC" target="https://docs.fcc.gov/public/attachments/DOC-367699A1.docx" quoteTitle="true" derivedAnchor="FCC">
          <front>
            <title>June 15, 2020 T-Mobile Network Configuration Outage Report</title>
            <author>
              <organization showOnFrontPage="true">FCC</organization>
            </author>
            <date year="2020" month="October"/>
          </front>
          <seriesInfo name="PS Docket No." value="20-183"/>
          <refcontent>A Report of the Public Safety and Homeland Security Bureau
	Federal Communications Commission</refcontent>
        </reference>
        <reference anchor="IEEE-1588-2008" target="https://standards.ieee.org/standard/1588-2008.html" quoteTitle="true" derivedAnchor="IEEE-1588-2008">
          <front>
            <title>IEEE Standard for a Precision Clock Synchronization Protocol (NETCONF) defined in this document provides mechanisms to install, manipulate, for Networked Measurement and delete the configuration of network devices.  It uses an Extensible Markup Language (XML)-based data encoding Control Systems</title>
            <author>
              <organization showOnFrontPage="true">IEEE</organization>
            </author>
            <date month="July" year="2008"/>
          </front>
          <seriesInfo name="DOI" value="10.1109/IEEESTD.2008.4579760"/>
          <seriesInfo name="IEEE" value="1588-2008"/>
        </reference>
        <reference anchor="IEEE-802.1X" target="https://standards.ieee.org/standard/802_1X-2010.html" quoteTitle="true" derivedAnchor="IEEE-802.1X">
          <front>
            <title>IEEE Standard for the configuration data as well as the protocol messages.  The NETCONF protocol operations are realized as remote procedure calls (RPCs).  This document obsoletes RFC 4741.  [STANDARDS-TRACK]</t>
          </abstract> Local and metropolitan area networks--Port-Based Network Access Control</title>
            <author>
              <organization showOnFrontPage="true">IEEE</organization>
            </author>
            <date month="February" year="2010"/>
          </front>
          <seriesInfo name="DOI" value="10.1109/IEEESTD.2010.5409813"/>
          <seriesInfo name="IEEE" value="802.1X-2010"/>
        </reference>
        <reference anchor="LLDP" target="https://standards.ieee.org/standard/802_1AB-2016.html" quoteTitle="true" derivedAnchor="LLDP">
          <front>
            <title>IEEE Standard for Local and metropolitan area networks: Station and Media Access Control Connectivity Discovery</title>
            <author>
              <organization showOnFrontPage="true">IEEE</organization>
            </author>
            <date month="March" year="2016"/>
          </front>
          <seriesInfo name="DOI" value="10.1109/IEEESTD.2016.7433915"/>
          <seriesInfo name="IEEE" value="802.1AB-2016"/>
        </reference>
        <reference anchor="RFC6335" target="https://www.rfc-editor.org/info/rfc6335"> anchor="MACSEC" target="https://standards.ieee.org/standard/802_1AE-2006.html" quoteTitle="true" derivedAnchor="MACSEC">
          <front>
          <title>Internet Assigned Numbers Authority (IANA) Procedures
            <title>IEEE Standard for the Management of the Service Name Local and Transport Protocol Port Number Registry</title> Metropolitan Area Networks: Media Access Control (MAC) Security</title>
            <author>
              <organization showOnFrontPage="true">IEEE</organization>
            </author>
            <date month="August" year="2006"/>
          </front>
          <seriesInfo name="DOI" value="10.17487/RFC6335"/>
          <seriesInfo name="RFC" value="6335"/> value="10.1109/IEEESTD.2006.245590"/>
          <seriesInfo name="BCP" value="165"/>
          <author initials="M." surname="Cotton" fullname="M. Cotton">
            <organization/>
          </author>
          <author initials="L." surname="Eggert" fullname="L. Eggert">
            <organization/>
          </author> name="IEEE" value="802.1AE-2006"/>
        </reference>
        <reference anchor="I-D.eckert-anima-noc-autoconfig" quoteTitle="true" target="https://tools.ietf.org/html/draft-eckert-anima-noc-autoconfig-00" derivedAnchor="NOC-AUTOCONFIG">
          <front>
            <title>Autoconfiguration of NOC services in ACP networks via GRASP</title>
            <author initials="J." surname="Touch" fullname="J. Touch">
            <organization/> fullname="Toerless Eckert" role="editor">
              <organization showOnFrontPage="true">Futurewei Technologies Inc.</organization>
            </author>
          <author initials="M." surname="Westerlund" fullname="M. Westerlund">
            <organization/>
            <date month="July" day="2" year="2018"/>
          </front>
          <seriesInfo name="Internet-Draft" value="draft-eckert-anima-noc-autoconfig-00"/>
          <format type="TXT" target="https://www.ietf.org/archive/id/draft-eckert-anima-noc-autoconfig-00.txt"/>
          <refcontent>Work in Progress</refcontent>
        </reference>
        <reference anchor="OP-TECH" target="https://en.wikipedia.org/w/index.php?title=Operational_technology&amp;oldid=986363045" quoteTitle="true" derivedAnchor="OP-TECH">
          <front>
            <title>Operational technology</title>
            <author>
              <organization showOnFrontPage="true">Wikipedia</organization>
            </author>
            <date month="October" year="2020"/>
          </front>
        </reference>
        <reference anchor="RFC1112" target="https://www.rfc-editor.org/info/rfc1112" quoteTitle="true" derivedAnchor="RFC1112">
          <front>
            <title>Host extensions for IP multicasting</title>
            <author initials="S." surname="Cheshire" fullname="S. Cheshire">
            <organization/> initials="S.E." surname="Deering" fullname="S.E. Deering">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2011" year="1989" month="August"/>
            <abstract>
            <t>This document defines the procedures that the Internet Assigned Numbers Authority (IANA) uses when handling assignment and other requests related to the Service Name and Transport Protocol Port Number registry.  It also discusses the rationale and principles behind these procedures and how they facilitate
              <t indent="0">This memo specifies the long-term sustainability extensions required of the registry.</t>
            <t>This document updates IANA's procedures by obsoleting the previous UDP and TCP port assignment procedures defined in Sections 8 and 9.1 a host implementation of the IANA Allocation Guidelines, and it updates the IANA service name and port assignment procedures for UDP-Lite, the Datagram Congestion Control Protocol (DCCP), and the Stream Control Transmission Internet Protocol (SCTP).  It also updates the DNS SRV specification (IP) to clarify what a service name is and how it is registered. support multicasting.  Recommended procedure for IP multicasting in the Internet.  This memo documents an Internet Best Current Practice.</t> RFC obsoletes RFCs 998 and 1054.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
      </reference>
      <reference anchor="RFC6402" target="https://www.rfc-editor.org/info/rfc6402">
        <front>
          <title>Certificate Management over CMS (CMC) Updates</title>
          <seriesInfo name="DOI" value="10.17487/RFC6402"/> name="STD" value="5"/>
          <seriesInfo name="RFC" value="6402"/> value="1112"/>
          <seriesInfo name="DOI" value="10.17487/RFC1112"/>
        </reference>
        <reference anchor="RFC1492" target="https://www.rfc-editor.org/info/rfc1492" quoteTitle="true" derivedAnchor="RFC1492">
          <front>
            <title>An Access Control Protocol, Sometimes Called TACACS</title>
            <author initials="J." surname="Schaad" fullname="J. Schaad">
            <organization/> initials="C." surname="Finseth" fullname="C. Finseth">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2011" month="November"/> year="1993" month="July"/>
            <abstract>
            <t>This document contains a set of updates to
              <t indent="0">This RFC documents the base syntax for CMC, a Certificate Management extended TACACS protocol using use by the Cryptographic Message Syntax (CMS). Cisco Systems terminal servers.  This document updates RFC 5272, RFC 5273, and RFC 5274.</t>
            <t>The new items in this document are: new controls for future work in doing server side key generation, definition of a Subject Information Access value to identify CMC servers, and same protocol is used by the registration University of a port number for TCP/IP Minnesota's distributed authentication system.  This memo provides information for the CMC service to run on.  [STANDARDS-TRACK]</t> Internet community.  It does not specify an Internet standard.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="1492"/>
          <seriesInfo name="DOI" value="10.17487/RFC1492"/>
        </reference>
        <reference anchor="RFC6407" target="https://www.rfc-editor.org/info/rfc6407"> anchor="RFC1654" target="https://www.rfc-editor.org/info/rfc1654" quoteTitle="true" derivedAnchor="RFC1654">
          <front>
          <title>The Group Domain of Interpretation</title>
          <seriesInfo name="DOI" value="10.17487/RFC6407"/>
          <seriesInfo name="RFC" value="6407"/>
          <author initials="B." surname="Weis" fullname="B. Weis">
            <organization/>
          </author>
          <author initials="S." surname="Rowles" fullname="S. Rowles">
            <organization/>
          </author>
          <author initials="T." surname="Hardjono" fullname="T. Hardjono">
            <organization/>
          </author>
          <date year="2011" month="October"/>
          <abstract>
            <t>This document describes the Group Domain of Interpretation (GDOI) protocol specified in RFC 3547.  The GDOI provides group key management to support secure group communications according to the architecture specified in RFC 4046.  The GDOI manages group security associations, which are used by IPsec and potentially other data security protocols.  This
            <title>A Border Gateway Protocol 4 (BGP-4)</title>
            <author initials="Y." surname="Rekhter" fullname="Y. Rekhter" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="T." surname="Li" fullname="T. Li" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="1994" month="July"/>
            <abstract>
              <t indent="0">This document replaces RFC 3547. defines an inter-autonomous system routing protocol for the Internet.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="1654"/>
          <seriesInfo name="DOI" value="10.17487/RFC1654"/>
        </reference>
        <reference anchor="RFC6554" target="https://www.rfc-editor.org/info/rfc6554"> anchor="RFC1918" target="https://www.rfc-editor.org/info/rfc1918" quoteTitle="true" derivedAnchor="RFC1918">
          <front>
          <title>An IPv6 Routing Header for Source Routes with the Routing Protocol
            <title>Address Allocation for Low-Power and Lossy Networks (RPL)</title>
          <seriesInfo name="DOI" value="10.17487/RFC6554"/>
          <seriesInfo name="RFC" value="6554"/> Private Internets</title>
            <author initials="J." surname="Hui" fullname="J. Hui">
            <organization/> initials="Y." surname="Rekhter" fullname="Y. Rekhter">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="JP." surname="Vasseur" fullname="JP. Vasseur">
            <organization/> initials="B." surname="Moskowitz" fullname="B. Moskowitz">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="D." surname="Culler" surname="Karrenberg" fullname="D. Culler">
            <organization/> Karrenberg">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="V." surname="Manral" fullname="V. Manral">
            <organization/> initials="G. J." surname="de Groot" fullname="G. J. de Groot">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="E." surname="Lear" fullname="E. Lear">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2012" month="March"/> year="1996" month="February"/>
            <abstract>
            <t>In Low-Power and Lossy Networks (LLNs), memory constraints on routers may limit them to maintaining, at most, a few routes.  In some configurations, it is necessary to use these memory-constrained routers to deliver datagrams to nodes within the LLN.  The Routing Protocol
              <t indent="0">This document describes address allocation for Low-Power and Lossy Networks (RPL) can be used in some deployments to store most, if not all, routes on one (e.g., the Directed Acyclic Graph (DAG) root) or a few routers and forward the IPv6 datagram using a source routing technique to avoid large routing tables on memory-constrained routers. private internets.  This document specifies a new IPv6 Routing header type an Internet Best Current Practices for delivering datagrams within a RPL routing domain.  [STANDARDS-TRACK]</t> the Internet Community, and requests discussion and suggestions for improvements.</t>
            </abstract>
          </front>
          <seriesInfo name="BCP" value="5"/>
          <seriesInfo name="RFC" value="1918"/>
          <seriesInfo name="DOI" value="10.17487/RFC1918"/>
        </reference>
        <reference anchor="RFC6724" target="https://www.rfc-editor.org/info/rfc6724"> anchor="RFC2315" target="https://www.rfc-editor.org/info/rfc2315" quoteTitle="true" derivedAnchor="RFC2315">
          <front>
          <title>Default Address Selection for Internet Protocol
            <title>PKCS #7: Cryptographic Message Syntax Version 6 (IPv6)</title>
          <seriesInfo name="DOI" value="10.17487/RFC6724"/>
          <seriesInfo name="RFC" value="6724"/>
          <author initials="D." surname="Thaler" fullname="D. Thaler" role="editor">
            <organization/>
          </author>
          <author initials="R." surname="Draves" fullname="R. Draves">
            <organization/>
          </author>
          <author initials="A." surname="Matsumoto" fullname="A. Matsumoto">
            <organization/>
          </author> 1.5</title>
            <author initials="T." surname="Chown" fullname="T. Chown">
            <organization/> initials="B." surname="Kaliski" fullname="B. Kaliski">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2012" month="September"/> year="1998" month="March"/>
            <abstract>
            <t>This
              <t indent="0">This document describes two algorithms, one a general syntax for source address selection data that may have cryptography applied to it, such as digital signatures and one for destination address selection.  The algorithms specify default behavior digital envelopes.  This memo provides information for all the Internet Protocol version 6 (IPv6) implementations.  They do community. It does not override choices made by applications or upper-layer protocols, nor do they preclude the development specify an Internet standard of more advanced mechanisms for address selection.  The two algorithms share any kind.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="2315"/>
          <seriesInfo name="DOI" value="10.17487/RFC2315"/>
        </reference>
        <reference anchor="RFC2409" target="https://www.rfc-editor.org/info/rfc2409" quoteTitle="true" derivedAnchor="RFC2409">
          <front>
            <title>The Internet Key Exchange (IKE)</title>
            <author initials="D." surname="Harkins" fullname="D. Harkins">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="D." surname="Carrel" fullname="D. Carrel">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="1998" month="November"/>
            <abstract>
              <t indent="0">This memo describes a common context, including an optional mechanism for allowing administrators hybrid protocol. The purpose is to provide policy that can override the default behavior.  In dual-stack implementations, the destination address selection algorithm can consider both IPv4 negotiate, and IPv6 addresses -- depending on the available source addresses, the algorithm might prefer IPv6 addresses over IPv4 addresses, or vice versa.</t>
            <t>Default address selection as defined provide authenticated keying material for, security associations in this specification applies to all IPv6 nodes, including both hosts and routers.  This document obsoletes RFC 3484. a protected manner.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="2409"/>
          <seriesInfo name="DOI" value="10.17487/RFC2409"/>
        </reference>
        <reference anchor="RFC6733" target="https://www.rfc-editor.org/info/rfc6733"> anchor="RFC2865" target="https://www.rfc-editor.org/info/rfc2865" quoteTitle="true" derivedAnchor="RFC2865">
          <front>
          <title>Diameter Base Protocol</title>
          <seriesInfo name="DOI" value="10.17487/RFC6733"/>
          <seriesInfo name="RFC" value="6733"/>
            <title>Remote Authentication Dial In User Service (RADIUS)</title>
            <author initials="V." surname="Fajardo" fullname="V. Fajardo" role="editor">
            <organization/> initials="C." surname="Rigney" fullname="C. Rigney">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="J." surname="Arkko" fullname="J. Arkko">
            <organization/> initials="S." surname="Willens" fullname="S. Willens">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="J." surname="Loughney" fullname="J. Loughney">
            <organization/> initials="A." surname="Rubens" fullname="A. Rubens">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="G." surname="Zorn" fullname="G. Zorn" role="editor">
            <organization/> initials="W." surname="Simpson" fullname="W. Simpson">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2012" month="October"/> year="2000" month="June"/>
            <abstract>
            <t>The Diameter base protocol is intended to provide an Authentication, Authorization, and Accounting (AAA) framework for applications such as network access or IP mobility in both local and roaming situations.  This
              <t indent="0">This document specifies the message format, transport, error reporting, accounting, and security services used by all Diameter applications.  The Diameter base describes a protocol as defined in this document obsoletes RFC 3588 for carrying authentication, authorization, and RFC 5719, configuration information between a Network Access Server which desires to authenticate its links and it must be supported by all new Diameter implementations. a shared Authentication Server.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="2865"/>
          <seriesInfo name="DOI" value="10.17487/RFC2865"/>
        </reference>
        <reference anchor="RFC6762" target="https://www.rfc-editor.org/info/rfc6762"> anchor="RFC3164" target="https://www.rfc-editor.org/info/rfc3164" quoteTitle="true" derivedAnchor="RFC3164">
          <front>
          <title>Multicast DNS</title>
          <seriesInfo name="DOI" value="10.17487/RFC6762"/>
          <seriesInfo name="RFC" value="6762"/>
          <author initials="S." surname="Cheshire" fullname="S. Cheshire">
            <organization/>
          </author>
            <title>The BSD Syslog Protocol</title>
            <author initials="M." surname="Krochmal" fullname="M. Krochmal">
            <organization/> initials="C." surname="Lonvick" fullname="C. Lonvick">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2013" month="February"/> year="2001" month="August"/>
            <abstract>
            <t>As networked devices become smaller, more portable, and more ubiquitous, the ability to operate with less configured infrastructure is increasingly important.  In particular, the ability to look up DNS resource record data types (including, but not limited to, host names) in the absence of a conventional managed DNS server is useful.</t>
            <t>Multicast DNS (mDNS) provides the ability to perform DNS-like operations on the local link in
              <t indent="0">This document describes the absence of any conventional Unicast DNS server.  In addition, Multicast DNS designates a portion observed behavior of the DNS namespace to be free syslog protocol. This memo provides information for local use, without the need to pay any annual fee, and without the need to set up delegations or otherwise configure a conventional DNS server to answer for those names.</t>
            <t>The primary benefits of Multicast DNS names are that (i) they require little or no administration or configuration to set them up, (ii) they work when no infrastructure is present, and (iii) they work during infrastructure failures.</t> Internet community.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="3164"/>
          <seriesInfo name="DOI" value="10.17487/RFC3164"/>
        </reference>
        <reference anchor="RFC6763" target="https://www.rfc-editor.org/info/rfc6763"> anchor="RFC3315" target="https://www.rfc-editor.org/info/rfc3315" quoteTitle="true" derivedAnchor="RFC3315">
          <front>
          <title>DNS-Based Service Discovery</title>
          <seriesInfo name="DOI" value="10.17487/RFC6763"/>
          <seriesInfo name="RFC" value="6763"/>
            <title>Dynamic Host Configuration Protocol for IPv6 (DHCPv6)</title>
            <author initials="S." surname="Cheshire" fullname="S. Cheshire">
            <organization/> initials="R." surname="Droms" fullname="R. Droms" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="J." surname="Bound" fullname="J. Bound">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="B." surname="Volz" fullname="B. Volz">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="T." surname="Lemon" fullname="T. Lemon">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="C." surname="Perkins" fullname="C. Perkins">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="M." surname="Krochmal" surname="Carney" fullname="M. Krochmal">
            <organization/> Carney">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2013" month="February"/> year="2003" month="July"/>
          </front>
          <seriesInfo name="RFC" value="3315"/>
          <seriesInfo name="DOI" value="10.17487/RFC3315"/>
        </reference>
        <reference anchor="RFC3411" target="https://www.rfc-editor.org/info/rfc3411" quoteTitle="true" derivedAnchor="RFC3411">
          <front>
            <title>An Architecture for Describing Simple Network Management Protocol (SNMP) Management Frameworks</title>
            <author initials="D." surname="Harrington" fullname="D. Harrington">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="R." surname="Presuhn" fullname="R. Presuhn">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="B." surname="Wijnen" fullname="B. Wijnen">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2002" month="December"/>
            <abstract>
            <t>This
              <t indent="0">This document specifies how DNS resource records are named and structured describes an architecture for describing Simple Network Management Protocol (SNMP) Management Frameworks.  The architecture is designed to facilitate service discovery.  Given a type be modular to allow the evolution of the SNMP protocol standards over time.  The major portions of service that the architecture are an SNMP engine containing a client is looking for, and Message Processing Subsystem, a domain in Security Subsystem and an Access Control Subsystem, and possibly multiple SNMP applications which the client is looking for that service, this mechanism allows clients to discover a list of named instances provide specific functional processing of that desired service, using standard DNS queries. management data.  This mechanism is referred to as DNS-based Service Discovery, or DNS-SD.</t> document obsoletes RFC 2571.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="STD" value="62"/>
          <seriesInfo name="RFC" value="3411"/>
          <seriesInfo name="DOI" value="10.17487/RFC3411"/>
        </reference>
        <reference anchor="RFC6824" target="https://www.rfc-editor.org/info/rfc6824"> anchor="RFC3596" target="https://www.rfc-editor.org/info/rfc3596" quoteTitle="true" derivedAnchor="RFC3596">
          <front>
          <title>TCP
            <title>DNS Extensions for Multipath Operation with Multiple Addresses</title>
          <seriesInfo name="DOI" value="10.17487/RFC6824"/>
          <seriesInfo name="RFC" value="6824"/> to Support IP Version 6</title>
            <author initials="A." surname="Ford" fullname="A. Ford">
            <organization/> initials="S." surname="Thomson" fullname="S. Thomson">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="C." surname="Raiciu" surname="Huitema" fullname="C. Raiciu">
            <organization/> Huitema">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="M." surname="Handley" fullname="M. Handley">
            <organization/> initials="V." surname="Ksinant" fullname="V. Ksinant">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="O." surname="Bonaventure" fullname="O. Bonaventure">
            <organization/> initials="M." surname="Souissi" fullname="M. Souissi">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2013" month="January"/> year="2003" month="October"/>
            <abstract>
            <t>TCP/IP communication is currently restricted to a single path per connection, yet multiple paths often exist between peers.  The simultaneous use of these multiple paths for a TCP/IP session would improve resource usage within the network and, thus, improve user experience through higher throughput and improved resilience to network failure.</t>
            <t>Multipath TCP provides
              <t indent="0">This document defines the ability changes that need to simultaneously use multiple paths between peers.  This document presents a set of extensions be made to traditional TCP the Domain Name System (DNS) to support multipath operation. hosts running IP version 6 (IPv6).  The protocol offers the same changes include a resource record type of service to applications as TCP (i.e., reliable bytestream), and it provides the components necessary store an IPv6 address, a domain to establish and use multiple TCP flows across potentially disjoint paths.  This  document defines support lookups based on an Experimental Protocol for the IPv6 address, and updated definitions of existing query types that return Internet community.</t> addresses as part of additional section processing.  The extensions are designed to be compatible with existing applications and, in particular, DNS implementations themselves.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
      </reference>
      <reference anchor="RFC6830" target="https://www.rfc-editor.org/info/rfc6830">
        <front>
          <title>The Locator/ID Separation Protocol (LISP)</title>
          <seriesInfo name="DOI" value="10.17487/RFC6830"/> name="STD" value="88"/>
          <seriesInfo name="RFC" value="6830"/>
          <author initials="D." surname="Farinacci" fullname="D. Farinacci">
            <organization/>
          </author>
          <author initials="V." surname="Fuller" fullname="V. Fuller">
            <organization/>
          </author>
          <author initials="D." surname="Meyer" fullname="D. Meyer">
            <organization/>
          </author> value="3596"/>
          <seriesInfo name="DOI" value="10.17487/RFC3596"/>
        </reference>
        <reference anchor="RFC3954" target="https://www.rfc-editor.org/info/rfc3954" quoteTitle="true" derivedAnchor="RFC3954">
          <front>
            <title>Cisco Systems NetFlow Services Export Version 9</title>
            <author initials="D." surname="Lewis" fullname="D. Lewis">
            <organization/> initials="B." surname="Claise" fullname="B. Claise" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2013" month="January"/> year="2004" month="October"/>
            <abstract>
            <t>This
              <t indent="0">This document describes a network-layer-based protocol that enables separation of IP addresses into two new numbering spaces: Endpoint Identifiers (EIDs) and Routing Locators (RLOCs).  No changes are required to either host protocol stacks or to specifies the "core" data export format for version 9 of Cisco Systems' NetFlow services, for use by implementations on the Internet infrastructure. network elements and/or matching collector programs.  The Locator/ID Separation Protocol (LISP) can be incrementally deployed, without a "flag day", and offers Traffic Engineering, multihoming, and mobility benefits version 9 export format uses templates to early adopters, even when there are relatively few LISP-capable sites.</t>
            <t>Design provide access to observations of IP packet flows in a flexible and development extensible manner.  A template defines a collection of LISP was largely motivated by the problem statement produced by the October 2006 IAB Routing fields, with corresponding descriptions of structure and Addressing Workshop. semantics.  This document defines an Experimental Protocol memo provides information for the Internet community.</t>
            </abstract>
          </front>
      </reference>
      <reference anchor="RFC7011" target="https://www.rfc-editor.org/info/rfc7011">
        <front>
          <title>Specification of the IP Flow Information Export (IPFIX) Protocol for the Exchange of Flow Information</title>
          <seriesInfo name="DOI" value="10.17487/RFC7011"/>
          <seriesInfo name="RFC" value="7011"/> value="3954"/>
          <seriesInfo name="STD" value="77"/> name="DOI" value="10.17487/RFC3954"/>
        </reference>
        <reference anchor="RFC4007" target="https://www.rfc-editor.org/info/rfc4007" quoteTitle="true" derivedAnchor="RFC4007">
          <front>
            <title>IPv6 Scoped Address Architecture</title>
            <author initials="B." surname="Claise" fullname="B. Claise" role="editor">
            <organization/> initials="S." surname="Deering" fullname="S. Deering">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="B." surname="Trammell" surname="Haberman" fullname="B. Trammell" role="editor">
            <organization/> Haberman">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="P." surname="Aitken" fullname="P. Aitken">
            <organization/> initials="T." surname="Jinmei" fullname="T. Jinmei">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="E." surname="Nordmark" fullname="E. Nordmark">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="B." surname="Zill" fullname="B. Zill">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2013" month="September"/> year="2005" month="March"/>
            <abstract>
            <t>This
              <t indent="0">This document specifies the IP Flow Information Export (IPFIX) protocol, which serves as a means for transmitting Traffic Flow information over the network.  In order to transmit Traffic Flow information from an Exporting Process to a Collecting Process, a common representation of flow data architectural characteristics, expected behavior, textual representation, and a standard means usage of communicating them are required.  This IPv6 addresses of different scopes.  According to a decision in the IPv6 working group, this document describes how intentionally avoids the IPFIX Data syntax and Template Records are carried over a number usage of transport protocols from an IPFIX Exporting Process to an IPFIX Collecting Process.  This document obsoletes RFC 5101.</t> unicast site-local addresses.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4007"/>
          <seriesInfo name="DOI" value="10.17487/RFC4007"/>
        </reference>
        <reference anchor="RFC7404" target="https://www.rfc-editor.org/info/rfc7404"> anchor="RFC4210" target="https://www.rfc-editor.org/info/rfc4210" quoteTitle="true" derivedAnchor="RFC4210">
          <front>
          <title>Using Only Link-Local Addressing inside an IPv6 Network</title>
          <seriesInfo name="DOI" value="10.17487/RFC7404"/>
          <seriesInfo name="RFC" value="7404"/>
            <title>Internet X.509 Public Key Infrastructure Certificate Management Protocol (CMP)</title>
            <author initials="M." surname="Behringer" fullname="M. Behringer">
            <organization/> initials="C." surname="Adams" fullname="C. Adams">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="E." surname="Vyncke" fullname="E. Vyncke">
            <organization/> initials="S." surname="Farrell" fullname="S. Farrell">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="T." surname="Kause" fullname="T. Kause">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="T." surname="Mononen" fullname="T. Mononen">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2014" month="November"/> year="2005" month="September"/>
            <abstract>
            <t>In an IPv6 network, it is possible to use only link-local addresses on infrastructure links between routers.  This
              <t indent="0">This document discusses the advantages and disadvantages of this approach to facilitate describes the decision process Internet X.509 Public Key Infrastructure (PKI) Certificate Management Protocol (CMP).  Protocol messages are defined for X.509v3 certificate creation and management.  CMP provides on-line interactions between PKI components, including an exchange between a given network.</t> Certification Authority (CA) and a client system.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4210"/>
          <seriesInfo name="DOI" value="10.17487/RFC4210"/>
        </reference>
        <reference anchor="RFC7426" target="https://www.rfc-editor.org/info/rfc7426"> anchor="RFC4364" target="https://www.rfc-editor.org/info/rfc4364" quoteTitle="true" derivedAnchor="RFC4364">
          <front>
          <title>Software-Defined Networking (SDN): Layers and Architecture Terminology</title>
          <seriesInfo name="DOI" value="10.17487/RFC7426"/>
          <seriesInfo name="RFC" value="7426"/>
            <title>BGP/MPLS IP Virtual Private Networks (VPNs)</title>
            <author initials="E." surname="Haleplidis" surname="Rosen" fullname="E. Haleplidis" role="editor">
            <organization/>
          </author>
          <author initials="K." surname="Pentikousis" fullname="K. Pentikousis" role="editor">
            <organization/>
          </author>
          <author initials="S." surname="Denazis" fullname="S. Denazis">
            <organization/>
          </author>
          <author initials="J." surname="Hadi Salim" fullname="J. Hadi Salim">
            <organization/>
          </author>
          <author initials="D." surname="Meyer" fullname="D. Meyer">
            <organization/> Rosen">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="O." surname="Koufopavlou" fullname="O. Koufopavlou">
            <organization/> initials="Y." surname="Rekhter" fullname="Y. Rekhter">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2015" month="January"/> year="2006" month="February"/>
            <abstract>
            <t>Software-Defined Networking (SDN) refers to
              <t indent="0">This document describes a new approach for network programmability, that is, the capacity to initialize, control, change, and manage network behavior dynamically via open interfaces.  SDN emphasizes the role of software in running networks through the introduction of method by which a Service Provider may use an abstraction IP backbone to provide IP Virtual Private Networks (VPNs) for the data forwarding plane and, by doing so, separates it from the control plane. its customers.  This separation allows faster innovation cycles at both planes as experience has already shown.  However, method uses a "peer model", in which the customers' edge routers (CE routers) send their routes to the Service Provider's edge routers (PE routers); there is increasing confusion as no "overlay" visible to what exactly SDN is, what the layer structure is in an SDN architecture, customer's routing algorithm, and how layers interface CE routers at different sites do not peer with each other.  This document, a product of  Data packets are tunneled through the IRTF Software-Defined Networking Research Group (SDNRG), addresses these questions and provides a concise reference for backbone, so that the SDN research community based on relevant peer-reviewed literature, core routers do not need to know the RFC series, and relevant documents by other standards organizations.</t> VPN routes.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4364"/>
          <seriesInfo name="DOI" value="10.17487/RFC4364"/>
        </reference>
        <reference anchor="RFC7435" target="https://www.rfc-editor.org/info/rfc7435" xml:base="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.7435.xml"> anchor="RFC4429" target="https://www.rfc-editor.org/info/rfc4429" quoteTitle="true" derivedAnchor="RFC4429">
          <front>
            <title>Opportunistic Security: Some Protection Most of the Time</title>
            <seriesInfo name="DOI" value="10.17487/RFC7435"/>
            <seriesInfo name="RFC" value="7435"/>
            <title>Optimistic Duplicate Address Detection (DAD) for IPv6</title>
            <author initials="V." surname="Dukhovni" fullname="V. Dukhovni">
              <organization/> initials="N." surname="Moore" fullname="N. Moore">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2014" month="December"/> year="2006" month="April"/>
            <abstract>
              <t>This document defines the concept "Opportunistic Security" in the context of communications protocols.  Protocol designs based on Opportunistic Security use encryption even when authentication
              <t indent="0">Optimistic Duplicate Address Detection is not available, an interoperable modification of the existing IPv6 Neighbor Discovery (RFC 2461) and use authentication when possible, thereby removing barriers Stateless Address Autoconfiguration (RFC 2462) processes.  The intention is to minimize address configuration delays in the widespread use of encryption on successful case, to reduce disruption as far as possible in the Internet.</t> failure case, and to remain interoperable with unmodified hosts and routers.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4429"/>
          <seriesInfo name="DOI" value="10.17487/RFC4429"/>
        </reference>
        <reference anchor="RFC7575" target="https://www.rfc-editor.org/info/rfc7575"> anchor="RFC4541" target="https://www.rfc-editor.org/info/rfc4541" quoteTitle="true" derivedAnchor="RFC4541">
          <front>
          <title>Autonomic Networking: Definitions
            <title>Considerations for Internet Group Management Protocol (IGMP) and Design Goals</title>
          <seriesInfo name="DOI" value="10.17487/RFC7575"/>
          <seriesInfo name="RFC" value="7575"/> Multicast Listener Discovery (MLD) Snooping Switches</title>
            <author initials="M." surname="Behringer" surname="Christensen" fullname="M. Behringer">
            <organization/> Christensen">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="M." surname="Pritikin" fullname="M. Pritikin">
            <organization/> initials="K." surname="Kimball" fullname="K. Kimball">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="S." surname="Bjarnason" fullname="S. Bjarnason">
            <organization/> initials="F." surname="Solensky" fullname="F. Solensky">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2006" month="May"/>
            <abstract>
              <t indent="0">This memo describes the recommendations for Internet Group Management Protocol (IGMP) and Multicast Listener Discovery (MLD) snooping switches.  These are based on best current practices for IGMPv2, with further considerations for IGMPv3- and MLDv2-snooping.  Additional areas of relevance, such as link layer topology changes and Ethernet-specific encapsulation issues, are also considered.  This memo provides information for the Internet community.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4541"/>
          <seriesInfo name="DOI" value="10.17487/RFC4541"/>
        </reference>
        <reference anchor="RFC4604" target="https://www.rfc-editor.org/info/rfc4604" quoteTitle="true" derivedAnchor="RFC4604">
          <front>
            <title>Using Internet Group Management Protocol Version 3 (IGMPv3) and Multicast Listener Discovery Protocol Version 2 (MLDv2) for Source-Specific Multicast</title>
            <author initials="A." surname="Clemm" fullname="A. Clemm">
            <organization/> initials="H." surname="Holbrook" fullname="H. Holbrook">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="B." surname="Carpenter" surname="Cain" fullname="B. Carpenter">
            <organization/>
          </author>
          <author initials="S." surname="Jiang" fullname="S. Jiang">
            <organization/> Cain">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="L." surname="Ciavaglia" fullname="L. Ciavaglia">
            <organization/> initials="B." surname="Haberman" fullname="B. Haberman">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2015" month="June"/> year="2006" month="August"/>
            <abstract>
            <t>Autonomic systems were first described
              <t indent="0">The Internet Group Management Protocol Version 3 (IGMPv3) and the Multicast Listener Discovery Protocol Version 2 (MLDv2) are protocols that allow a host to inform its neighboring routers of its desire to receive IPv4 and IPv6 multicast transmissions, respectively. Source-specific multicast (SSM) is a form of multicast in 2001.  The fundamental goal which a receiver is self-management, including self-configuration, self-optimization, self-healing, required to specify both the network-layer address of the source and self-protection.  This is achieved by an autonomic function having minimal dependencies on human administrators or centralized management systems.  It usually implies distribution across network elements.</t>
            <t>This the multicast destination address in order to receive the multicast transmission.  This document defines common language and outlines design goals (and what are not design goals) for autonomic functions.  A high-level reference model illustrates how functional elements in the notion of an Autonomic Network interact. "SSM-aware" router and host, and clarifies and (in some cases) modifies the behavior of IGMPv3 and MLDv2 on SSM-aware routers and hosts to accommodate source-specific multicast.  This document is a product of updates the IRTF's Network Management Research Group.</t> IGMPv3 and MLDv2 specifications.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4604"/>
          <seriesInfo name="DOI" value="10.17487/RFC4604"/>
        </reference>
        <reference anchor="RFC7576" target="https://www.rfc-editor.org/info/rfc7576"> anchor="RFC4607" target="https://www.rfc-editor.org/info/rfc4607" quoteTitle="true" derivedAnchor="RFC4607">
          <front>
          <title>General Gap Analysis
            <title>Source-Specific Multicast for Autonomic Networking</title>
          <seriesInfo name="DOI" value="10.17487/RFC7576"/>
          <seriesInfo name="RFC" value="7576"/> IP</title>
            <author initials="S." surname="Jiang" fullname="S. Jiang">
            <organization/> initials="H." surname="Holbrook" fullname="H. Holbrook">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="B." surname="Carpenter" surname="Cain" fullname="B. Carpenter">
            <organization/>
          </author>
          <author initials="M." surname="Behringer" fullname="M. Behringer">
            <organization/> Cain">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2015" month="June"/> year="2006" month="August"/>
            <abstract>
            <t>This document provides a problem statement
              <t indent="0">IP version 4 (IPv4) addresses in the 232/8 (232.0.0.0 to 232.255.255.255) range are designated as source-specific multicast (SSM) destination addresses and general gap analysis are reserved for an IP-based Autonomic Network that is mainly based on distributed network devices.  The document provides background use by reviewing the current status of autonomic aspects of IP networks and the extent to which current network management depends on centralization source-specific applications and human administrators.  Finally, protocols.  For IP version 6 (IPv6), the address prefix FF3x::/32 is reserved for source-specific multicast use.  This document outlines defines an extension to the general features that are missing from current Internet network abilities service that applies to datagrams sent to SSM addresses and are needed in the ideal Autonomic Network concept.</t>
            <t>This document is a product of defines the IRTF's Network Management Research Group.</t> host and router requirements to support this extension.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4607"/>
          <seriesInfo name="DOI" value="10.17487/RFC4607"/>
        </reference>
        <reference anchor="RFC7585" target="https://www.rfc-editor.org/info/rfc7585"> anchor="RFC4610" target="https://www.rfc-editor.org/info/rfc4610" quoteTitle="true" derivedAnchor="RFC4610">
          <front>
          <title>Dynamic Peer Discovery for RADIUS/TLS and RADIUS/DTLS Based on the Network Access Identifier (NAI)</title>
          <seriesInfo name="DOI" value="10.17487/RFC7585"/>
          <seriesInfo name="RFC" value="7585"/>
            <title>Anycast-RP Using Protocol Independent Multicast (PIM)</title>
            <author initials="S." surname="Winter" fullname="S. Winter">
            <organization/> initials="D." surname="Farinacci" fullname="D. Farinacci">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="M." surname="McCauley" fullname="M. McCauley">
            <organization/> initials="Y." surname="Cai" fullname="Y. Cai">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2015" month="October"/> year="2006" month="August"/>
            <abstract>
            <t>This document specifies a means
              <t indent="0">This specification allows Anycast-RP (Rendezvous Point) to find authoritative RADIUS servers for be used inside a given realm.  It is domain that runs Protocol Independent Multicast (PIM) only. Other multicast protocols (such as Multicast Source Discovery Protocol (MSDP), which has been used in conjunction with either RADIUS over Transport Layer Security (RADIUS/TLS) or RADIUS over Datagram Transport Layer Security (RADIUS/DTLS).</t> traditionally to solve this problem) are not required to support Anycast-RP.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4610"/>
          <seriesInfo name="DOI" value="10.17487/RFC4610"/>
        </reference>
        <reference anchor="RFC7721" target="https://www.rfc-editor.org/info/rfc7721"> anchor="RFC4985" target="https://www.rfc-editor.org/info/rfc4985" quoteTitle="true" derivedAnchor="RFC4985">
          <front>
          <title>Security and Privacy Considerations
            <title>Internet X.509 Public Key Infrastructure Subject Alternative Name for IPv6 Address Generation Mechanisms</title>
          <seriesInfo name="DOI" value="10.17487/RFC7721"/>
          <seriesInfo name="RFC" value="7721"/>
          <author initials="A." surname="Cooper" fullname="A. Cooper">
            <organization/>
          </author>
          <author initials="F." surname="Gont" fullname="F. Gont">
            <organization/>
          </author> Expression of Service Name</title>
            <author initials="D." surname="Thaler" fullname="D. Thaler">
            <organization/> initials="S." surname="Santesson" fullname="S. Santesson">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2016" month="March"/> year="2007" month="August"/>
            <abstract>
            <t>This
              <t indent="0">This document discusses privacy and security considerations defines a new name form for several IPv6 address generation mechanisms, both standardized and non-standardized.  It evaluates how different mechanisms mitigate different threats and inclusion in the trade-offs otherName field of an X.509 Subject Alternative Name extension that implementors, developers, allows a certificate subject to be associated with the service name and users face in choosing different addresses or address generation mechanisms.</t> domain name components of a DNS Service Resource Record.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4985"/>
          <seriesInfo name="DOI" value="10.17487/RFC4985"/>
        </reference>
        <reference anchor="RFC7761" target="https://www.rfc-editor.org/info/rfc7761"> anchor="RFC5790" target="https://www.rfc-editor.org/info/rfc5790" quoteTitle="true" derivedAnchor="RFC5790">
          <front>
          <title>Protocol Independent Multicast - Sparse Mode (PIM-SM):
            <title>Lightweight Internet Group Management Protocol Specification (Revised)</title>
          <seriesInfo name="DOI" value="10.17487/RFC7761"/>
          <seriesInfo name="RFC" value="7761"/>
          <seriesInfo name="STD" value="83"/>
          <author initials="B." surname="Fenner" fullname="B. Fenner">
            <organization/>
          </author>
          <author initials="M." surname="Handley" fullname="M. Handley">
            <organization/>
          </author> Version 3 (IGMPv3) and Multicast Listener Discovery Version 2 (MLDv2) Protocols</title>
            <author initials="H." surname="Holbrook" surname="Liu" fullname="H. Holbrook">
            <organization/>
          </author>
          <author initials="I." surname="Kouvelas" fullname="I. Kouvelas">
            <organization/>
          </author>
          <author initials="R." surname="Parekh" fullname="R. Parekh">
            <organization/> Liu">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="Z." surname="Zhang" fullname="Z. Zhang">
            <organization/> initials="W." surname="Cao" fullname="W. Cao">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="L." surname="Zheng" fullname="L. Zheng">
            <organization/> initials="H." surname="Asaeda" fullname="H. Asaeda">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2016" month="March"/> year="2010" month="February"/>
            <abstract>
            <t>This
              <t indent="0">This document specifies Protocol Independent Multicast - Sparse Mode (PIM-SM).  PIM-SM is a multicast routing protocol that can use the underlying unicast routing information base or a separate multicast-capable routing information base.  It builds unidirectional shared trees rooted at a Rendezvous Point (RP) per group, describes lightweight IGMPv3 and it optionally creates shortest-path trees per source.</t>
            <t>This document obsoletes RFC 4601 by replacing it, addresses the errata filed against it, removes MLDv2 protocols (LW- IGMPv3 and LW-MLDv2), which simplify the optional (*,*,RP), PIM Multicast Border Router features standard (full) versions of IGMPv3 and authentication using IPsec that lack sufficient deployment experience (see Appendix A), MLDv2.  The interoperability with the full versions and moves the PIM specification to Internet Standard.</t> previous versions of IGMP and MLD is also taken into account.   [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="5790"/>
          <seriesInfo name="DOI" value="10.17487/RFC5790"/>
        </reference>
        <reference anchor="RFC7950" target="https://www.rfc-editor.org/info/rfc7950"> anchor="RFC5880" target="https://www.rfc-editor.org/info/rfc5880" quoteTitle="true" derivedAnchor="RFC5880">
          <front>
          <title>The YANG 1.1 Data Modeling Language</title>
          <seriesInfo name="DOI" value="10.17487/RFC7950"/>
          <seriesInfo name="RFC" value="7950"/>
            <title>Bidirectional Forwarding Detection (BFD)</title>
            <author initials="M." surname="Bjorklund" fullname="M. Bjorklund" role="editor">
            <organization/> initials="D." surname="Katz" fullname="D. Katz">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="D." surname="Ward" fullname="D. Ward">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2016" month="August"/> year="2010" month="June"/>
            <abstract>
            <t>YANG is a data modeling language used to model configuration data, state data, Remote Procedure Calls, and notifications for network management protocols.  This
              <t indent="0">This document describes the syntax and semantics of version 1.1 of the YANG language.  YANG version 1.1 is a maintenance release of the YANG language, addressing ambiguities and defects protocol intended to detect faults in the original specification.  There are a small number of backward incompatibilities from YANG version 1.  This document also specifies the YANG mappings bidirectional path between two forwarding engines, including interfaces, data link(s), and to the Network Configuration Protocol (NETCONF).</t> extent possible the forwarding engines themselves, with potentially very low latency.  It operates independently of media, data protocols, and routing protocols. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="5880"/>
          <seriesInfo name="DOI" value="10.17487/RFC5880"/>
        </reference>
        <reference anchor="RFC8028" target="https://www.rfc-editor.org/info/rfc8028"> anchor="RFC5905" target="https://www.rfc-editor.org/info/rfc5905" quoteTitle="true" derivedAnchor="RFC5905">
          <front>
          <title>First-Hop Router Selection by Hosts in a Multi-Prefix Network</title>
          <seriesInfo name="DOI" value="10.17487/RFC8028"/>
          <seriesInfo name="RFC" value="8028"/>
            <title>Network Time Protocol Version 4: Protocol and Algorithms Specification</title>
            <author initials="F." surname="Baker" fullname="F. Baker">
            <organization/> initials="D." surname="Mills" fullname="D. Mills">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="B." surname="Carpenter" fullname="B. Carpenter">
            <organization/> initials="J." surname="Martin" fullname="J. Martin" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="J." surname="Burbank" fullname="J. Burbank">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="W." surname="Kasch" fullname="W. Kasch">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2016" month="November"/> year="2010" month="June"/>
            <abstract>
            <t>This document describes expected IPv6 host behavior in a scenario that has more than one prefix, each allocated by an upstream network that is assumed to implement BCP 38 ingress filtering, when the host has multiple routers to choose from.  It also applies to other scenarios such as the usage of stateful firewalls that effectively act as address-based filters.  Host behavior
              <t indent="0">The Network Time Protocol (NTP) is widely used to synchronize computer clocks in choosing a first-hop router may interact the Internet.  This document describes NTP version 4 (NTPv4), which is backwards compatible with source address selection NTP version 3 (NTPv3), described in a given implementation.  However, the selection RFC 1305, as well as previous versions of the source address for protocol. NTPv4 includes a packet is done before the first-hop router for that packet is chosen. Given that the network or host is, or appears modified protocol header to be, multihomed with multiple provider-allocated addresses, that accommodate the host has elected to use a source Internet Protocol version 6 address family.  NTPv4 includes fundamental improvements in a given prefix, the mitigation and discipline algorithms that some but not all neighboring routers are advertising that prefix in their Router Advertisement Prefix Information Options, this document specifies extend the potential accuracy to which router the tens of microseconds with modern workstations and fast LANs.  It includes a host should present its transmission. dynamic server discovery scheme, so that in many cases, specific server configuration is not required.  It updates RFC 4861.</t> corrects certain errors in the NTPv3 design and implementation and includes an optional extension mechanism.   [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="5905"/>
          <seriesInfo name="DOI" value="10.17487/RFC5905"/>
        </reference>
        <reference anchor="RFC8126" target="https://www.rfc-editor.org/info/rfc8126"> anchor="RFC5912" target="https://www.rfc-editor.org/info/rfc5912" quoteTitle="true" derivedAnchor="RFC5912">
          <front>
          <title>Guidelines
            <title>New ASN.1 Modules for Writing an IANA Considerations Section in RFCs</title>
          <seriesInfo name="DOI" value="10.17487/RFC8126"/>
          <seriesInfo name="RFC" value="8126"/>
          <seriesInfo name="BCP" value="26"/>
          <author initials="M." surname="Cotton" fullname="M. Cotton">
            <organization/>
          </author> the Public Key Infrastructure Using X.509 (PKIX)</title>
            <author initials="B." surname="Leiba" fullname="B. Leiba">
            <organization/> initials="P." surname="Hoffman" fullname="P. Hoffman">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="T." surname="Narten" fullname="T. Narten">
            <organization/> initials="J." surname="Schaad" fullname="J. Schaad">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2017" year="2010" month="June"/>
            <abstract>
            <t>Many protocols make use of points of extensibility that use constants to identify various protocol parameters.  To ensure that the values in these fields do not have conflicting uses
              <t indent="0">The Public Key Infrastructure using X.509 (PKIX) certificate format, and to promote interoperability, their allocations many associated formats, are often coordinated by a central record keeper.  For IETF protocols, that role is filled by the Internet Assigned Numbers Authority (IANA).</t>
            <t>To make assignments in a given registry prudently, guidance describing the conditions under which new values should be assigned, as well as when and how modifications expressed using ASN.1.  The current ASN.1 modules conform to existing values can be made, is needed. the 1988 version of ASN.1.  This document defines a framework for updates those ASN.1 modules to conform to the documentation 2002 version of these guidelines by specification authors, in order ASN.1. There are no bits-on-the-wire changes to assure that any of the provided guidance for formats; this is simply a change to the IANA Considerations syntax.  This document is clear not an Internet  Standards Track specification; it is published for informational  purposes.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="5912"/>
          <seriesInfo name="DOI" value="10.17487/RFC5912"/>
        </reference>
        <reference anchor="RFC6120" target="https://www.rfc-editor.org/info/rfc6120" quoteTitle="true" derivedAnchor="RFC6120">
          <front>
            <title>Extensible Messaging and addresses Presence Protocol (XMPP): Core</title>
            <author initials="P." surname="Saint-Andre" fullname="P. Saint-Andre">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2011" month="March"/>
            <abstract>
              <t indent="0">The Extensible Messaging and Presence Protocol (XMPP) is an application profile of the various issues Extensible Markup Language (XML) that are likely in enables the operation near-real-time exchange of a registry.</t>
            <t>This is the third edition structured yet extensible data between any two or more network entities.  This document defines XMPP's core protocol methods: setup and teardown of this document; it XML streams, channel encryption, authentication, error handling, and communication primitives for messaging, network availability ("presence"), and request-response interactions.  This document obsoletes RFC 5226.</t> 3920.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6120"/>
          <seriesInfo name="DOI" value="10.17487/RFC6120"/>
        </reference>
        <reference anchor="RFC8366" target="https://www.rfc-editor.org/info/rfc8366"> anchor="RFC6241" target="https://www.rfc-editor.org/info/rfc6241" quoteTitle="true" derivedAnchor="RFC6241">
          <front>
          <title>A Voucher Artifact for Bootstrapping Protocols</title>
          <seriesInfo name="DOI" value="10.17487/RFC8366"/>
          <seriesInfo name="RFC" value="8366"/>
            <title>Network Configuration Protocol (NETCONF)</title>
            <author initials="K." surname="Watsen" fullname="K. Watsen">
            <organization/> initials="R." surname="Enns" fullname="R. Enns" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="M." surname="Richardson" surname="Bjorklund" fullname="M. Richardson">
            <organization/> Bjorklund" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="M." surname="Pritikin" fullname="M. Pritikin">
            <organization/> initials="J." surname="Schoenwaelder" fullname="J. Schoenwaelder" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="T." surname="Eckert" fullname="T. Eckert">
            <organization/> initials="A." surname="Bierman" fullname="A. Bierman" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2018" month="May"/> year="2011" month="June"/>
            <abstract>
            <t>This
              <t indent="0">The Network Configuration Protocol (NETCONF) defined in this document defines a strategy to securely assign a pledge provides mechanisms to install, manipulate, and delete the configuration of network devices.  It uses an owner using an artifact signed, directly or indirectly, by Extensible Markup Language (XML)-based data encoding for the pledge's manufacturer.  This artifact is known configuration data as a "voucher".</t>
            <t>This document defines an artifact format well as a YANG-defined JSON document that has been signed using a Cryptographic Message Syntax (CMS) structure.  Other YANG-derived formats are possible.  The voucher artifact is normally generated by the pledge's manufacturer (i.e., the Manufacturer Authorized Signing Authority (MASA).</t>
            <t>This protocol messages.  The NETCONF protocol operations are realized as remote procedure calls (RPCs).  This document only defines the voucher artifact, leaving it to other documents to describe specialized protocols for accessing it.</t> obsoletes RFC 4741.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6241"/>
          <seriesInfo name="DOI" value="10.17487/RFC6241"/>
        </reference>
        <reference anchor="RFC8316" target="https://www.rfc-editor.org/info/rfc8316"> anchor="RFC6335" target="https://www.rfc-editor.org/info/rfc6335" quoteTitle="true" derivedAnchor="RFC6335">
          <front>
          <title>Autonomic Networking Use Case
            <title>Internet Assigned Numbers Authority (IANA) Procedures for Distributed Detection the Management of the Service Level Agreement (SLA) Violations</title>
          <seriesInfo name="DOI" value="10.17487/RFC8316"/>
          <seriesInfo name="RFC" value="8316"/> Name and Transport Protocol Port Number Registry</title>
            <author initials="J." surname="Nobre" fullname="J. Nobre">
            <organization/> initials="M." surname="Cotton" fullname="M. Cotton">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="L." surname="Granville" surname="Eggert" fullname="L. Granville">
            <organization/> Eggert">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="A." surname="Clemm" fullname="A. Clemm">
            <organization/> initials="J." surname="Touch" fullname="J. Touch">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="A." surname="Gonzalez Prieto" fullname="A. Gonzalez Prieto">
            <organization/> initials="M." surname="Westerlund" fullname="M. Westerlund">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="S." surname="Cheshire" fullname="S. Cheshire">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2018" month="February"/> year="2011" month="August"/>
            <abstract>
            <t>This
              <t indent="0">This document describes an experimental use case that employs autonomic networking for the monitoring of Service Level Agreements (SLAs).  The use case is for detecting violations of SLAs in a distributed fashion.  It strives to optimize and dynamically adapt defines the autonomic deployment of active measurement probes in a way procedures that maximizes the likelihood of detecting service-level violations with a given resource budget to perform active measurements.  This optimization Internet Assigned Numbers Authority (IANA) uses when handling assignment and adaptation should be done without any outside guidance or intervention.</t>
            <t>This document is a product of other requests related to the IRTF Network Management Research Group (NMRG). Service Name and Transport Protocol Port Number registry.  It is published for informational purposes.</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="RFC8368" target="https://www.rfc-editor.org/info/rfc8368">
        <front>
          <title>Using an Autonomic Control Plane for Stable Connectivity of Network Operations, Administration, also discusses the rationale and Maintenance (OAM)</title>
          <seriesInfo name="DOI" value="10.17487/RFC8368"/>
          <seriesInfo name="RFC" value="8368"/>
          <author initials="T." surname="Eckert" fullname="T. Eckert" role="editor">
            <organization/>
          </author>
          <author initials="M." surname="Behringer" fullname="M. Behringer">
            <organization/>
          </author>
          <date year="2018" month="May"/>
          <abstract>
            <t>Operations, Administration, principles behind these procedures and Maintenance (OAM), as per BCP 161, for data networks is often subject to how they facilitate the problem long-term sustainability of circular dependencies when relying on connectivity provided by the network to be managed for registry.</t>
              <t indent="0">This document updates IANA's procedures by obsoleting the OAM purposes.</t>
            <t>Provisioning while bringing up devices previous UDP and networks tends to be more difficult to automate than service provisioning later on.  Changes TCP port assignment procedures defined in core network functions impacting reachability cannot be automated because Sections 8 and 9.1 of ongoing connectivity requirements the IANA Allocation Guidelines, and it updates the IANA service name and port assignment procedures for UDP-Lite, the OAM equipment itself, Datagram Congestion Control Protocol (DCCP), and widely used OAM protocols are not secure enough to be carried across the network without security concerns.</t>
            <t>This document describes how to integrate OAM processes with an autonomic control plane in order Stream Control Transmission Protocol (SCTP).  It also updates the DNS SRV specification to provide stable clarify what a service name is and secure connectivity for those OAM processes.  This connectivity how it is not subject to the aforementioned circular dependencies.</t> registered.  This memo documents an Internet Best Current Practice.</t>
            </abstract>
          </front>
      </reference>
      <reference anchor="RFC8398" target="https://www.rfc-editor.org/info/rfc8398">
        <front>
          <title>Internationalized Email Addresses in X.509 Certificates</title>
          <seriesInfo name="DOI" value="10.17487/RFC8398"/> name="BCP" value="165"/>
          <seriesInfo name="RFC" value="8398"/>
          <author initials="A." surname="Melnikov" fullname="A. Melnikov" role="editor">
            <organization/>
          </author> value="6335"/>
          <seriesInfo name="DOI" value="10.17487/RFC6335"/>
        </reference>
        <reference anchor="RFC6402" target="https://www.rfc-editor.org/info/rfc6402" quoteTitle="true" derivedAnchor="RFC6402">
          <front>
            <title>Certificate Management over CMS (CMC) Updates</title>
            <author initials="W." surname="Chuang" fullname="W. Chuang" role="editor">
            <organization/> initials="J." surname="Schaad" fullname="J. Schaad">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2018" month="May"/> year="2011" month="November"/>
            <abstract>
            <t>This
              <t indent="0">This document defines contains a set of updates to the base syntax for CMC, a Certificate Management protocol using the Cryptographic Message Syntax (CMS).  This document updates RFC 5272, RFC 5273, and RFC 5274.</t>
              <t indent="0">The new name form items in this document are: new controls for inclusion future work in the otherName field doing server side key generation, definition of an X.509 a Subject Alternative Name Information Access value to identify CMC servers, and Issuer Alternative Name extension that allows the registration of a certificate subject port number for TCP/IP for the CMC service to be associated with an internationalized email address.</t>
            <t>This document updates RFC 5280.</t> run on.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6402"/>
          <seriesInfo name="DOI" value="10.17487/RFC6402"/>
        </reference>
        <reference anchor="RFC8402" target="https://www.rfc-editor.org/info/rfc8402"> anchor="RFC6407" target="https://www.rfc-editor.org/info/rfc6407" quoteTitle="true" derivedAnchor="RFC6407">
          <front>
          <title>Segment Routing Architecture</title>
          <seriesInfo name="DOI" value="10.17487/RFC8402"/>
          <seriesInfo name="RFC" value="8402"/>
          <author initials="C." surname="Filsfils" fullname="C. Filsfils" role="editor">
            <organization/>
          </author>
          <author initials="S." surname="Previdi" fullname="S. Previdi" role="editor">
            <organization/>
          </author>
          <author initials="L." surname="Ginsberg" fullname="L. Ginsberg">
            <organization/>
          </author>
            <title>The Group Domain of Interpretation</title>
            <author initials="B." surname="Decraene" surname="Weis" fullname="B. Decraene">
            <organization/> Weis">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="S." surname="Litkowski" surname="Rowles" fullname="S. Litkowski">
            <organization/> Rowles">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="R." surname="Shakir" fullname="R. Shakir">
            <organization/> initials="T." surname="Hardjono" fullname="T. Hardjono">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2018" month="July"/> year="2011" month="October"/>
            <abstract>
            <t>Segment Routing (SR) leverages the source routing paradigm.  A node steers a packet through an ordered list of instructions, called "segments".  A segment can represent any instruction, topological or service based.  A segment can have a semantic local to an SR node or global within an SR domain.  SR provides a mechanism that allows a flow to be restricted to a specific topological path, while maintaining per-flow state only at the ingress node(s) to the SR domain.</t>
            <t>SR can be directly applied to the MPLS architecture with no change to the forwarding plane.  A segment is encoded as an MPLS label.  An ordered list of segments is encoded as a stack of labels.  The segment to process is on the top of the stack.  Upon completion of a segment, the related label is popped from the stack.</t>
            <t>SR can be applied to
              <t indent="0">This document describes the IPv6 architecture, with a new type of routing header.  A segment is encoded as an IPv6 address.  An ordered list of segments is encoded as an ordered list Group Domain of IPv6 addresses Interpretation (GDOI) protocol specified in RFC 3547.  The GDOI provides group key management to support secure group communications according to the routing header.  The active segment is indicated by the Destination Address (DA) of the packet. architecture specified in RFC 4046.  The next active segment is indicated GDOI manages group security associations, which are used by a pointer in the new routing header.</t> IPsec and potentially other data security protocols.  This document replaces RFC 3547.   [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6407"/>
          <seriesInfo name="DOI" value="10.17487/RFC6407"/>
        </reference>
        <reference anchor="RFC8572" target="https://www.rfc-editor.org/info/rfc8572"> anchor="RFC6554" target="https://www.rfc-editor.org/info/rfc6554" quoteTitle="true" derivedAnchor="RFC6554">
          <front>
          <title>Secure Zero Touch Provisioning (SZTP)</title>
          <seriesInfo name="DOI" value="10.17487/RFC8572"/>
          <seriesInfo name="RFC" value="8572"/>
            <title>An IPv6 Routing Header for Source Routes with the Routing Protocol for Low-Power and Lossy Networks (RPL)</title>
            <author initials="K." surname="Watsen" fullname="K. Watsen">
            <organization/> initials="J." surname="Hui" fullname="J. Hui">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="I." surname="Farrer" fullname="I. Farrer">
            <organization/> initials="JP." surname="Vasseur" fullname="JP. Vasseur">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="M." surname="Abrahamsson" fullname="M. Abrahamsson">
            <organization/> initials="D." surname="Culler" fullname="D. Culler">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="V." surname="Manral" fullname="V. Manral">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2019" month="April"/> year="2012" month="March"/>
            <abstract>
            <t>This document presents a technique
              <t indent="0">In Low-Power and Lossy Networks (LLNs), memory constraints on routers may limit them to securely provision maintaining, at most, a networking device when few routes.  In some configurations, it is booting in a factory-default state.  Variations in the solution enable it necessary to use these memory-constrained routers to deliver datagrams to nodes within the LLN.  The Routing Protocol for Low-Power and Lossy Networks (RPL) can be used on both public and private networks.  The provisioning steps are able in some deployments to update store most, if not all, routes on one (e.g., the boot image, commit an initial configuration, Directed Acyclic Graph (DAG) root) or a few routers and execute arbitrary scripts to address auxiliary needs.  The updated device is subsequently able forward the IPv6 datagram using a source routing technique to establish secure connections with other systems.  For instance, avoid large routing tables on memory-constrained routers.  This document specifies a device may establish NETCONF (RFC 6241) and/or RESTCONF (RFC 8040) connections with deployment-specific network management systems.</t> new IPv6 Routing header type for delivering datagrams within a RPL routing domain.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6554"/>
          <seriesInfo name="DOI" value="10.17487/RFC6554"/>
        </reference>
        <reference anchor="I-D.ietf-anima-reference-model" target="http://www.ietf.org/internet-drafts/draft-ietf-anima-reference-model-10.txt"> anchor="RFC6724" target="https://www.rfc-editor.org/info/rfc6724" quoteTitle="true" derivedAnchor="RFC6724">
          <front>
          <title>A Reference Model
            <title>Default Address Selection for Autonomic Networking</title>
          <seriesInfo name="Internet-Draft" value="draft-ietf-anima-reference-model-10"/>
          <author initials="M" surname="Behringer" fullname="Michael Behringer">
            <organization/>
          </author> Internet Protocol Version 6 (IPv6)</title>
            <author initials="B" surname="Carpenter" fullname="Brian Carpenter">
            <organization/> initials="D." surname="Thaler" fullname="D. Thaler" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="T" surname="Eckert" fullname="Toerless Eckert">
            <organization/> initials="R." surname="Draves" fullname="R. Draves">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="L" surname="Ciavaglia" fullname="Laurent Ciavaglia">
            <organization/> initials="A." surname="Matsumoto" fullname="A. Matsumoto">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="J" surname="Nobre" fullname="Jeferson Nobre">
            <organization/> initials="T." surname="Chown" fullname="T. Chown">
              <organization showOnFrontPage="true"/>
            </author>
            <date month="November" day="22" year="2018"/> year="2012" month="September"/>
            <abstract>
            <t>This
              <t indent="0">This document describes a reference model two algorithms, one for Autonomic Networking source address selection and one for managed networks.  It defines destination address selection.  The algorithms specify default behavior for all Internet Protocol version 6 (IPv6) implementations.  They do not override choices made by applications or upper-layer protocols, nor do they preclude the behaviour development of more advanced mechanisms for address selection.  The two algorithms share a common context, including an autonomic node, how the various elements in an autonomic context work together, and how autonomic services can use the infrastructure.</t>
          </abstract>
        </front>
      </reference>
      <reference anchor="I-D.eckert-anima-noc-autoconfig" target="http://www.ietf.org/internet-drafts/draft-eckert-anima-noc-autoconfig-00.txt">
        <front>
          <title>Autoconfiguration of NOC services in ACP networks via GRASP</title>
          <seriesInfo name="Internet-Draft" value="draft-eckert-anima-noc-autoconfig-00"/>
          <author initials="T" surname="Eckert" fullname="Toerless Eckert">
            <organization/>
          </author>
          <date month="July" day="2" year="2018"/>
          <abstract>
            <t>This document defines standards optional mechanism for the autoconfiguration of crucial NOC services on ACP nodes via GRASP.  It enables secure remote access allowing administrators to zero-touch bootstrapped ANI devices via SSH/NETCONF with RADIUS/Diameter authentication and authorization provide policy that can override the default behavior.  In dual-stack implementations, the destination address selection algorithm can consider both IPv4 and provides lifecycle autoconfiguration for other crucial services such IPv6 addresses -- depending on the available source addresses, the algorithm might prefer IPv6 addresses over IPv4 addresses, or vice versa.</t>
              <t indent="0">Default address selection as syslog, NTP (clock synchronization) defined in this specification applies to all IPv6 nodes, including both hosts and DNS for operational purposes.</t> routers.  This document obsoletes RFC 3484.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6724"/>
          <seriesInfo name="DOI" value="10.17487/RFC6724"/>
        </reference>
        <reference anchor="IEEE-1588-2008" target="http://standards.ieee.org/findstds/standard/1588-2008.html"> anchor="RFC6733" target="https://www.rfc-editor.org/info/rfc6733" quoteTitle="true" derivedAnchor="RFC6733">
          <front>
          <title>
                            IEEE Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems
                            </title>
            <title>Diameter Base Protocol</title>
            <author fullname="IEEE">
            <organization>IEEE Standards Board</organization> initials="V." surname="Fajardo" fullname="V. Fajardo" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
          <date month="December" year="2008"/>
        </front>
      </reference>
      <reference anchor="AR8021" target="http://standards.ieee.org/findstds/standard/802.1AR-2009.html">
        <front>
          <title>
                            IEEE Standard for Local and metropolitan area networks - Secure Device Identity
                            </title>
            <author fullname="WG802.1 - Higher Layer LAN Protocols Working Group">
            <organization>IEEE SA-Standards Board</organization> initials="J." surname="Arkko" fullname="J. Arkko">
              <organization showOnFrontPage="true"/>
            </author>
          <date month="December" year="2009"/>
        </front>
      </reference>
      <reference anchor="IEEE-802.1X" target="http://standards.ieee.org/findstds/standard/802.1X-2010.html">
        <front>
          <title>
                            IEEE Standard for Local and Metropolitan Area Networks: Port-Based Network Access Control
                            </title>
            <author fullname="WG802.1 - Higher Layer LAN Protocols Working Group">
            <organization>IEEE SA-Standards Board</organization> initials="J." surname="Loughney" fullname="J. Loughney">
              <organization showOnFrontPage="true"/>
            </author>
          <date month="February" year="2010"/>
        </front>
      </reference>
      <reference anchor="MACSEC" target="https://standards.ieee.org/findstds/standard/802.1AE-2006.html">
        <front>
          <title>
                            IEEE Standard for Local and Metropolitan Area Networks: Media Access Control (MAC) Security
                            </title>
            <author fullname="WG802.1 - Higher Layer LAN Protocols Working Group">
            <organization>IEEE SA-Standards Board</organization> initials="G." surname="Zorn" fullname="G. Zorn" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <date month="June" year="2006"/>
        </front>
      </reference>
      <reference anchor="LLDP" target="https://standards.ieee.org/findstds/standard/802.1AB-2016.html">
        <front>
          <title>
                            IEEE Standard year="2012" month="October"/>
            <abstract>
              <t indent="0">The Diameter base protocol is intended to provide an Authentication, Authorization, and Accounting (AAA) framework for Local applications such as network access or IP mobility in both local and Metropolitan Area Networks: Station roaming situations.  This document specifies the message format, transport, error reporting, accounting, and Media Access Control Connectivity Discovery
                            </title>
          <author fullname="WG802.1 - Higher Layer LAN Protocols Working Group">
            <organization>IEEE SA-Standards Board</organization>
          </author>
          <date month="June" year="2016"/>
        </front>
      </reference>
      <reference anchor="CABFORUM" target="https://cabforum.org/baseline-requirements-certificate-contents/">
        <front>
          <title>
                                Certificate Contents for Baseline SSL
                            </title>
          <author>
            <organization>CA/Browser Forum</organization>
          </author>
          <date month="Nov" year="2019"/>
        </front>
      </reference>

      <reference anchor="X.509" target="https://www.itu.int/rec/T-REC-X.509">
        <front>
          <title>Information technology - Open Systems Interconnection - security services used by all Diameter applications.  The Directory: Public-key Diameter base protocol as defined in this document obsoletes RFC 3588 and attribute certificate frameworks</title>
          <seriesInfo name="ITU-T Recommendation X.509," value="ISO/IEC 9594-8"/>
          <author>
            <organization>International Telecommunication Union</organization>
          </author>
          <date month="October" year="2016"/> RFC 5719, and it must be supported by all new Diameter implementations.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
      </reference>

      <reference anchor="X.520" target="https://www.itu.int/rec/T-REC-X.520">
        <front>
          <title>Information technology - Open Systems Interconnection - The Directory: Selected attribute types</title>
          <seriesInfo name="ITU-T Recommendation X.520," value="ISO/IEC 9594-6"/>
          <author>
            <organization>International Telecommunication Union</organization>
          </author>
          <date month="October" year="2016"/>
        </front> name="RFC" value="6733"/>
          <seriesInfo name="DOI" value="10.17487/RFC6733"/>
        </reference>
        <reference anchor="ACPDRAFT"  target="https://tools.ietf.org/html/draft-ietf-anima-autonomic-control-plane-30.pdf"> anchor="RFC6762" target="https://www.rfc-editor.org/info/rfc6762" quoteTitle="true" derivedAnchor="RFC6762">
          <front>
            <title>An Autonomic Control Plane (ACP)</title>
            <seriesInfo name="Internet-Draft" value="draft-ietf-anima-autonomic-control-plane-30"/>
            <author initials="T" surname="Eckert" fullname="Toerless Eckert">
              <organization/>
            </author>
            <title>Multicast DNS</title>
            <author initials="M" surname="Behringer" fullname="Michael Behringer">
              <organization/> initials="S." surname="Cheshire" fullname="S. Cheshire">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="S" surname="Bjarnason" fullname="Steinthor Bjarnason">
              <organization/> initials="M." surname="Krochmal" fullname="M. Krochmal">
              <organization showOnFrontPage="true"/>
            </author>
          </front>
          <annotation>[RFC-Editor: Please remove this complete reference from
            <date year="2013" month="February"/>
            <abstract>
              <t indent="0">As networked devices become smaller, more portable, and more ubiquitous, the RFC] Refer ability to operate with less configured infrastructure is increasingly important.  In particular, the IETF working group draft for ability to look up DNS resource record data types (including, but not limited to, host names) in the few sections removed from this document for various reasons. They capture absence of a conventional managed DNS server is useful.</t>
              <t indent="0">Multicast DNS (mDNS) provides the state ability to perform DNS-like operations on the local link in the absence of discussion about unresolved issues that may need any conventional Unicast DNS server.  In addition, Multicast DNS designates a portion of the DNS namespace to be revisited in future work.
          </annotation>
        </reference>

      <reference anchor="FCC" target="https://docs.fcc.gov/public/attachments/DOC-367699A1.docx">
        <front>
          <title>FCC STAFF REPORT ON NATIONWIDE T-MOBILE NETWORK OUTAGE ON JUNE 15, 2020 (PS Docket No. 20-183)</title>
          <author>
            <organization>FCC</organization>
          </author>
          <date year="2020" />
        </front>
        <annotation>The FCC's Public Safety free for local use, without the need to pay any annual fee, and Homeland Security Bureau issues a report on without the need to set up delegations or otherwise configure a nationwide T-Mobile outage conventional DNS server to answer for those names.</t>
              <t indent="0">The primary benefits of Multicast DNS names are that occurred on June 15, 2020. Action by: Public Safety (i) they require little or no administration or configuration to set them up, (ii) they work when no infrastructure is present, and Homeland Security Bureau.</annotation> (iii) they work during infrastructure failures.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6762"/>
          <seriesInfo name="DOI" value="10.17487/RFC6762"/>
        </reference>
        <reference anchor="I-D.ietf-roll-applicability-template" target="http://www.ietf.org/internet-drafts/draft-ietf-roll-applicability-template-09.txt"> anchor="RFC6763" target="https://www.rfc-editor.org/info/rfc6763" quoteTitle="true" derivedAnchor="RFC6763">
          <front>
          <title>ROLL Applicability Statement Template</title>
          <seriesInfo name="Internet-Draft" value="draft-ietf-roll-applicability-template-09"/>
            <title>DNS-Based Service Discovery</title>
            <author initials="M" surname="Richardson" fullname="Michael Richardson">
            <organization/> initials="S." surname="Cheshire" fullname="S. Cheshire">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="M." surname="Krochmal" fullname="M. Krochmal">
              <organization showOnFrontPage="true"/>
            </author>
            <date month="May" day="3" year="2016"/> year="2013" month="February"/>
            <abstract>
            <t>This
              <t indent="0">This document is a template applicability statement for the Routing over Low-power specifies how DNS resource records are named and Lossy Networks (ROLL) WG.  This document is not for publication, but rather is structured to be used as facilitate service discovery.  Given a template.</t>
          </abstract>
        </front>
      </reference>
    </references>
    <section anchor="further" numbered="true" toc="default">
      <name>Background and Futures (Informative)</name>
      <t>The following sections discuss additional background information about aspects of the normative parts of this document or associated mechanisms such as BRSKI (such as why specific choices were made by the ACP) and they provide discussion about possible future variations type of the ACP.</t>
      <section anchor="address-spaces" numbered="true" toc="default">
        <name>ACP Address Space Schemes</name>
        <t>This document defines the Zone, Vlong service that a client is looking for, and Manual sub
address schemes primarily to support address prefix assignment
via distributed, potentially uncoordinated ACP registrars as defined a domain in <xref target="acp-registrars" format="default"/>. This
costs 48/46-bit identifier so which the client is looking for that these ACP registrar can assign
non-conflicting address prefixes. This design does not leave enough
bits service, this mechanism allows clients to simultaneously support a large number of nodes (Node-ID)
plus discover a large prefix list of local addresses for every node plus a
large enough set named instances of bits to identify a routing Zone. In result,
Zone, Vlong 8/16 attempt to support all features, but via
separate prefixes.</t>
        <t>In networks that always expect desired service, using standard DNS queries. This mechanism is referred to rely on a centralized PMS as described above (<xref target="pms" format="default"/>), the 48/46-bits DNS-based Service Discovery, or DNS-SD.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6763"/>
          <seriesInfo name="DOI" value="10.17487/RFC6763"/>
        </reference>
        <reference anchor="RFC6824" target="https://www.rfc-editor.org/info/rfc6824" quoteTitle="true" derivedAnchor="RFC6824">
          <front>
            <title>TCP Extensions for
the Registrar-ID could be saved. Such variations of the ACP
addressing mechanisms could be introduced through future work
in different ways. If Multipath Operation with Multiple Addresses</title>
            <author initials="A." surname="Ford" fullname="A. Ford">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="C." surname="Raiciu" fullname="C. Raiciu">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="M." surname="Handley" fullname="M. Handley">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="O." surname="Bonaventure" fullname="O. Bonaventure">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2013" month="January"/>
            <abstract>
              <t indent="0">TCP/IP communication is currently restricted to a new otherName was introduced,
incompatible ACP variations could be created
where every design aspect single path per connection, yet multiple paths often exist between peers.  The simultaneous use of the ACP could be changed. Including
all addressing choices. If instead these multiple paths for a new addressing sub-type TCP/IP session would be defined, it could be a backward compatible extension
of this ACP specification. Information such as improve resource usage within the size of network and, thus, improve user experience through higher throughput and improved resilience to network failure.</t>
              <t indent="0">Multipath TCP provides the ability to simultaneously use multiple paths between peers.  This document presents a
zone-prefix and the length set of the prefix assigned extensions to traditional TCP to support multipath operation.  The protocol offers the ACP
node itself could be encoded via the extension field same type of service to applications as TCP (i.e., reliable bytestream), and it provides the
acp-node-name.</t>
        <t>Note that an explicitly defined "Manual" addressing sub-scheme
is always beneficial components necessary to provide establish and use multiple TCP flows across potentially disjoint paths.  This  document defines an easy way Experimental Protocol for ACP nodes to prohibit
incorrect manual configuration of any non-"Manual" ACP address spaces
and therefore ensure the Internet community.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6824"/>
          <seriesInfo name="DOI" value="10.17487/RFC6824"/>
        </reference>
        <reference anchor="RFC6830" target="https://www.rfc-editor.org/info/rfc6830" quoteTitle="true" derivedAnchor="RFC6830">
          <front>
            <title>The Locator/ID Separation Protocol (LISP)</title>
            <author initials="D." surname="Farinacci" fullname="D. Farinacci">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="V." surname="Fuller" fullname="V. Fuller">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="D." surname="Meyer" fullname="D. Meyer">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="D." surname="Lewis" fullname="D. Lewis">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2013" month="January"/>
            <abstract>
              <t indent="0">This document describes a network-layer-based protocol that "Manual" operations will never impact
correct routing for any non-"Manual" ACP enables separation of IP addresses assigned via
ACP certificates.</t>
      </section>
      <section anchor="bootstrap" numbered="true" toc="default">
        <name>BRSKI Bootstrap (ANI)</name>
        <t>BRSKI describes how nodes with an IDevID certificate can securely into two new numbering spaces: Endpoint Identifiers (EIDs) and zero-touch enroll with an LDevID certificate Routing Locators (RLOCs).  No changes are required to support the ACP.  BRSKI also leverages the ACP either host protocol stacks or to enable zero-touch bootstrap the "core" of new nodes across networks without any configuration requirements across the transit nodes (e.g., no DHCP/DNS forwarding/server setup).  This includes otherwise not configured networks as described in <xref target="secure-bootstrap" format="default"/>.  Therefore, BRSKI in conjunction with ACP provides for Internet infrastructure.  The Locator/ID Separation Protocol (LISP) can be incrementally deployed, without a secure "flag day", and zero-touch management solution for complete networks.  Nodes supporting such an infrastructure (BRSKI offers Traffic Engineering, multihoming, and ACP) mobility benefits to early adopters, even when there are called ANI nodes (Autonomic Networking Infrastructure), see <xref target="I-D.ietf-anima-reference-model" format="default"/>.  Nodes that do not support an IDevID certificate but only an (insecure) vendor specific Unique Device Identifier (UDI) or nodes whose manufacturer does not support a MASA could use some future security reduced version relatively few LISP-capable sites.</t>
              <t indent="0">Design and development of BRSKI.</t>
        <t>When BRSKI is used to provision a domain certificate (which is called enrollment), LISP was largely motivated by the BRSKI registrar (acting as an enhanced EST server) must include problem statement produced by the otherName / AcpNodeName encoded ACP address October 2006 IAB Routing and domain name to the enrolling node (called pledge) via its response to the pledges EST CSR Attribute request that is mandatory in BRSKI.</t>
        <t>The Certification Authority in Addressing Workshop.  This document defines an ACP network must not change the otherName / AcpNodeName in Experimental Protocol for the certificate.  The ACP nodes can therefore find their ACP address and domain using this field in Internet community.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6830"/>
          <seriesInfo name="DOI" value="10.17487/RFC6830"/>
        </reference>
        <reference anchor="RFC7011" target="https://www.rfc-editor.org/info/rfc7011" quoteTitle="true" derivedAnchor="RFC7011">
          <front>
            <title>Specification of the domain certificate, both IP Flow Information Export (IPFIX) Protocol for themselves, as well the Exchange of Flow Information</title>
            <author initials="B." surname="Claise" fullname="B. Claise" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="B." surname="Trammell" fullname="B. Trammell" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="P." surname="Aitken" fullname="P. Aitken">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2013" month="September"/>
            <abstract>
              <t indent="0">This document specifies the IP Flow Information Export (IPFIX) protocol, which serves as a means for other nodes.</t>
        <t>The use of BRSKI in conjunction with transmitting Traffic Flow information over the ACP can also help network.  In order to further simplify maintenance and renewal of domain certificates.  Instead transmit Traffic Flow information from an Exporting Process to a Collecting Process, a common representation of relying on CRL, the lifetime flow data and a standard means of certificates can be made extremely small, for example in communicating them are required.  This document describes how the order of hours.  When IPFIX Data and Template Records are carried over a node fails to connect to the ACP within its certificate lifetime, it cannot connect to the ACP number of transport protocols from an IPFIX Exporting Process to renew its certificate across it (using just EST), but it can still renew its certificate as an "enrolled/expired pledge" via the BRSKI bootstrap proxy. IPFIX Collecting Process.  This requires document obsoletes RFC 5101.</t>
            </abstract>
          </front>
          <seriesInfo name="STD" value="77"/>
          <seriesInfo name="RFC" value="7011"/>
          <seriesInfo name="DOI" value="10.17487/RFC7011"/>
        </reference>
        <reference anchor="RFC7404" target="https://www.rfc-editor.org/info/rfc7404" quoteTitle="true" derivedAnchor="RFC7404">
          <front>
            <title>Using Only Link-Local Addressing inside an IPv6 Network</title>
            <author initials="M." surname="Behringer" fullname="M. Behringer">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="E." surname="Vyncke" fullname="E. Vyncke">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2014" month="November"/>
            <abstract>
              <t indent="0">In an IPv6 network, it is possible to use only that link-local addresses on infrastructure links between routers.  This document discusses the BRSKI registrar honors expired domain certificates advantages and that the pledge attempts disadvantages of this approach to perform TLS authentication facilitate the decision process for BRSKI bootstrap using its expired domain certificate before falling back to attempting a given network.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="7404"/>
          <seriesInfo name="DOI" value="10.17487/RFC7404"/>
        </reference>
        <reference anchor="RFC7426" target="https://www.rfc-editor.org/info/rfc7426" quoteTitle="true" derivedAnchor="RFC7426">
          <front>
            <title>Software-Defined Networking (SDN): Layers and Architecture Terminology</title>
            <author initials="E." surname="Haleplidis" fullname="E. Haleplidis" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="K." surname="Pentikousis" fullname="K. Pentikousis" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="S." surname="Denazis" fullname="S. Denazis">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="J." surname="Hadi Salim" fullname="J. Hadi Salim">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="D." surname="Meyer" fullname="D. Meyer">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="O." surname="Koufopavlou" fullname="O. Koufopavlou">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2015" month="January"/>
            <abstract>
              <t indent="0">Software-Defined Networking (SDN) refers to use its IDevID certificate for BRSKI.  This mechanism could also render CRLs unnecessary because the BRSKI registrar in conjunction with the CA would not renew revoked certificates - only a "Do-not-renew" list would be necessary on BRSKI registrars/CA.</t>
        <t>In new approach for network programmability, that is, the absence of BRSKI or less secure variants thereof, provisioning of certificates may involve one or more touches or non-standardized automation.  Node vendors usually support provisioning of certificates into nodes via PKCS#7 (see <xref target="RFC2315" format="default"/>) capacity to initialize, control, change, and may support this provisioning through vendor specific models manage network behavior dynamically via NETCONF (<xref target="RFC6241" format="default"/>).  If such nodes also support NETCONF Zero-Touch (<xref target="RFC8572" format="default"/>) then this can be combined to zero-touch provisioning open interfaces.  SDN emphasizes the role of domain certificates into nodes.  Unless there are equivalent integration software in running networks through the introduction of NETCONF connections across an abstraction for the ACP data forwarding plane and, by doing so, separates it from the control plane.  This separation allows faster innovation cycles at both planes as there is in BRSKI, this combination would not support zero-touch bootstrap across a not configured network though.</t>
      </section>
      <section anchor="discovery" numbered="true" toc="default">
        <name>ACP Neighbor discovery protocol selection</name>
        <t>This section discusses why GRASP DULL was chosen experience has already shown.  However, there is increasing confusion as to what exactly SDN is, what the discovery protocol
for L2 adjacent candidate ACP neighbors.  The contenders considered where GRASP, mDNS or LLDP.</t>
        <section anchor="discovery-lldp" numbered="true" toc="default">
          <name>LLDP</name>
          <t>LLDP layer structure is in an SDN architecture, and Cisco's earlier Cisco Discovery Protocol (CDP) are example of L2 discovery protocols that terminate
their messages on L2 ports.  If those protocols would be chosen for ACP neighbor discovery,
ACP neighbor discovery would therefore also terminate on L2 ports. how layers interface with each other.  This would prevent ACP construction
over non-ACP capable but LLDP or CDP enabled L2 switches.  LLDP has extensions using different MAC document, a product of the IRTF Software-Defined Networking Research Group (SDNRG), addresses these questions and this could have been an option provides a concise reference for ACP discovery as well, but the additional required
IEEE standardization SDN research community based on relevant peer-reviewed literature, the RFC series, and definition relevant documents by other standards organizations.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="7426"/>
          <seriesInfo name="DOI" value="10.17487/RFC7426"/>
        </reference>
        <reference anchor="RFC7435" target="https://www.rfc-editor.org/info/rfc7435" quoteTitle="true" derivedAnchor="RFC7435">
          <front>
            <title>Opportunistic Security: Some Protection Most of a profile for such a modified instance the Time</title>
            <author initials="V." surname="Dukhovni" fullname="V. Dukhovni">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2014" month="December"/>
            <abstract>
              <t indent="0">This document defines the concept "Opportunistic Security" in the context of LLDP seemed communications protocols.  Protocol designs based on Opportunistic Security use encryption even when authentication is not available, and use authentication when possible, thereby removing barriers to be
more work than the benefit widespread use of "reusing encryption on the existing protocol" LLDP for this very simple purpose.</t>
        </section>
        <!-- discovery-lldp -->
        <section anchor="discovery-mdns" numbered="true" toc="default">
          <name>mDNS Internet.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="7435"/>
          <seriesInfo name="DOI" value="10.17487/RFC7435"/>
        </reference>
        <reference anchor="RFC7575" target="https://www.rfc-editor.org/info/rfc7575" quoteTitle="true" derivedAnchor="RFC7575">
          <front>
            <title>Autonomic Networking: Definitions and L2 support</name>
          <t>Multicast DNNS (mDNS) <xref target="RFC6762" format="default"/> with DNS Service Discovery (DNS-SD) Resource Records (RRs) as defined Design Goals</title>
            <author initials="M." surname="Behringer" fullname="M. Behringer">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="M." surname="Pritikin" fullname="M. Pritikin">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="S." surname="Bjarnason" fullname="S. Bjarnason">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="A." surname="Clemm" fullname="A. Clemm">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="B." surname="Carpenter" fullname="B. Carpenter">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="S." surname="Jiang" fullname="S. Jiang">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="L." surname="Ciavaglia" fullname="L. Ciavaglia">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2015" month="June"/>
            <abstract>
              <t indent="0">Autonomic systems were first described in <xref target="RFC6763" format="default"/> 2001.  The fundamental goal is a key contender as an ACP discovery protocol. because it relies on link-local IP multicast,
it does operates at the subnet level, self-management, including self-configuration, self-optimization, self-healing, and self-protection.  This is also found in L2 switches.  The authors
of this achieved by an autonomic function having minimal dependencies on human administrators or centralized management systems.  It usually implies distribution across network elements.</t>
              <t indent="0">This document defines common language and outlines design goals (and what are not aware of mDNS implementation that terminate their mDNS messages
on L2 ports instead of the subnet level.  If mDNS was used as the ACP discovery mechanism on
an ACP capable (L3)/L2 switch as outlined design goals) for autonomic functions.  A high-level reference model illustrates how functional elements in <xref target="acp-l2-switches" format="default"/>, then this would
be necessary to implement.  It an Autonomic Network interact.  This document is likely that termination of mDNS messages could only be applied to
all mDNS messages from such a port, which would then make it necessary to software forward any non-ACP
 related mDNS messages to maintain prior non-ACP mDNS functionality.  Adding support a product of the IRTF's Network Management Research Group.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="7575"/>
          <seriesInfo name="DOI" value="10.17487/RFC7575"/>
        </reference>
        <reference anchor="RFC7576" target="https://www.rfc-editor.org/info/rfc7576" quoteTitle="true" derivedAnchor="RFC7576">
          <front>
            <title>General Gap Analysis for ACP into such
 L2 switches with mDNS could therefore create regression problems Autonomic Networking</title>
            <author initials="S." surname="Jiang" fullname="S. Jiang">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="B." surname="Carpenter" fullname="B. Carpenter">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="M." surname="Behringer" fullname="M. Behringer">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2015" month="June"/>
            <abstract>
              <t indent="0">This document provides a problem statement and general gap analysis for prior mDNS functionality an IP-based Autonomic Network that is mainly based on those nodes.
With low performance distributed network devices.  The document provides background by reviewing the current status of software forwarding in many L2 switches, this could also make autonomic aspects of IP networks and the ACP
risky extent to support which current network management depends on such L2 switches.</t>
        </section>
        <!-- discovery-mdns -->
        <section anchor="discovery-comparison" numbered="true" toc="default">
          <name>Why DULL GRASP</name>
          <t>LLDP was not considered because of centralization and human administrators.  Finally, the above mentioned issues. mDNS was not selected
because of document outlines the above L2 mDNS considerations general features that are missing from current network abilities and because are needed in the ideal Autonomic Network concept.</t>
              <t indent="0">This document is a product of the following additional points:</t>
          <t>If mDNS was not already existing in IRTF's Network Management Research Group.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="7576"/>
          <seriesInfo name="DOI" value="10.17487/RFC7576"/>
        </reference>
        <reference anchor="RFC7585" target="https://www.rfc-editor.org/info/rfc7585" quoteTitle="true" derivedAnchor="RFC7585">
          <front>
            <title>Dynamic Peer Discovery for RADIUS/TLS and RADIUS/DTLS Based on the Network Access Identifier (NAI)</title>
            <author initials="S." surname="Winter" fullname="S. Winter">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="M." surname="McCauley" fullname="M. McCauley">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2015" month="October"/>
            <abstract>
              <t indent="0">This document specifies a node, it would be more work means to implement than
DULL GRASP, and if an existing implementation of mDNS was used, it would likely be more code
space than find authoritative RADIUS servers for a separate implementation of DULL GRASP given realm.  It is used in conjunction with either RADIUS over Transport Layer Security (RADIUS/TLS) or a shared implementation of DULL
GRASP RADIUS over Datagram Transport Layer Security (RADIUS/DTLS).</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="7585"/>
          <seriesInfo name="DOI" value="10.17487/RFC7585"/>
        </reference>
        <reference anchor="RFC7721" target="https://www.rfc-editor.org/info/rfc7721" quoteTitle="true" derivedAnchor="RFC7721">
          <front>
            <title>Security and Privacy Considerations for IPv6 Address Generation Mechanisms</title>
            <author initials="A." surname="Cooper" fullname="A. Cooper">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="F." surname="Gont" fullname="F. Gont">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="D." surname="Thaler" fullname="D. Thaler">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2016" month="March"/>
            <abstract>
              <t indent="0">This document discusses privacy and security considerations for several IPv6 address generation mechanisms, both standardized and non-standardized.  It evaluates how different mechanisms mitigate different threats and GRASP in the ACP.</t>
        </section>
        <!-- discovery-comparison -->
      </section>
      <!-- discovery-->
      <section anchor="why-rpl" numbered="true" toc="default">
        <name>Choice of routing protocol (RPL)</name>
        <t>This section motivates why RPL trade-offs that implementors, developers, and users face in choosing different addresses or address generation mechanisms.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="7721"/>
          <seriesInfo name="DOI" value="10.17487/RFC7721"/>
        </reference>
        <reference anchor="RFC7761" target="https://www.rfc-editor.org/info/rfc7761" quoteTitle="true" derivedAnchor="RFC7761">
          <front>
            <title>Protocol Independent Multicast - "IPv6 Routing Sparse Mode (PIM-SM): Protocol for Low-Power Specification (Revised)</title>
            <author initials="B." surname="Fenner" fullname="B. Fenner">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="M." surname="Handley" fullname="M. Handley">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="H." surname="Holbrook" fullname="H. Holbrook">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="I." surname="Kouvelas" fullname="I. Kouvelas">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="R." surname="Parekh" fullname="R. Parekh">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="Z." surname="Zhang" fullname="Z. Zhang">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="L." surname="Zheng" fullname="L. Zheng">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2016" month="March"/>
            <abstract>
              <t indent="0">This document specifies Protocol Independent Multicast - Sparse Mode (PIM-SM).  PIM-SM is a multicast routing protocol that can use the underlying unicast routing information base or a separate multicast-capable routing information base.  It builds unidirectional shared trees rooted at a Rendezvous Point (RP) per group, and Lossy Networks (<xref target="RFC6550" format="default"/> was chosen as it optionally creates shortest-path trees per source.</t>
              <t indent="0">This document obsoletes RFC 4601 by replacing it, addresses the default (and in this specification only) routing protocol for errata filed against it, removes the ACP.  The choice optional (*,*,RP), PIM Multicast Border Router features and above explained profile was derived from a pre-standard implementation of ACP authentication using IPsec that was successfully deployed in operational networks.</t>
        <t>Requirements for routing in lack sufficient deployment experience (see Appendix A), and moves the ACP are:
                        </t>
        <ul spacing="compact">
          <li>Self-management: The ACP must build automatically, without human intervention.  Therefore, routing protocol must also work completely automatically.  RPL PIM specification to Internet Standard.</t>
            </abstract>
          </front>
          <seriesInfo name="STD" value="83"/>
          <seriesInfo name="RFC" value="7761"/>
          <seriesInfo name="DOI" value="10.17487/RFC7761"/>
        </reference>
        <reference anchor="RFC7950" target="https://www.rfc-editor.org/info/rfc7950" quoteTitle="true" derivedAnchor="RFC7950">
          <front>
            <title>The YANG 1.1 Data Modeling Language</title>
            <author initials="M." surname="Bjorklund" fullname="M. Bjorklund" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2016" month="August"/>
            <abstract>
              <t indent="0">YANG is a simple, self-managing protocol, which does not require zones or areas; it is also self-configuring, since data modeling language used to model configuration is carried as part of data, state data, Remote Procedure Calls, and notifications for network management protocols.  This document describes the protocol (see Section 6.7.6 syntax and semantics of <xref target="RFC6550" format="default"/>).</li>
          <li>Scale: The ACP builds over an entire domain, which could be a large enterprise or service provider network.  The routing protocol must therefore support domains version 1.1 of 100,000 nodes or more, ideally without the need for zoning or separation into areas.  RPL has this scale property.  This YANG language.  YANG version 1.1 is based on extensive use a maintenance release of default routing.</li>
          <li>Low resource consumption: The ACP supports traditional network infrastructure, thus runs in addition to traditional protocols.  The ACP, and specifically the routing protocol must have low resource consumption both in terms of memory and CPU requirements.  Specifically, at edge nodes, where memory YANG language, addressing ambiguities and CPU defects in the original specification.  There are scarce, consumption should be minimal.  RPL builds a DODAG, where the main resource consumption is at the root small number of backward incompatibilities from YANG version 1.  This document also specifies the DODAG.  The closer YANG mappings to the edge of the network, Network Configuration Protocol (NETCONF).</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="7950"/>
          <seriesInfo name="DOI" value="10.17487/RFC7950"/>
        </reference>
        <reference anchor="RFC8028" target="https://www.rfc-editor.org/info/rfc8028" quoteTitle="true" derivedAnchor="RFC8028">
          <front>
            <title>First-Hop Router Selection by Hosts in a Multi-Prefix Network</title>
            <author initials="F." surname="Baker" fullname="F. Baker">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="B." surname="Carpenter" fullname="B. Carpenter">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2016" month="November"/>
            <abstract>
              <t indent="0">This document describes expected IPv6 host behavior in a scenario that has more than one prefix, each allocated by an upstream network that is assumed to implement BCP 38 ingress filtering, when the less state needs host has multiple routers to be maintained.  This adapts nicely choose from.  It also applies to other scenarios such as the typical network design.  Also, all changes below a common parent node are kept below usage of stateful firewalls that parent node.</li>
          <li>Support for unstructured address space: In the Autonomic Networking Infrastructure, node addresses are identifiers, and may not be assigned effectively act as address-based filters.  Host behavior in choosing a topological way.  Also, nodes first-hop router may move topologically, without changing their address.  Therefore, interact with source address selection in a given implementation.  However, the routing protocol must support completely unstructured selection of the source address space.  RPL is specifically made for mobile ad-hoc networks, with no assumptions on topologically aligned addressing.</li>
          <li>Modularity: To keep a packet is done before the initial implementation small, yet allow later first-hop router for more complex methods, it that packet is highly desirable chosen. Given that the routing protocol has a simple base functionality, but can import new functional modules if needed.  RPL has this property network or host is, or appears to be, multihomed with multiple provider-allocated addresses, that the concept of "objective function", which is a plugin host has elected to modify routing behavior.</li>
          <li>Extensibility: Since the Autonomic Networking Infrastructure is use a new concept, it is likely source address in a given prefix, and that changes some but not all neighboring routers are advertising that prefix in the way of operation will happen over time.  RPL allows for new objective functions their Router Advertisement Prefix Information Options, this document specifies to be introduced later, which allow changes to the way the routing protocol creates the DAGs.</li>
          <li>Multi-topology support: router a host should present its transmission.  It may become necessary in the future to support more than one DODAG for different purposes, using different objective functions.  RPL allow updates RFC 4861.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8028"/>
          <seriesInfo name="DOI" value="10.17487/RFC8028"/>
        </reference>
        <reference anchor="RFC8126" target="https://www.rfc-editor.org/info/rfc8126" quoteTitle="true" derivedAnchor="RFC8126">
          <front>
            <title>Guidelines for the creation Writing an IANA Considerations Section in RFCs</title>
            <author initials="M." surname="Cotton" fullname="M. Cotton">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="B." surname="Leiba" fullname="B. Leiba">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="T." surname="Narten" fullname="T. Narten">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2017" month="June"/>
            <abstract>
              <t indent="0">Many protocols make use of several parallel DODAGs, should this be required.  This could be used to create different topologies points of extensibility that use constants to reach different roots.</li>
          <li>No need for path optimization: RPL does not necessarily compute the optimal path between any two nodes.  However, the ACP does not require this today, since it carries mainly non-delay-sensitive feedback loops.  It is possible identify various protocol parameters.  To ensure that different optimization schemes become necessary in the future, but RPL can be expanded (see point "Extensibility" above).</li>
        </ul>
      </section>
      <section anchor="acp-grasp" numbered="true" toc="default">
        <name>ACP Information Distribution and multicast</name>
        <t>IP multicast is not used by the ACP because the ANI (Autonomic Networking Infrastructure) itself does values in these fields do not require IP multicast
        but only service announcement/discovery.  Using IP multicast for that would have made it
        necessary conflicting uses and to develop promote interoperability, their allocations are often coordinated by a zero-touch auto configuring solution for ASM (Any Source Multicast - central record keeper.  For IETF protocols, that role is filled by the original form of IP multicast defined Internet Assigned Numbers Authority (IANA).</t>
              <t indent="0">To make assignments in <xref target="RFC1112" format="default"/>), a given registry prudently, guidance describing the conditions under which
        would new values should be quite complex assigned, as well as when and difficult how modifications to justify.  One aspect of complexity
        where no attempt at a solution has been described
        in IETF documents is the automatic-selection of
        routers that should existing values can be PIM Sparse Mode (PIM-SM) Rendezvous Points (RPs) (see <xref target="RFC7761" format="default"/>).  The other aspects of complexity
        are made, is needed.  This document defines a framework for the implementation documentation of MLD (<xref target="RFC4604" format="default"/>), PIM-SM and Anycast-RP (see <xref target="RFC4610" format="default"/>).  If those implementations already
        exist in a product, then they would be very likely tied these guidelines by specification authors, in order to accelerated forwarding
        which consumes hardware resources, assure that the provided guidance for the IANA Considerations is clear and addresses the various issues that are likely in return is difficult to justify as a cost the operation of performing only service discovery.</t>
        <t>Some future ASA may need high performance in-network data replication.  That a registry.</t>
              <t indent="0">This is the case
        when the use third edition of IP multicast is justified.  Such this document; it obsoletes RFC 5226.</t>
            </abstract>
          </front>
          <seriesInfo name="BCP" value="26"/>
          <seriesInfo name="RFC" value="8126"/>
          <seriesInfo name="DOI" value="10.17487/RFC8126"/>
        </reference>
        <reference anchor="RFC8316" target="https://www.rfc-editor.org/info/rfc8316" quoteTitle="true" derivedAnchor="RFC8316">
          <front>
            <title>Autonomic Networking Use Case for Distributed Detection of Service Level Agreement (SLA) Violations</title>
            <author initials="J." surname="Nobre" fullname="J. Nobre">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="L." surname="Granville" fullname="L. Granville">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="A." surname="Clemm" fullname="A. Clemm">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="A." surname="Gonzalez Prieto" fullname="A. Gonzalez Prieto">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2018" month="February"/>
            <abstract>
              <t indent="0">This document describes an ASA can then experimental use service discovery
        from ACP GRASP, and then they do not need ASM but only SSM (Source Specific Multicast, see <xref target="RFC4607" format="default"/>) case that employs autonomic networking for the IP multicast replication.  SSM itself can simply be enabled monitoring of Service Level Agreements (SLAs).  The use case is for detecting violations of SLAs in a distributed fashion.  It strives to optimize and dynamically adapt the Data-Plane
        (or even autonomic deployment of active measurement probes in an update to a way that maximizes the ACP) likelihood of detecting service-level violations with a given resource budget to perform active measurements.  This optimization and adaptation should be done without any other configuration than just enabling it
        on all nodes and only requires outside guidance or intervention.</t>
              <t indent="0">This document is a simpler version product of MLD (see <xref target="RFC5790" format="default"/>).</t>
        <t>LSP (Link State Protocol) based IGP routing protocols typically have the IRTF Network Management Research Group (NMRG).  It is published for informational purposes.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8316"/>
          <seriesInfo name="DOI" value="10.17487/RFC8316"/>
        </reference>
        <reference anchor="RFC8366" target="https://www.rfc-editor.org/info/rfc8366" quoteTitle="true" derivedAnchor="RFC8366">
          <front>
            <title>A Voucher Artifact for Bootstrapping Protocols</title>
            <author initials="K." surname="Watsen" fullname="K. Watsen">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="M." surname="Richardson" fullname="M. Richardson">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="M." surname="Pritikin" fullname="M. Pritikin">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="T." surname="Eckert" fullname="T. Eckert">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2018" month="May"/>
            <abstract>
              <t indent="0">This document defines a mechanism strategy to
        flood information, and such securely assign a mechanism could be used pledge to flood GRASP objectives an owner using an artifact signed, directly or indirectly, by
        defining them to be information of that IGP. the pledge's manufacturer.  This would be artifact is known as a possible optimization
        in future variations of the ACP that do use "voucher".</t>
              <t indent="0">This document defines an LSP routing protocol.  Note though artifact format as a YANG-defined JSON document that
        such has been signed using a mechanism would not work easily for GRASP M_DISCOVERY messages which Cryptographic Message Syntax (CMS) structure.  Other YANG-derived formats are intelligently
        (constrained) flooded not across possible.  The voucher artifact is normally generated by the whole ACP, but pledge's manufacturer (i.e., the Manufacturer Authorized Signing Authority (MASA)).</t>
              <t indent="0">This document only up defines the voucher artifact, leaving it to a node where a responder is found.
        We do expect that many future services in ASA will have only few consuming ASA, other documents to describe specialized protocols for accessing it.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8366"/>
          <seriesInfo name="DOI" value="10.17487/RFC8366"/>
        </reference>
        <reference anchor="RFC8368" target="https://www.rfc-editor.org/info/rfc8368" quoteTitle="true" derivedAnchor="RFC8368">
          <front>
            <title>Using an Autonomic Control Plane for Stable Connectivity of Network Operations, Administration, and Maintenance (OAM)</title>
            <author initials="T." surname="Eckert" fullname="T. Eckert" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="M." surname="Behringer" fullname="M. Behringer">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2018" month="May"/>
            <abstract>
              <t indent="0">Operations, Administration, and Maintenance (OAM), as per BCP 161, for those cases,
        M_DISCOVERY is the more efficient method than flooding across the whole domain.</t>
        <t>Because the ACP uses RPL, one desirable future extension data networks is often subject to use RPLs existing
        notion the problem of DODAG, which are loop-free distribution trees, circular dependencies when relying on connectivity provided by the network to make GRASP flooding more efficient
        both be managed for M_FLOOD the OAM purposes.</t>
              <t indent="0">Provisioning while bringing up devices and M_DISCOVERY. See <xref target="ACP_interfaces" format="default"/> how this will networks tends to be
        specifically beneficial when using NBMA interfaces.  This
        is not currently specified more difficult to automate than service provisioning later on.  Changes in this document core network functions impacting reachability cannot be automated because it is not quite clear yet what
        exactly of ongoing connectivity requirements for the implications OAM equipment itself, and widely used OAM protocols are not secure enough to make GRASP flooding depend on RPL DODAG convergence
        and how difficult it would be to let GRASP flooding access the DODAG information.</t>
      </section>

      <section anchor="domain-usage" numbered="true" toc="default">
        <name>CAs, domains and routing subdomains</name>
        <t>There is a wide range of setting up different ACP solution by appropriately using CAs and the domain and rsub elements in the acp-node-name in the domain certificate.  We summarize these options here as they have been explained in different parts of carried across the network without security concerns.</t>
              <t indent="0">This document describes how to integrate OAM processes with an autonomic control plane in before and discuss possible order to provide stable and desirable extensions:</t>
        <t>An ACP domain secure connectivity for those OAM processes.  This connectivity is the set of all ACP nodes that can authenticate each other as belonging not subject to the same ACP network using the ACP domain membership check (<xref target="certcheck" format="default"/>).  GRASP inside the ACP is run across all transitively connected ACP nodes aforementioned circular dependencies.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8368"/>
          <seriesInfo name="DOI" value="10.17487/RFC8368"/>
        </reference>
        <reference anchor="RFC8398" target="https://www.rfc-editor.org/info/rfc8398" quoteTitle="true" derivedAnchor="RFC8398">
          <front>
            <title>Internationalized Email Addresses in X.509 Certificates</title>
            <author initials="A." surname="Melnikov" fullname="A. Melnikov" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="W." surname="Chuang" fullname="W. Chuang" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2018" month="May"/>
            <abstract>
              <t indent="0">This document defines a domain.</t>
        <t>The rsub element new name form for inclusion in the acp-node-name permits the use otherName field of addresses from different ULA prefixes.  One use case is to create multiple physical networks that initially may be separated with one ACP domain but different routing subdomains, so that all nodes can mutual trust their ACP certificates (not depending on rsub) an X.509 Subject Alternative Name and so Issuer Alternative Name extension that they could connect later together into a contiguous ACP network.</t>
        <t>One instance of such a use case is an ACP for regions interconnected via allows a non-ACP enabled core, for example due certificate subject to be associated with an internationalized email address.</t>
              <t indent="0">This document updates RFC 5280.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8398"/>
          <seriesInfo name="DOI" value="10.17487/RFC8398"/>
        </reference>
        <reference anchor="RFC8402" target="https://www.rfc-editor.org/info/rfc8402" quoteTitle="true" derivedAnchor="RFC8402">
          <front>
            <title>Segment Routing Architecture</title>
            <author initials="C." surname="Filsfils" fullname="C. Filsfils" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="S." surname="Previdi" fullname="S. Previdi" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="L." surname="Ginsberg" fullname="L. Ginsberg">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="B." surname="Decraene" fullname="B. Decraene">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="S." surname="Litkowski" fullname="S. Litkowski">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="R." surname="Shakir" fullname="R. Shakir">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2018" month="July"/>
            <abstract>
              <t indent="0">Segment Routing (SR) leverages the absence source routing paradigm.  A node steers a packet through an ordered list of product support for ACP on the core nodes. ACP connect configurations as defined in this document instructions, called "segments".  A segment can be used to extend and interconnect those ACP islands represent any instruction, topological or service based.  A segment can have a semantic local to the NOC and merge them into an SR node or global within an SR domain.  SR provides a single ACP when later that product support gap is closed.</t>
        <t>Note mechanism that RPL scales very well.  It is not necessary allows a flow to use multiple routing subdomains be restricted to scale ACP domains in a way that would be required if other routing protocols where used.  They exist specific topological path, while maintaining per-flow state only as options for at the above mentioned reasons.</t>
        <t>If different ACP domains are to be created that should not allow to connect to each other by default, these ACP domains simply need ingress node(s) to have different domain elements in the acp-node-name.  These domain elements SR domain.</t>
              <t indent="0">SR can be arbitrary, including subdomains of one another: Domains "example.com" and "research.example.com" are separate domains if both are domain elements in directly applied to the acp-node-name of certificates.</t>
        <t>It is not necessary MPLS architecture with no change to have a separate CA for different ACP domains: the forwarding plane.  A segment is encoded as an operator can use MPLS label.  An ordered list of segments is encoded as a single CA to sign certificates for multiple ACP domains that are not allowed to connect stack of labels.  The segment to each other because process is on the checks for ACP adjacencies includes comparison top of the domain part.</t>
        <t>If multiple independent networks choose the same domain name but had their own CA, these would not form a single ACP domain because stack.  Upon completion of CA mismatch.  Therefore, there is no problem in choosing domain names that are potentially also used by others.  Nevertheless it a segment, the related label is highly recommended to use domain names that one popped from the stack.</t>
              <t indent="0">SR can have high probability to be unique.  It is recommended applied to use domain names that start the IPv6 architecture, with a DNS domain names owned by the assigning organization and unique within it.  For example, "acp.example.com" if you own "example.com".</t>
      </section>
      <section anchor="intent" numbered="true" toc="default">
        <name>Intent for the ACP</name>
        <t>Intent new type of routing header.  A segment is the architecture component encoded as an IPv6 address.  An ordered list of autonomic networks according to
 <xref target="I-D.ietf-anima-reference-model" format="default"/> that allows operators to issue policies to
the network.  Its applicability for use segments is quite  flexible and freeform, with potential applications including
policies flooded across ACP GRASP and interpreted on every ACP node.</t>
        <t>One concern for future definitions encoded as an ordered list of Intent solutions IPv6 addresses in the routing header.  The active segment is indicated by the problem Destination Address (DA) of circular dependencies
when expressing Intent policies about the ACP itself.</t>
        <t>For example, Intent could indicate packet.  The next active segment is indicated by a pointer in the desire new routing header.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8402"/>
          <seriesInfo name="DOI" value="10.17487/RFC8402"/>
        </reference>
        <reference anchor="RFC8572" target="https://www.rfc-editor.org/info/rfc8572" quoteTitle="true" derivedAnchor="RFC8572">
          <front>
            <title>Secure Zero Touch Provisioning (SZTP)</title>
            <author initials="K." surname="Watsen" fullname="K. Watsen">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="I." surname="Farrer" fullname="I. Farrer">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="M." surname="Abrahamsson" fullname="M. Abrahamsson">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2019" month="April"/>
            <abstract>
              <t indent="0">This document presents a technique to build an ACP across all domains
that have securely provision a common parent domain (without relying on the rsub/routing-subdomain
solution defined networking device when it is booting in a factory-default state.  Variations in this document).  For example, ACP nodes with domain "example.com",
 "access.example.com", "core.example.com" and "city.core.example.com"
should all establish one single ACP.</t>
        <t>If each domain has its own source of Intent, then the Intent would simply have solution enable it to
allow adding the peer domains TA be used on both public and domain names private networks.  The provisioning steps are able to update the parameters for the ACP domain membership check
(<xref target="certcheck" format="default"/>) so that nodes from those other domains are accepted as ACP peers.</t>
        <t>If this Intent was boot image, commit an initial configuration, and execute arbitrary scripts to be originated only from one domain, it could likely not be made address auxiliary needs.  The updated device is subsequently able to work because the establish secure connections with other domains will not build any ACP connection amongst each other,
whether they use the same or different CA due systems.  For instance, a device may establish NETCONF (RFC 6241) and/or RESTCONF (RFC 8040) connections with deployment-specific network management systems.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8572"/>
          <seriesInfo name="DOI" value="10.17487/RFC8572"/>
        </reference>
        <reference anchor="RFC8684" target="https://www.rfc-editor.org/info/rfc8684" quoteTitle="true" derivedAnchor="RFC8684">
          <front>
            <title>TCP Extensions for Multipath Operation with Multiple Addresses</title>
            <author initials="A." surname="Ford" fullname="A. Ford">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="C." surname="Raiciu" fullname="C. Raiciu">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="M." surname="Handley" fullname="M. Handley">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="O." surname="Bonaventure" fullname="O. Bonaventure">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="C." surname="Paasch" fullname="C. Paasch">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2020" month="March"/>
            <abstract>
              <t indent="0">TCP/IP communication is currently restricted to the ACP domain membership check.</t>
        <t>If the  domains a single path per connection, yet multiple paths often exist between peers. The simultaneous use of these multiple paths for a TCP/IP session would improve resource usage within the same CA one could change the ACP setup network and thus improve user experience through higher throughput and improved resilience to permit for network failure.</t>
              <t indent="0">Multipath TCP provides the
ACP ability to be established simultaneously use multiple paths between two ACP nodes with different acp-domain-names, but only
 for peers. This document presents a set of extensions to traditional TCP to support multipath operation. The protocol offers the purpose same type of disseminating limited information,
such as Intent, but not service to set up full ACP connectivity, specifically not RPL routing applications as TCP (i.e., a reliable bytestream), and passing of arbitrary GRASP information.  Unless it provides the Intent policies permit this components necessary to happen establish and use multiple TCP flows across domain boundaries.</t>
        <t>This type potentially disjoint paths.</t>
              <t indent="0">This document specifies v1 of approach where the ACP first allows Intent to operate Multipath TCP, obsoleting v0 as specified in RFC 6824, through clarifications and only then
sets up modifications primarily driven by deployment experience.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8684"/>
          <seriesInfo name="DOI" value="10.17487/RFC8684"/>
        </reference>
        <reference anchor="RFC8739" target="https://www.rfc-editor.org/info/rfc8739" quoteTitle="true" derivedAnchor="RFC8739">
          <front>
            <title>Support for Short-Term, Automatically Renewed (STAR) Certificates in the rest of ACP connectivity  based on Intent policy could also be used Automated Certificate Management Environment (ACME)</title>
            <author initials="Y." surname="Sheffer" fullname="Y. Sheffer">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="D." surname="Lopez" fullname="D. Lopez">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="O." surname="Gonzalez de Dios" fullname="O. Gonzalez de Dios">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="A." surname="Pastor Perales" fullname="A. Pastor Perales">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="T." surname="Fossati" fullname="T. Fossati">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2020" month="March"/>
            <abstract>
              <t indent="0">Public key certificates need to
enable Intent policies be revoked when they are compromised, that would limit functionality across the ACP inside a domain,
as long as no policy would disturb is, when the distribution of Intent. For example, associated private key is exposed to limit
reachability across an unauthorized entity.  However, the ACP revocation process is often unreliable. An alternative to certain type revocation is issuing a sequence of nodes or locations certificates, each with a short validity period, and terminating the sequence upon compromise.  This memo proposes an Automated Certificate Management Environment (ACME) extension to enable the issuance of nodes.</t>
      </section>
      <section anchor="reuse-acp" numbered="true" toc="default">
        <name>Adopting ACP concepts Short-Term, Automatically Renewed (STAR) X.509 certificates.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8739"/>
          <seriesInfo name="DOI" value="10.17487/RFC8739"/>
        </reference>
        <reference anchor="RFC8981" target="https://www.rfc-editor.org/info/rfc8981" quoteTitle="true" derivedAnchor="RFC8981">
          <front>
            <title>Temporary Address Extensions for other environments</name>
        <t>The ACP as specified Stateless Address Autoconfiguration in this IPv6</title>
            <author initials="F." surname="Gont" fullname="F. Gont">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="S." surname="Krishnan" fullname="S. Krishnan">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="T." surname="Narten" fullname="T. Narten">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="R." surname="Draves" fullname="R. Draves">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2021" month="February"/>
            <abstract>
              <t indent="0">This document is very explicit about the choice of options describes an extension to
allow interoperable implementations.  The choices made may not be the best for all environments,
but the concepts used by the ACP can be used IPv6 Stateless Address Autoconfiguration that causes hosts to build derived solutions:</t>
        <t>The ACP specifies generate temporary addresses with randomized interface identifiers for each prefix advertised with autoconfiguration enabled. Changing addresses over time limits the use window of ULA time during which eavesdroppers and deriving its prefix from other information collectors may trivially perform address-based network-activity correlation when the domain name
so that no same address allocation is required to deploy the ACP. The ACP will equally
work not using ULA but any other /48 IPv6 prefix.  This prefix could simply be a configuration
of employed for multiple transactions by the ACP registrars (for example when using BRSKI) to enroll same host. Additionally, it reduces the domain certificates - instead window of the ACP registrar deriving the /48 ULA prefix from the AN domain name.</t>

        <t>Some solutions may already have an auto-addressing scheme, for example derived from
existing unique device identifiers (e.g., MAC addresses).  In those cases it may not be desirable
to assign addresses to devices exposure of a host as being accessible via the ACP an address information field that becomes revealed as a result of active communication. This document obsoletes RFC 4941.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8981"/>
          <seriesInfo name="DOI" value="10.17487/RFC8981"/>
        </reference>
        <reference anchor="RFC8992" target="https://www.rfc-editor.org/info/rfc8992" quoteTitle="true" derivedAnchor="RFC8992">
          <front>
            <title>Autonomic IPv6 Edge Prefix Management in Large-Scale Networks</title>
            <author initials="S" surname="Jiang" fullname="Sheng Jiang" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="Z" surname="Du" fullname="Zongpeng Du">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="B" surname="Carpenter" fullname="Brian Carpenter">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="Q" surname="Sun" fullname="Qiong Sun">
              <organization showOnFrontPage="true"/>
            </author>
            <date month="May" year="2021"/>
          </front>
          <seriesInfo name="RFC" value="8992"/>
          <seriesInfo name="DOI" value="10.17487/RFC8992"/>
        </reference>
        <reference anchor="RFC8993" target="https://www.rfc-editor.org/info/rfc8993" quoteTitle="true" derivedAnchor="RFC8993">
          <front>
            <title>A Reference Model for Autonomic Networking</title>
            <author initials="M" surname="Behringer" fullname="Michael H. Behringer" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="B" surname="Carpenter" fullname="Brian Carpenter">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="T" surname="Eckert" fullname="Toerless Eckert">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="L" surname="Ciavaglia" fullname="Laurent Ciavaglia">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="J" surname="Nobre" fullname="Jéferson Campos Nobre">
              <organization showOnFrontPage="true"/>
            </author>
            <date month="May" year="2021"/>
          </front>
          <seriesInfo name="RFC" value="8993"/>
          <seriesInfo name="DOI" value="10.17487/RFC8993"/>
        </reference>
        <reference anchor="I-D.ietf-roll-applicability-template" quoteTitle="true" target="https://tools.ietf.org/html/draft-ietf-roll-applicability-template-09" derivedAnchor="ROLL-APPLICABILITY">
          <front>
            <title>ROLL Applicability Statement Template</title>
            <author initials="M" surname="Richardson" fullname="Michael Richardson">
              <organization showOnFrontPage="true"/>
            </author>
            <date month="May" day="3" year="2016"/>
          </front>
          <seriesInfo name="Internet-Draft" value="draft-ietf-roll-applicability-template-09"/>
          <format type="TXT" target="https://www.ietf.org/archive/id/draft-ietf-roll-applicability-template-09.txt"/>
          <refcontent>Work in Progress</refcontent>
        </reference>
        <reference anchor="SR" target="https://en.wikipedia.org/w/index.php?title=Single-root_input/output_virtualization&amp;oldid=978867619" quoteTitle="true" derivedAnchor="SR">
          <front>
            <title>Single-root input/output virtualization</title>
            <author>
              <organization showOnFrontPage="true">Wikipedia</organization>
            </author>
            <date month="September" year="2020"/>
          </front>
        </reference>
        <reference anchor="I-D.ietf-tls-dtls13" quoteTitle="true" target="https://tools.ietf.org/html/draft-ietf-tls-dtls13-43" derivedAnchor="TLS-DTLS13">
          <front>
            <title>The Datagram Transport Layer Security (DTLS) Protocol Version 1.3</title>
            <author fullname="Eric Rescorla">
              <organization showOnFrontPage="true">RTFM, Inc.</organization>
            </author>
            <author fullname="Hannes Tschofenig">
              <organization showOnFrontPage="true">Arm Limited</organization>
            </author>
            <author fullname="Nagendra Modadugu">
              <organization showOnFrontPage="true">Google, Inc.</organization>
            </author>
            <date month="April" day="30" year="2021"/>
            <abstract>
              <t indent="0">   This document specifies Version 1.3 of the way described
in this document.  The certificate may simply serve Datagram Transport Layer
   Security (DTLS) protocol.  DTLS 1.3 allows client/server applications
   to identify the ACP domain,
and communicate over the address field could be omitted. The only fix required Internet in the remaining a way the ACP operate that is designed to define another element in the domain certificate for
the two peers to decide who is the Decider prevent
   eavesdropping, tampering, and who is the Follower during secure channel building.
Note though that future work may leverage the acp address to authenticate "ownership"
of the address by the device.  If the address used by a device message forgery.

   The DTLS 1.3 protocol is derived from some
pre-existing permanent local ID (such as MAC address), then it would be useful to
store that address in intentionally based on the certificate using Transport Layer
   Security (TLS) 1.3 protocol and provides equivalent security
   guarantees with the format exception of the access address information
field or in a similar way.</t>

        <t>The ACP is defined as a separate VRF because it intends to support well managed
networks with a wide variety order protection/non-replayability.
   Datagram semantics of configurations.  Therefore, reliable,
configuration-indestructible connectivity cannot be achieved from the Data-Plane itself.
In solutions where all transit connectivity impacting functions underlying transport are fully automated (including security),
indestructible and resilient, it would be possible to eliminate the need for the ACP to be a separate VRF.
Consider preserved by the most simple example system
   DTLS protocol.

   This document obsoletes RFC 6347.

              </t>
            </abstract>
          </front>
          <seriesInfo name="Internet-Draft" value="draft-ietf-tls-dtls13-43"/>
          <format type="TXT" target="https://www.ietf.org/archive/id/draft-ietf-tls-dtls13-43.txt"/>
          <refcontent>Work in which there is no separate Data-Plane, but the ACP is the Data-Plane.  Add
BRSKI, Progress</refcontent>
        </reference>
        <reference anchor="X.509" target="https://www.itu.int/rec/T-REC-X.509" quoteTitle="true" derivedAnchor="X.509">
          <front>
            <title>Information technology - Open Systems Interconnection - The Directory: Public-key and it becomes a fully autonomic network attribute certificate frameworks</title>
            <seriesInfo name="ITU-T Recommendation" value="X.509"/>
            <author>
              <organization showOnFrontPage="true">ITU-T</organization>
            </author>
            <date month="October" year="2016"/>
          </front>
        </reference>
        <reference anchor="X.520" target="https://www.itu.int/rec/T-REC-X.520" quoteTitle="true" derivedAnchor="X.520">
          <front>
            <title>Information technology - except that it does not support
automatic addressing for user equipment.  This gap can then be closed for example by adding a
solution derived from <xref target="I-D.ietf-anima-prefix-management" format="default"/>.</t>
        <t>TCP/TLS as the protocols to provide reliability Open Systems Interconnection - The Directory: Selected attribute types</title>
            <seriesInfo name="ITU-T Recommendation" value="X.520"/>
            <author>
              <organization showOnFrontPage="true">ITU-T</organization>
            </author>
            <date month="October" year="2016"/>
          </front>
        </reference>
      </references>
    </references>
    <section anchor="further" numbered="true" toc="include" removeInRFC="false" pn="section-appendix.a">
      <name slugifiedName="name-background-and-future-infor">Background and security to GRASP in the ACP
may not be the preferred choice in constrained networks. For example, CoAP/DTLS
(Constrained Application Protocol) may be preferred where they are already used,
allowing to reduce the additional code space footprint for the ACP on
those devices. Hop-by-hop reliability for ACP GRASP messages could be made
to support protocols like DTLS by adding Future (Informative)</name>
      <t indent="0" pn="section-appendix.a-1">The following sections provide background information about aspects of the same type normative parts of
negotiation as defined in this document for ACP secure channel protocol negotiation.
End-to-end GRASP connections can be or associated mechanisms such as BRSKI (such as why specific choices were made to select their transport protocol
in future extensions of the ACP meant to better support constrained devices by
indicating the supported transport protocols (e.g. TLS/DTLS) via GRASP parameters ACP), and they discuss possible future variations of the GRASP objective through which the transport endpoint is discovered.</t>
        <t>The routing protocol RPL used for ACP.</t>
      <section anchor="address-spaces" numbered="true" toc="include" removeInRFC="false" pn="section-a.1">
        <name slugifiedName="name-acp-address-space-schemes">ACP Address Space Schemes</name>
        <t indent="0" pn="section-a.1-1">This document defines the Zone, Vlong, and Manual Addressing Sub-Schemes primarily to support address prefix assignment
via distributed, potentially uncoordinated ACP registrars as defined
in <xref target="acp-registrars" format="default" sectionFormat="of" derivedContent="Section 6.11.7"/>. This
costs a 48/46-bit identifier so that these ACP registrars can assign
nonconflicting address prefixes. This design does explicitly not optimize leave enough
bits to simultaneously support a large number of nodes (Node-ID),
plus a large prefix of local addresses for shortest paths and fastest convergence.  Variations every node, plus a
large enough set of the ACP may want bits to use identify a
different routing protocol or introduce more advanced RPL profiles.</t>
        <t>Variations such as what routing protocol zone. As a result,
the Zone and Vlong 8/16 Addressing Sub-Schemes attempt to use, or whether support all features but via
separate prefixes.</t>
        <t indent="0" pn="section-a.1-2">In networks that expect always to instantiate an ACP
in rely on a VRF or (as suggested above) centralized PMS
as described <xref target="pms" format="default" sectionFormat="of" derivedContent="Section 9.2.5"/>, the actual Data-Plane, can 48/46-bits for
the Registrar-ID could be automatically chosen
in implementations built to support multiple options by deriving them from future parameters
in saved. Such variations of the certificate.  Parameters ACP
addressing mechanisms could be introduced through future work
in certificates should different ways. If a new otherName was introduced,
incompatible ACP variations could be limited to those that would
not need to created
where every design aspect of the ACP could be changed more often than certificates changed, including
all addressing choices. If instead a new addressing sub-scheme
would need to be updated anyhow;
Or by ensuring that these parameters can defined, it could be provisioned before the
variation of an ACP is activated in a node.  Using BRSKI, backward-compatible extension
of this could be done for example ACP specification. Information such as additional follow-up signaling directly after the certificate enrollment, still
leveraging the BRSKI TLS connection size of a
zone prefix and therefore not introducing any additional
connectivity requirements.</t>
        <t>Last but not least, secure channel protocols including their encapsulations are
easily added the length of the prefix assigned to the ACP solutions.  ACP hop-by-hop network layer secure channels
node itself could
also be replaced by end-to-end security plus other means for infrastructure
protection.  Any future network OAM should always use end-to-end security anyhow and can
leverage encoded via the domain certificates and extension field of the
acp-node-name.</t>
        <t indent="0" pn="section-a.1-3">Note that an explicitly defined Manual Addressing Sub-Scheme
is therefore not dependent on security always beneficial to
be provided provide an easy way for by ACP secure channels.</t> nodes to prohibit
incorrect non-autonomic configuration of any non-"Manual" ACP address spaces
and therefore ensure that such non-autonomic operations will never impact
correct routing for any non-"Manual" ACP addresses assigned via
ACP certificates.</t>
      </section>
      <section anchor="futures" numbered="true" toc="default">
        <name>Further (future) options</name>
        <section anchor="auto-aggregation" anchor="bootstrap" numbered="true" toc="default">
          <name>Auto-aggregation of routes</name>
          <t>Routing in the ACP according toc="include" removeInRFC="false" pn="section-a.2">
        <name slugifiedName="name-brski-bootstrap-ani">BRSKI Bootstrap (ANI)</name>
        <t indent="0" pn="section-a.2-1">BRSKI describes how nodes with an IDevID certificate can securely and zero-touch enroll with an LDevID certificate to this specification only support the ACP.  BRSKI also leverages the
standard RPL mechanism ACP to enable zero-touch bootstrap of route optimization, e.g. keeping new nodes across networks without any configuration requirements across the transit nodes (e.g., no DHCP, DNS forwarding, and/or server setup).  This includes otherwise unconfigured networks as described in <xref target="secure-bootstrap" format="default" sectionFormat="of" derivedContent="Section 3.2"/>.  Therefore, BRSKI in conjunction with ACP provides for a secure and zero-touch management solution for complete networks.  Nodes supporting such an infrastructure (BRSKI and ACP) are called ANI nodes (Autonomic Networking Infrastructure), see <xref target="RFC8993" format="default" sectionFormat="of" derivedContent="RFC8993"/>.  Nodes that do not support an IDevID certificate but only routes that
are an (insecure) vendor-specific Unique Device Identifier (UDI) or nodes whose manufacturer does not towards the RPL root. This support a MASA could use some future, reduced-security version of BRSKI.</t>
        <t indent="0" pn="section-a.2-2">When BRSKI is known to scale used to networks with 20,000 or more nodes.
There provision a domain certificate (which is no auto-aggregation of routes for /48 ULA prefixes (when using rsub
in called enrollment), the acp-node-name) and/or Zone-ID based prefixes.</t>
          <t>Automatic assignment of Zone-ID BRSKI registrar (acting as an enhanced EST server) must include the otherName / AcpNodeName encoded ACP address and auto-aggregation of routes could
be achieved for example by configuring zone-boundaries, announcing domain name to the enrolling node (called a pledge) via GRASP
into its response to the zones pledge's EST CSR Attributes Request that is mandatory in BRSKI.</t>
        <t indent="0" pn="section-a.2-3">The CA in an ACP network must not change the zone parameters (zone-ID and /48 ULA prefix) and auto-aggregating
routes on otherName / AcpNodeName in the zone-boundaries. Nodes would assign certificate.  The ACP nodes can therefore find their Zone-ID ACP addresses and potentially
even /48 prefix based on domain using this field in the GRASP announcements.</t>
        </section>
        <section anchor="dp-dependency" numbered="true" toc="default">
          <name>More options domain certificate, both for avoiding IPv6 Data-Plane dependencies</name>
          <t>As described themselves as well as for other nodes.</t>
        <t indent="0" pn="section-a.2-4">The use of BRSKI in <xref target="general_addressing" format="default"/>, conjunction with the ACP depends can also help to further simplify maintenance and renewal of domain certificates.  Instead of relying on CRL, the
Data-Plane to establish IPv6 link-local addressing lifetime of certificates can be made extremely small, for example, on interfaces. Using the order of hours.  When a separate
MAC address for node fails to connect to the ACP allows within its certificate lifetime, it cannot connect to fully isolate the ACP from to renew its certificate across it (using just EST), but it can still renew its certificate as an "enrolled/expired pledge" via the Data-Plane in
a way BRSKI bootstrap proxy.  This requires only that is compatible with this specification. It is also an ideal option
when using Single-root input/output virtualization (SR-IOV - see
<eref target="https://en.wikipedia.org/wiki/Single-root_input/output_virtualization"/>)
 in an implementation to isolate the ACP because
different SR-IOV interfaces use different MAC addresses.</t>
          <t>When additional MAC address(es) are not available, separation of BRSKI registrar honors expired domain certificates and that the
ACP could be done at different demux points. The same subnet interface could have
a separate IPv6 interface pledge attempts to perform TLS authentication for the ACP and Data-Plane and therefore separate
link-local addresses BRSKI bootstrap using its expired domain certificate before falling back to attempting to use its IDevID certificate for both, where BRSKI.  This mechanism could also render CRLs unnecessary because the ACP interface is non-configurable on BRSKI registrar in conjunction with the Data-Plane. This too CA would be compatible with this specification and not
impact interoperability.</t>
          <t>An option that would require additional specification is to use renew revoked certificates -- only a different
Ethertype from 0x86DD (IPv6) to encapsulate IPv6 packets for the ACP. This "Do-not-renew" list would be a similar approach as used for IP authentication packets in <xref target="IEEE-802.1X" format="default"/>
which use necessary on the Extensible Authentication BRSKI registrar/CA.</t>
        <t indent="0" pn="section-a.2-5">In the absence of BRSKI or less secure variants thereof, the provisioning of certificates may involve one or more touches or nonstandardized automation.  Node vendors usually support the provisioning of certificates into nodes via PKCS #7 (see "<xref target="RFC2315" format="title" sectionFormat="of" derivedContent="PKCS #7: Cryptographic Message Syntax Version 1.5"/>" <xref target="RFC2315" format="default" sectionFormat="of" derivedContent="RFC2315"/>) and may support this provisioning through vendor-specific models via NETCONF ("<xref target="RFC6241" format="title" sectionFormat="of" derivedContent="Network Configuration Protocol over Local Area Network (EAPoL)
ethertype (0x88A2).</t>
          <t>Note that in the case (NETCONF)"/>" <xref target="RFC6241" format="default" sectionFormat="of" derivedContent="RFC6241"/>).  If such nodes also support NETCONF Zero Touch <xref target="RFC8572" format="default" sectionFormat="of" derivedContent="RFC8572"/>, then this can be combined with zero-touch provisioning of ANI nodes, all the above considerations equally
apply to domain certificates into nodes.  Unless there is the encapsulation equivalent integration of BRSKI packets including GRASP used for BRSKI.</t> NETCONF connections across the ACP as there is in BRSKI, this combination would not support zero-touch bootstrap across an unconfigured network, though.</t>
      </section>
      <section anchor="acp-api" anchor="discovery" numbered="true" toc="default">
          <name>ACP APIs and operational models (YANG)</name>
          <t>Future work should define YANG (<xref target="RFC7950" format="default"/>) data model
and/or node internal APIs to monitor and manage toc="include" removeInRFC="false" pn="section-a.3">
        <name slugifiedName="name-acp-neighbor-discovery-prot">ACP Neighbor Discovery Protocol Selection</name>
        <t indent="0" pn="section-a.3-1">This section discusses why GRASP DULL was chosen as the ACP.</t>
          <t>Support discovery protocol
for the L2-adjacent candidate ACP Adjacency Table (<xref target="adj-table" format="default"/>) neighbors.  The contenders that were considered were GRASP, mDNS, and ACP GRASP need to
be included into such model/API.</t>
        </section> LLDP.</t>
        <section anchor="future-rpl" anchor="discovery-lldp" numbered="true" toc="default">
          <name>RPL enhancements</name>
          <figure anchor="dual-noc">
            <name>Dual NOC</name>
            <artwork name="" type="" align="left" alt=""><![CDATA[

   ..... USA ......              ..... Europe ......

        NOC1                           NOC2
         |                              |
         |            metric 100        |
       ACP1 --------------------------- ACP2  .
         |                              |     . WAN
         | metric 10          metric 20 |     . Core
         |                              |     .
       ACP3 --------------------------- ACP4  .
         |            metric 100        |
         |                              |     .
         |                              |     . Sites
       ACP10                           ACP11  .

        ]]></artwork>
          </figure>
          <t>The profile toc="include" removeInRFC="false" pn="section-a.3.1">
          <name slugifiedName="name-lldp">LLDP</name>
          <t indent="0" pn="section-a.3.1-1">LLDP and Cisco's earlier Cisco Discovery Protocol (CDP) are examples of L2 discovery protocols that terminate
their messages on L2 ports.  If those protocols had been chosen for RPL specified in ACP neighbor discovery,
ACP neighbor discovery would also have terminated on L2 ports.  This would have prevented ACP construction
over non-ACP-capable, but LLDP- or CDP-enabled L2 switches.  LLDP has extensions using different MAC
addresses, and this document builds only one spanning-tree path set to a root, typically a registrar in one NOC. In the presence of multiple NOCs, routing toward the non-root NOCs may be suboptimal. <xref target="dual-noc" format="default"/> shows could have been an extreme example. Assuming that node ACP1 becomes option for ACP discovery as well, but the RPL root, traffic between ACP11 additional required
IEEE standardization and NOC2 will pass through ACP4-ACP3-ACP1-ACP2 instead definition of ACP4-ACP2 because the RPL calculated DODAG/routes are shortest paths towards the RPL root.</t>
          <t>To overcome these limitations, extensions/modifications to the RPL a profile can provide optimality for multiple NOCs.  This requires utilizing Data-Plane artifact including IPinIP encap/decap on ACP routers and processing of IPv6 RPI headers.  Alternatively, (Src,Dst) routing table entries could be used.</t>
          <t>Flooding such a modified instance of ACP GRASP messages can LLDP seemed to be further constrained and therefore optimized by flooding only via links that are part
more work than the benefit of "reusing the RPL DODAG.</t> existing protocol" LLDP for this very simple purpose.</t>
        </section>
        <section anchor="role-assignments" anchor="discovery-mdns" numbered="true" toc="default">
          <name>Role assignments</name>
          <t>ACP connect is an explicit mechanism to "leak" ACP traffic explicitly (for example toc="include" removeInRFC="false" pn="section-a.3.2">
          <name slugifiedName="name-mdns-and-l2-support">mDNS and L2 Support</name>
          <t indent="0" pn="section-a.3.2-1">Multicast DNS (mDNS) "<xref target="RFC6762" format="title" sectionFormat="of" derivedContent="Multicast DNS"/>" <xref target="RFC6762" format="default" sectionFormat="of" derivedContent="RFC6762"/> with DNS Service Discovery (DNS-SD) Resource Records (RRs) as defined in "<xref target="RFC6763" format="title" sectionFormat="of" derivedContent="DNS-Based Service Discovery"/>" <xref target="RFC6763" format="default" sectionFormat="of" derivedContent="RFC6763"/>
was a NOC). It is therefore also a possible security gap when it is easy to enable key contender as an ACP
 connect discovery protocol. Because it relies on arbitrary compromised ACP nodes.</t>
          <t>One simple solution link-local IP multicast,
it operates at the subnet level and is to define also found in L2 switches.  The authors
of this document are not aware of an extension in mDNS implementation that terminates its mDNS messages
on L2 ports instead of on the ACP certificates ACP information
field indicating subnet level.  If mDNS was used as the permission for ACP connect to be configured discovery mechanism on
an ACP-capable (L3)/L2 switch as outlined in <xref target="acp-l2-switches" format="default" sectionFormat="of" derivedContent="Section 7"/>, then this would
be necessary to implement.  It is likely that ACP node. This termination of mDNS messages could similarly only be done applied to decide whether
all mDNS messages from such a node is permitted port, which would then make it necessary to be a registrar or not.</t>
          <t>Tying the permitted "roles" of an ACP node software forward any non-ACP-related
mDNS messages to the maintain prior non-ACP mDNS functionality.  Adding support for ACP certificate provides
fairly strong protection against misconfiguration, but is still subject to code
modifications.</t>
          <t>Another interesting role to assign to certificates is that such
 L2 switches with mDNS could therefore create regression problems for prior mDNS functionality on those nodes.
With low performance of a NOC node. This would allow software forwarding in many L2 switches, this could also make the ACP
risky to
limit certain type of connections support on such as OAM TLS connections to only NOC initiator
or responders.</t> L2 switches.</t>
        </section>
        <section anchor="l3-transit" anchor="discovery-comparison" numbered="true" toc="default">
          <name>Autonomic L3 transit</name>
          <t>In this specification, toc="include" removeInRFC="false" pn="section-a.3.3">
          <name slugifiedName="name-why-dull-grasp">Why DULL GRASP?</name>
          <t indent="0" pn="section-a.3.3-1">LLDP was not considered because of the ACP can only establish autonomic connectivity across above mentioned issues. mDNS was not selected
because of the above L2
hops mDNS considerations and only explicitly configured options to tunnel across L3. Future because of the following additional points.</t>
          <t indent="0" pn="section-a.3.3-2">If mDNS was not already existing in a node, it would be more work should
specify mechanisms to automatically tunnel ACP across L3 networks. A hub&amp;spoke
option implement than
DULL GRASP, and if an existing implementation of mDNS was used, it would allow to tunnel across the Internet to likely be more code
space than a cloud separate implementation of DULL GRASP or central instance a shared implementation of DULL
GRASP and GRASP in the ACP,
a peer-to-peer tunneling mechanism could tunnel ACP islands across an L3VPN infrastructure.</t> ACP.</t>
        </section>
      </section>
      <section anchor="future-diag" anchor="why-rpl" numbered="true" toc="default">
          <name>Diagnostics</name>
          <t><xref target="diagnostics" format="default"/> describes diagnostics options that can be done
without changing toc="include" removeInRFC="false" pn="section-a.4">
        <name slugifiedName="name-choice-of-routing-protocol-">Choice of Routing Protocol (RPL)</name>
        <t indent="0" pn="section-a.4-1">This section motivates why RPL ("IPv6 Routing Protocol for Low-Power and Lossy Networks <xref target="RFC6550" format="default" sectionFormat="of" derivedContent="RFC6550"/>) was chosen as the external, interoperability affecting characteristics default (and in this specification only) routing protocol for the ACP.  The choice and above explained profile were derived from a pre-standard implementation of ACP implementations.</t>
          <t>Even better diagnostics of that was successfully deployed in operational networks.</t>
        <t indent="0" pn="section-a.4-2">The requirements for routing in the ACP operations are the following:
        </t>
        <ul spacing="normal" bare="false" empty="false" indent="3" pn="section-a.4-3">
          <li pn="section-a.4-3.1">Self-management: the ACP must build automatically, without human
	  intervention.  Therefore, the routing protocol must also work completely
	  automatically.  RPL is possible with additional
signaling extensions, such as:</t>
          <ol type="1" spacing="compact">
            <li>Consider if LLDP should be a recommended functionality for ANI devices
    to improve diagnostics, and if so, simple, self-managing protocol, which information elements does
	  not require zones or areas; it should
    signal (noting that such information is conveyed in also self-configuring, since
	  configuration is carried as part of the protocol (see <xref target="RFC6550" sectionFormat="of" section="6.7.6" format="default" derivedLink="https://rfc-editor.org/rfc/rfc6550#section-6.7.6" derivedContent="RFC6550"/>).</li>
          <li pn="section-a.4-3.2">Scale: the ACP builds over an insecure manner). Includes potentially new information elements.</li>
            <li>In alternative to LLDP, A DULL GRASP diagnostics objective entire domain, which could be defined to carry these information elements.</li>
            <li>The IDevID certificate a large enterprise or service provider network.  The routing protocol must therefore support domains of BRSKI pledges should be included in 100,000 nodes or more, ideally without the selected
    insecure diagnostics option. need for zoning or separation into areas.  RPL has this scale property.  This may be undesirable when exposure of device information is seen as too much of a security issue (ability to deduce possible attack vectors from device model for example).</li>
            <li>A richer set based on extensive use of diagnostics information should be made available
    via default routing.</li>
          <li pn="section-a.4-3.3">Low resource consumption: the secured ACP channels, using either single-hop GRASP or supports traditional network wide "topology discovery" mechanisms.</li>
          </ol>
        </section>

        <section anchor="compromised" numbered="true" toc="default">
          <name>Avoiding and dealing with compromised ACP nodes</name>
          <t>Compromised ACP nodes pose the biggest risk infrastructure, thus runs in addition to traditional protocols.  The ACP, and specifically the operations routing protocol, must have low resource consumption requirements, both in terms of memory and CPU.  Specifically, at edge nodes, where memory and CPU are scarce, consumption should be minimal.  RPL builds a DODAG, where the network.
The most common type of compromise main resource consumption is leakage at the root of credentials to manage/configure the device and DODAG.  The closer to the application edge of malicious configuration including the change
of access credentials, but not network, the change of software. Most of today's networking
equipment should have secure boot/software infrastructure anyhow, so attacks less state needs to be maintained.  This adapts nicely to the typical network design.  Also, all changes below a common parent node are kept below that introduce malicious software should parent node.</li>
          <li pn="section-a.4-3.4">Support for unstructured address space: in the ANI, node addresses are identifiers, they and may not be assigned in a lot harder.</t>
          <t>The most important aspect of security design against these type of attacks topological way.  Also, nodes may move topologically, without changing their address.  Therefore, the routing protocol must support completely unstructured address space.  RPL is
to eliminate password based configuration access methods and instead rely specifically made for mobile, ad hoc networks, with no assumptions on
certificate based credentials handed out only topologically aligned addressing.</li>
          <li pn="section-a.4-3.5">Modularity: to nodes where keep the initial implementation small, yet allow for more complex methods later, it is clear highly desirable that the private keys cannot leak. This limits unexpected propagation routing protocol has a simple base functionality, but can import new functional modules if needed.  RPL has this property with the concept of credentials.</t>
          <t>If password based credentials "Objective Function", which is a plugin to configure devices still need modify routing behavior.</li>
          <li anchor="extens" pn="section-a.4-3.6">Extensibility: since the ANI is a new concept, it is likely that changes to be supported, they must not be
locally configurable, but only be remotely provisioned or verified (through
protocols like RADIUS or Diameter), and there must be no local configuration
permitting the way of operation will happen over time.  RPL allows for new Objective Functions to change these authentication mechanisms, but ideally they should be autoconfiguring across the ACP. See <xref target="I-D.eckert-anima-noc-autoconfig" format="default"/>.</t>
          <t>Without physical access introduced later, which allow changes to the compromised device, attackers with access way the routing protocol creates the DAGs.</li>
          <li pn="section-a.4-3.7">Multi-topology support: it may become necessary in the future to
configuration support more than one DODAG for different purposes, using different Objective Functions.  RPL allow for the creation of several parallel DODAGs should not this be able required.  This could be used to break create different topologies to reach different roots.</li>
          <li pn="section-a.4-3.8">No need for path optimization: RPL does not necessarily compute the optimal path between any two nodes.  However, the ACP connectivity, even when they
can break or otherwise manipulate (spoof) the Data-Plane connectivity through configuration.
To achieve this, does not require this today, since it carries mainly delay-insensitive feedback loops.  It is possible that different optimization schemes will become necessary to avoid providing configuration options for in the
ACP, such as enabling/disabling it on interfaces. For example, there could future, but RPL can be an
ACP configuration that locks down the current ACP config unless factory reset expanded (see <xref target="extens" format="none" sectionFormat="of" derivedContent="">"Extensibility"</xref> above).</li>
        </ul>
      </section>
      <section anchor="acp-grasp" numbered="true" toc="include" removeInRFC="false" pn="section-a.5">
        <name slugifiedName="name-acp-information-distributio">ACP Information Distribution and Multicast</name>
        <t indent="0" pn="section-a.5-1">IP multicast is done.</t>
          <t>With such means, the valid administration has not used by the best chances to maintain
access to ACP nodes, discover malicious configuration though ongoing configuration
tracking from central locations for example, and to react accordingly.</t>
          <t>The primary reaction is withdrawal/change of credentials, terminate malicious
existing management sessions and fixing because the configuration. Ensuring that management
sessions using invalidated credentials are terminated automatically without recourse will
likely require new work.</t>
          <t>Only when these steps are ANI itself does not feasible require IP multicast
        but only service announcement/discovery.  Using IP multicast for that would have made it be
        necessary to revoke or expire the ACP certificate credentials and consider the node kicked off the network develop a zero-touch autoconfiguring solution for ASM (Any Source Multicast -
until the situation can original form of IP multicast defined in "<xref target="RFC1112" format="title" sectionFormat="of" derivedContent="Host extensions for IP multicasting"/>" <xref target="RFC1112" format="default" sectionFormat="of" derivedContent="RFC1112"/>), which
        would be further rectified, likely requiring direct physical access quite complex and difficult to the node.</t>
          <t>Without extensions, compromised ACP nodes can only be removed from the ACP justify.  One aspect of complexity
        where no attempt at a solution has been described
        in IETF documents is the speed automatic selection of CRL/OCSP information refresh or expiry (and non-removal)
        routers that should be PIM Sparse Mode (PIM-SM) Rendezvous Points (RPs) (see "<xref target="RFC7761" format="title" sectionFormat="of" derivedContent="Protocol Independent Multicast - Sparse Mode (PIM-SM): Protocol Specification (Revised)"/>" <xref target="RFC7761" format="default" sectionFormat="of" derivedContent="RFC7761"/>).  The other aspects of short lived  certificates. Future extensions to complexity
        are the ACP could for
example use GRASP flooding distribution of triggered updates of CRL/OCSP or
explicit removal indication implementation of the compromised nodes domain certificate.</t>
        </section>

        <section anchor="downgrade" numbered="true" toc="default">
          <name>Detecting ACP secure channel downgrade attacks</name>

          <t>The following text proposes MLD ("<xref target="RFC4604" format="title" sectionFormat="of" derivedContent="Using Internet Group Management Protocol Version 3 (IGMPv3) and Multicast Listener Discovery Protocol Version 2 (MLDv2) for Source-Specific Multicast"/>" <xref target="RFC4604" format="default" sectionFormat="of" derivedContent="RFC4604"/>), PIM-SM, and Anycast-RP (see "<xref target="RFC4610" format="title" sectionFormat="of" derivedContent="Anycast-RP Using Protocol Independent Multicast (PIM)"/>" <xref target="RFC4610" format="default" sectionFormat="of" derivedContent="RFC4610"/>).  If those implementations already
        exist in a mechanism product, then they would be very likely tied to protect against downgrade attacks without introducing a new specialized UPFRONT GRASP secure channel mechanism. Instead, it relies on running GRASP after establishing a secure channel protocol accelerated forwarding,
        which consumes hardware resources, and that in turn is difficult to verify if justify as a cost
        of performing only service discovery.</t>
        <t indent="0" pn="section-a.5-2">Some future ASA may need high-performance, in-network data replication.  That is the established secure channel option could have been case
        when the result use of a MITM downgrade attack:</t>

          <t>MITM attackers IP multicast is justified.  Such an ASA can force downgrade attacks for ACP secure channel selection by filtering/modifying DULL GRASP messages and/or actual secure channel data packets. For example, if at some point in time DTLS traffic could be easier decrypted than traffic of IKEv2, the MITM could filter all IKEv2 packets to force ACP nodes to then use DTLS (assuming the service discovery
        from ACP nodes in question supported both DTLS GRASP, and IKEv2).</t>
          <t>For cases where such MITM attacks are then they do not capable to inject malicious traffic (but need ASM but only to decrypt the traffic), a downgrade attack could be discovered after a secure channel connection is established, SSM (see "<xref target="RFC4607" format="title" sectionFormat="of" derivedContent="Source-Specific Multicast for IP"/>" <xref target="RFC4607" format="default" sectionFormat="of" derivedContent="RFC4607"/>)
        for example by use of the following type of mechanism:</t>
          <t>After the secure channel connection is established, IP multicast replication.  SSM itself can simply be enabled in the two ACP peers negotiate via data plane
        (or even in an appropriate (To Be Defined) GRASP negotiation which ACP secure channel protocol should have been selected between them (in update to the absence of ACP) without any configuration other than just enabling it
        on all nodes, and it only requires a MITM attacker). This negotiation would simpler version of MLD (see "<xref target="RFC5790" format="title" sectionFormat="of" derivedContent="Lightweight Internet Group Management Protocol Version 3 (IGMPv3) and Multicast Listener Discovery Version 2 (MLDv2) Protocols"/>" <xref target="RFC5790" format="default" sectionFormat="of" derivedContent="RFC5790"/>).</t>
        <t indent="0" pn="section-a.5-3">IGP routing protocols based on LSP (Link State Protocol) typically have a mechanism to signal the DULL
        flood information, and such a mechanism could be used to flood GRASP announced ACP secure channel options by each peer followed objectives by an announcement
        defining them to be information of the preferred secure channel protocol by the ACP peer that is the Decider IGP.  This would be a possible optimization
        in the secure channel setup, e.g. future variations of the ACP peer that is deciding which secure channel protocol to pick. If that chosen secure channel protocol is different from the one that actually was chosen, then this mismatch is do use an indication LSP-based routing protocol.  Note though that there is
        such a MITM attacker or other similar issue (firewall prohibiting mechanism would not work easily for GRASP M_DISCOVERY messages, which are intelligently
        (constrained) flooded not across the use of specific protocols) that caused a non-preferred secure channel protocol to be chosen. This discovery could then result in mitigation options such as logging and ensuing investigations.</t>
        </section>

      </section>
    </section>
    <!-- further considerations -->

    <section anchor="unfinished" numbered="true" toc="default">
      <name>Unfinished considerations (To Be Removed From RFC)</name>

        <t>[RFC-Editor: This whole appendix B. and its subsections ACP, but only up to be removed for the RFC.</t>

      <t>This appendix contains unfinished considerations a node where a responder is found.
        We expect that are removed from the RFC,
         they are maintained many future services in this draft as a log of the state of discussion ASA will have only a few consuming ASAs, and
         point of reference. Together with this appendix, also for those cases,
        the references pointing to
         it are marked to be removed from M_DISCOVERY method is more efficient than flooding across the RFC because no consensus could be reached that
         a self-reference to a draft version of whole domain.</t>
        <t indent="0" pn="section-a.5-4">Because the RFC ACP uses RPL, one desirable future extension is an appropriate breadcrumb
         to point to unfinished considerations.</t>

       <t>The authors plan use RPL's existing
        notion of DODAG, which are loop-free distribution trees, to move these considerations into a new target informational
         draft, please look make GRASP flooding more efficient
        both for draft-eckert-anima-acp-considerations.</t>

        <section anchor="ben-kaduk" numbered="true" toc="default">
          <name>Considerations M_FLOOD and M_DISCOVERY. See <xref target="ACP_interfaces" format="default" sectionFormat="of" derivedContent="Section 6.13.5"/> for improving secure channel negotiation</name>

          <t>Proposed text from Benjamin Kaduk. It how this will be
        specifically beneficial when using NBMA interfaces.  This
        is suggested to replace
          the text of appendix A.6 not currently specified in previous versions of this draft (up document because it is not quite clear yet what
        exactly the implications are to version 29).</t>

          <t>The discovery procedure in this specification for low-level ACP channel
          support by layer-2 peers involves DULL make GRASP flooding depend on RPL DODAG convergence
        and attempting (usually in
          parallel) how difficult it would be to establish all supported channel types, learning let GRASP flooding access the peer ACP
          address DODAG information.</t>
      </section>
      <section anchor="domain-usage" numbered="true" toc="include" removeInRFC="false" pn="section-a.6">
        <name slugifiedName="name-cas-domains-and-routing-sub">CAs, Domains, and correspondingly the assignment Routing Subdomains</name>
        <t indent="0" pn="section-a.6-1">There is a wide range of Decider and Follower roles, setting up different ACP solutions by appropriately using CAs and tearing down all channels other than the one preferred by domain and rsub elements in the Decider.
          This procedure, acp-node-name in general, becomes resource intensive as the number domain certificate.  We summarize these options here as they have been explained in different parts of the document and discuss possible secure channels grows; even worse, under some threat models, and desirable extensions.</t>
        <t indent="0" pn="section-a.6-2">An ACP domain is the
          security set of the discovery result is only as strong all ACP nodes that can authenticate each other as belonging to the weakest supported
          secure channel protocol.  Furthermore, the unilateral determination of
          "best" channel type by same ACP network using the Decider does not result in ACP domain membership check (<xref target="certcheck" format="default" sectionFormat="of" derivedContent="Section 6.2.3"/>).  GRASP inside the optimal outcome
          in all possible scenarios.</t>

          <t>This situation ACP is tolerable at present, with only two secure channels (DTLS
          and IPsec) defined, but long-term agility run across all transitively connected ACP nodes in a domain.</t>
        <t indent="0" pn="section-a.6-3">The rsub element in the vein of [BCP201] will
          require acp-node-name permits the introduction use of an alternate discovery/negotiation procedure.
          While IKEv2 addresses from different ULA prefixes.  One use case is the IETF standard protocol for negotiating security
          associations, it currently does not have a defined mechanism flexible
          enough to negotiate the parameters needed for, e.g., an ACP DTLS channel,
          let alone for allowing creation of multiple physical networks that initially may be separated with one ACP peers to indicate domain but different routing subdomains, so that all nodes can mutually trust their preference metrics for
          channel selection.  Such a mechanism or mechanisms ACP certificates (not depending on rsub) and so that they could be defined, but if connect later together into a contiguous ACP agility requires introducing network.</t>
        <t indent="0" pn="section-a.6-4">One instance of such a new channel type, for example MacSec,
          IKEv2 would again need to be extended in order to negotiate use case is an ACP MacSec
          association.  Making ACP channel agility dependent on updates to IKEv2 is
          likely to result in obstacles for regions interconnected via a non-ACP enabled core, for example, due to different timescales the absence of evolution,
          since IKEv2 implementations help form product support for ACP on the core of Internet-scale security
          infrastructure and must accordingly nodes. ACP connect configurations as defined in this document can be robust used to extend and thoroughly tested.</t>

          <t>Accordingly, a dedicated interconnect those ACP channel negotiation mechanism is appropriate
          as a way islands to provide long-term algorithm the NOC and secure-channel protocol
          agility.  Such merge them into a mechanism is not currently defined, but one possible
          design single ACP when later that product support gap is as follows.  A new DULL GRASP objective closed.</t>
        <t indent="0" pn="section-a.6-5">Note that RPL scales very well.  It is defined not necessary to indicate
          the GRASP-over-TLS channel, which is by definition preferred use multiple routing subdomains to scale ACP domains in a way that would be required if other
          channel types (including DTLS and IPsec).  When both peers advertise
          support routing protocols where used.  They exist only as options for GRASP-over-TLS, GRASP-over-TLS must run the above mentioned reasons.</t>
        <t indent="0" pn="section-a.6-6"> If ACP domains need to completion before be created that are not allowed to connect to each other channel types by default, simply use different domain elements in the acp-node-name.  These domain elements can be arbitrary, including subdomains of one another: domains "example.com" and "research.example.com" are separate domains if both are attempted.  The GRASP-over-TLS channel performs domain elements in the acp-node-name of certificates.</t>
        <t indent="0" pn="section-a.6-7">It is not necessary negotiation by establishing a TLS connection between the peers
          and using that connection to secure have a dedicated GRASP instance separate CA for
          negotiating supported channel types and preference metrics.  This provides different ACP domains: an operator can use a rich language for determining what secure channel protocol single CA to use sign certificates for multiple ACP domains that are not allowed to connect to each other because the checks for ACP link while taking into account adjacencies include the capabilities and preferences comparison of the domain part.</t>
        <t indent="0" pn="section-a.6-8">If multiple, independent networks chose the same domain name but had their own CAs, these would not form a single ACP peers, all protected domain because of CA mismatch.  Therefore, there is no problem in choosing domain names that are potentially also used by the security others.  Nevertheless, it is highly recommended to use domain names that have a high probability of being unique.  It is recommended to use domain names that start with a DNS domain name owned by the TLS channel.</t> assigning organization and unique within it, for example, "acp.example.com" if you own "example.com".</t>
      </section>
      <section anchor="verify-address" anchor="intent" numbered="true" toc="default">
  <name>ACP address verification</name>

  <t>The AcpNodeName of most ACP nodes contains in toc="include" removeInRFC="false" pn="section-a.7">
        <name slugifiedName="name-intent-for-the-acp">Intent for the acp-address field ACP</name>
        <t indent="0" pn="section-a.7-1">Intent is the
  primary ACP address architecture component of Autonomic Networks according to
 <xref target="RFC8993" format="default" sectionFormat="of" derivedContent="RFC8993"/> that allows operators to issue policies to be used by
the node network.  Its applicability for end-to-end connections use is quite  flexible and freeform, with potential applications including
policies flooded across ACP secure channels. Nevertheless, there GRASP and interpreted on every ACP node.</t>
        <t indent="0" pn="section-a.7-2">One concern for future definitions of Intent solutions is no verification the problem of an circular dependencies
when expressing Intent policies about the ACP peers address specified in this document. This section explains itself.</t>
        <t indent="0" pn="section-a.7-3">For example, Intent could indicate the
  current understanding as desire to why this is not done.</t>

  <t>Not all build an ACP nodes will across all domains
that have an actual IPv6 address a common parent domain (without relying on the rsub/routing-subdomain
solution defined in this document): ACP nodes with the acp-address field domains "example.com",
 "access.example.com", "core.example.com", and "city.core.example.com"
should all establish one single ACP.</t>
        <t indent="0" pn="section-a.7-4">If each domain has its own source of their AcpNodeName. Those who do not include nodes that do not support Intent, then the Intent would simply have to
allow adding the peer domain's TA and domain names to the parameters for the ACP secure channels, such as pre-existing NOC equipment domain membership check
(<xref target="certcheck" format="default" sectionFormat="of" derivedContent="Section 6.2.3"/>) so that nodes from those other domains are accepted as ACP peers.</t>
        <t indent="0" pn="section-a.7-5">If this Intent was to be originated only connects from one domain, it could likely not be made
to work because the other domains will not build any ACP via connections amongst each other,
whether they use the same or different CA due to the ACP connect interfaces. Likewise, future domain membership check.</t>
        <t indent="0" pn="section-a.7-6">If the  domains use the same CA, one could change the ACP setup to permit the
ACP node type that
  may want to have their Node-ID not be defined by an established between two ACP nodes with different acp-domain-names, but only
 for the purpose of disseminating limited information,
such as Intent, but not to set up full ACP connectivity, specifically not RPL routing
and passing of arbitrary GRASP information, unless the Intent policies permit this
 to happen across domain boundaries.</t>
        <t indent="0" pn="section-a.7-7">This type of approach, where the ACP registrar, but
  differently cannot have first allows Intent to operate and only then
sets up the rest of ACP address connectivity based on Intent policy, could also be provided in their ACP certificate
  where it used to
enable Intent policies that would be defined by limit functionality across the registrar. In result, any scheme that ACP inside a domain,
as long as no policy would rely on verification of disturb the acp-address in distribution of Intent, for example, to limit
reachability across the ACP certificate would
  only apply to a subset certain types of nodes or locations of ACP nodes.</t>

  <t>The transport stack network layer address used
      </section>
      <section anchor="reuse-acp" numbered="true" toc="include" removeInRFC="false" pn="section-a.8">
        <name slugifiedName="name-adopting-acp-concepts-for-o">Adopting ACP Concepts for Other Environments</name>
        <t indent="0" pn="section-a.8-1">The ACP secure channels as specified in this document is very explicit about the choice of options to
allow interoperable implementations.  The choices made may not be the best for all environments,
but the concepts used by the acp-address. For automatically established ACP secure channels,
  it is a link-local IPv6 address. For explicitly configured ACP secure
  channels (to reach across non can be used to build derived solutions.</t>
        <t indent="0" pn="section-a.8-2">The ACP L3 network segments), specifies the use of ULA and the derivation of its prefix from the domain name
so that no address allocation is required to deploy the ACP. The ACP will equally
work using any IPv4 or other /48 IPv6 address routable prefix and not ULA.  This prefix could simply be a configuration
of the ACP registrars (for example, when using BRSKI) to that remote destination.</t>

  <t>When enroll the acp-address is actually used across domain certificates, instead
of the ACP, ACP registrar deriving the /48 ULA prefix from the AN domain name.</t>
        <t indent="0" pn="section-a.8-3">Some solutions may already have an auto-addressing scheme, for example, derived from
existing, unique device identifiers (e.g., MAC addresses).  In those cases, it can only may not be verified by a peer when desirable
to assign addresses to devices via the peer has ACP address information field in the way described
in this document.  The certificate of the peer.
  Unless further higher layer mechanisms are developed on top of may simply serve to identify the ACP (for example via ASA), domain,
and the address field could be omitted. The only mechanism to access a peers fix required in the remaining
way the ACP
  certificate operates is for secure connections to define another element in which the domain certificate for
the two peers certificates
  are exchanged and cryptographically verified, e.g. TLS to decide who is the Decider and DTLS.
  Initially, it who is expected that the ACP will carry many legacy network
  management control connections that unfortunately not end-to-end
  authenticated but Follower during secure channel building.
Note though that are solely protected by being carried across future work may leverage the ACP secure channels. ACP address verification therefore cannot
  be used for such connections without additional higher layer components.</t>

  <t>For to authenticate "ownership"
of the remaining (TLS/DTLS) connections for which address verification
  can be used, by the main question is: what additional benefit would device.  If the ACP address
  verification provide?</t>

  <t>The main value used by a device is derived from some preexisting,
permanent local ID (such as MAC address), then it would be useful
to store that transport stack network layer address verification
  could provide for these type local ID also in the certificate.</t>
        <t indent="0" pn="section-a.8-4">The ACP is defined as a separate VRF because it intends to support well-managed
networks with a wide variety of connections configurations.  Therefore, reliable,
configuration-indestructible connectivity cannot be achieved from the data plane itself.
In solutions where all functions that impact transit connectivity are fully automated (including security),
indestructible, and resilient, it would be the discovery
  of on-path transport proxies. For example, in case of BRSKI,
  pledges connect possible to an eliminate the need for the ACP registrar via an ASA implementing to be a TCP
  proxy because separate VRF.
Consider the pledge itself has at that point most simple example system in time which there is no separate data plane, but the ACP certificate valid to build ACP secure channels and hence needs to
  rely on such a proxy. This is one example where such a TCP proxy is
  required the data plane.  Add
BRSKI, and not it becomes a form of attack.</t>

  <t>In general, on path TCP proxies could fully Autonomic Network -- except that it does not support
automatic addressing for user equipment.  This gap can then be closed, for example, by adding a form of attack, but it stands
solution derived from "<xref target="RFC8992" format="title" sectionFormat="of" derivedContent="Autonomic IPv6 Edge Prefix Management in Large-Scale Networks"/>" <xref target="RFC8992" format="default" sectionFormat="of" derivedContent="RFC8992"/>.</t>
        <t indent="0" pn="section-a.8-5">TCP/TLS as the protocols to reason, that an attacker that manages provide reliability and security to enable a malicious
  TCP proxy could likely equally build a transparent proxy not changing
  the network layer addresses. Only when GRASP in the attacker operates off-path
  would this option ACP
may not be possible. Such attacks could indeed the preferred choice in constrained networks. For example, CoAP/DTLS
(Constrained Application Protocol) may be possible:
  An impaired preferred where they are already used,
which would reduce the additional code space footprint for the ACP node could announce itself as another service instance on
those devices. Hop-by-hop reliability for a service whose utilization it wants to attack. It ACP GRASP messages could then attempt be made
to look support protocols like a valid server DTLS by simply TCP proxying adding the clients same type of
negotiation as defined in this document for ACP secure channel protocol negotiation.
In future ACP extensions meant to better support constrained devices,
end-to-end GRASP connections can be made to a valid server and then attack select their transport protocol
by indicating the connections
  passing supported transport protocols (e.g. TLS/DTLS) via GRASP parameters
of the GRASP objective through it (passive decrypting or passive fingerprint analysis).
  But like which the BRSKI proxy, this behavior could be
  perfectly legitimate and not an attack. For example, TCP has in transport endpoint is discovered.</t>
        <t indent="0" pn="section-a.8-6">RPL, the
  past often suffered from performance issues across difficult (high
  capacity, high loss) paths, and TCP proxies where and are being routing protocol used
  simply as a tool for isolating the ACP, explicitly does not optimize
for shortest paths and fastest convergence.  Variations of the ACP may want to use a
different routing protocol or introduce more advanced RPL profiles.</t>
        <t indent="0" pn="section-a.8-7">Variations such path segments (such as which routing protocol to use, or whether to instantiate an ACP
in a WAN),
  and providing caching and local-retransmit of in-transit packets,
  reducing VRF or (as suggested above) as the effective path segment capacity.</t>

  <t>As explained elsewhere actual data plane, can be automatically chosen
in this document already, considerations for implementations built to support multiple options by deriving them from future parameters
in the certificate.  Parameters in certificates should be limited to those that would
not need to be changed more often than that certificates would need to be updated,
or it should be ensured that these type parameters can be provisioned before the
variation of attack are therefore outside an ACP is activated in a node.  Using BRSKI, this could be done, for example,
as additional follow-up signaling directly after the scope of certificate enrollment, still
leveraging the ACP BRSKI TLS connection and therefore not introducing any additional
connectivity requirements.</t>
        <t indent="0" pn="section-a.8-8">Last but
  fundametal not least, secure channel protocols including their encapsulations are
easily added to further design of ACP solutions.  ACP hop-by-hop network-layer secure channels could
also be replaced by end-to-end security plus other means for infrastructure
protection.  Any future network OAM should always use end-to-end security. By
leveraging the ASA infrastructure. Beyond
  distinguishing whether a TCP proxy domain certificates, it would not be beneficial or malicious, dependent on security
provided by ACP secure channels.</t>
      </section>
      <section anchor="futures" numbered="true" toc="include" removeInRFC="false" pn="section-a.9">
        <name slugifiedName="name-further-future-options">Further (Future) Options</name>
        <section anchor="auto-aggregation" numbered="true" toc="include" removeInRFC="false" pn="section-a.9.1">
          <name slugifiedName="name-auto-aggregation-of-routes">Auto-Aggregation of Routes</name>
          <t indent="0" pn="section-a.9.1-1">Routing in the even more fundamental question is how ACP according to determine from a multitude
  of service announcements which instance is the most trustworthy and
  functionally best. In the Internet/web, this question is NOT solved
  inside specification only leverages the network but through off-net human interaction ("trust me,
standard RPL mechanism of route optimization, e.g., keeping only the best search engine is www.&lt;insert-your-personal-recommendation>.com").</t>
</section>

<section anchor="public-ca" numbered="true" toc="default">
  <name>Public CA considerations</name>

  <t>Public CAs routes that
are outside not towards the scope RPL root. This is known to scale to networks with 20,000 or more nodes.
There is no auto-aggregation of this document routes for /48 ULA prefixes (when using rsub
in the following reasons. This appendix describes the current state acp-node-name) and/or Zone-ID based prefixes.</t>
          <t indent="0" pn="section-a.9.1-2">Automatic assignment of understanding for those interested to consider utilizing public CA Zone-ID and auto-aggregation of routes could
be achieved, for example, by configuring zone boundaries, announcing via GRASP
into the ACP in zones the future.</t>

  <t>If public CA where to be used to enroll ACP nodes zone parameters (Zone-ID and act as TA, this would require a model in which /48 ULA prefix), and auto-aggregating
routes on the public CA zone boundaries. Nodes would be able to assert assign their Zone-ID and potentially
even the ownership of /48 prefix based on the information requested GRASP announcements.</t>
        </section>
        <section anchor="dp-dependency" numbered="true" toc="include" removeInRFC="false" pn="section-a.9.2">
          <name slugifiedName="name-more-options-for-avoiding-i">More Options for Avoiding IPv6 Data Plane Dependencies</name>
          <t indent="0" pn="section-a.9.2-1">As described in <xref target="general_addressing" format="default" sectionFormat="of" derivedContent="Section 6.13.2"/>, the certificate,
  especially the AcpNodeName, for example mitigated by ACP depends on the domain registrar(s).
  Due
data plane to the use of establish IPv6 link-local addressing on interfaces. Using a new, separate
MAC address for the ACP unique encoding of allows the AcpNodeName,
  there is no mechanism for public CA to do so. More importantly though, full isolation between
  ACPs of disjoint operated ACPs is achieved in the current ACP design through disjoint TA.
  A public CA is from the data plane in general based on
a single (set of) TA shared across all certificates signed by the CA.</t>

  <t>Due to the fact way that the ACP domain membership check is compatible with this specification. It is also validates that a peers domain name an ideal option
when using single-root input/output virtualization (SR-IOV, see
<xref target="SR" format="default" sectionFormat="of" derivedContent="SR"/>)
 in the AcpNodeName matches that of the ACP node itself, it would be possible an implementation to use isolate the same
  TA across disjoint ACP domains, but the security and attack implications of such an approach
  are beyond the scope of this document.</t>

  <t>The because
different SR-IOV interfaces use of ULA addresses in the AcpNodeName is another novel aspect for certificates
  from a possible public CA.  Typically, ULA addresses different MAC addresses.</t>
          <t indent="0" pn="section-a.9.2-2">When additional MAC address(es) are not meant to be signed by a public CA when
  carried in an address field, because there is no ownership of a particular
  ULA address in the scope available, separation of the Internet, which is what public CA operate on.
  Nevertheless, the ULA addresses used by the
ACP are scoped to could be valid only within
  the confines of done at different demux points. The same subnet interface could have
a specific separate IPv6 interface for the ACP as defined by and data plane and therefore separate
link-local addresses for both, where the domain name in ACP interface is not configurable on
the AcpNodeName.
  However, data plane. This too would be compatible with this understanding has specification and not been reviewed or accepted by any bodies
  responsible for policies of public CA.</t>

  <t>Because in this specification, ACPs are isolated from each other primarily by their TA,
  when a public CA
impact interoperability.</t>
          <t indent="0" pn="section-a.9.2-3">An option that would intend require additional specification is to sign ACP certificates and using use a single TA to sign
  TA of ACP certificates from different operators/domain, it could do so by ensuring that
  the domain name in
Ethertype from 0x86DD (IPv6) to encapsulate IPv6 packets for the AcpNodeName was ACP. This would
be a globally owned DNS ACP domain name
  of similar approach as used for IP authentication packets in <xref target="IEEE-802.1X" format="default" sectionFormat="of" derivedContent="IEEE-802.1X"/>,
which uses the organization, and beyond that, it would need to validate Extensible Authentication Protocol over Local Area Network (EAPoL)
Ethertype (0x88A2).</t>
          <t indent="0" pn="section-a.9.2-4">Note that in the ACP registrar case of ANI nodes, all of that domain who is mitigating the enrollment is authorized above considerations equally
apply to vouch for the ownership encapsulation of BRSKI packets including GRASP used for BRSKI.</t>
        </section>
        <section anchor="acp-api" numbered="true" toc="include" removeInRFC="false" pn="section-a.9.3">
          <name slugifiedName="name-acp-apis-and-operational-mo">ACP APIs and Operational Models (YANG)</name>
          <t indent="0" pn="section-a.9.3-1">Future work should define a YANG data model <xref target="RFC7950" format="default" sectionFormat="of" derivedContent="RFC7950"/>
and/or node-internal APIs to monitor and manage the acp-address within the scope of ACP.</t>
          <t indent="0" pn="section-a.9.3-2">Support for the ACP domain name.</t> adjacency table (<xref target="adj-table" format="default" sectionFormat="of" derivedContent="Section 6.3"/>) and ACP GRASP needs to
be included in such model and/or API.</t>
        </section>
        <section anchor="hardening" anchor="future-rpl" numbered="true" toc="default">
  <name>Hardening DULL GRASP considerations</name>

<t>DULL GRASP suffers from similar type of DoS attacks as many
link-local multicast discovery protocols, toc="include" removeInRFC="false" pn="section-a.9.4">
          <name slugifiedName="name-rpl-enhancements">RPL Enhancements</name>
          <figure anchor="dual-noc" align="left" suppress-title="false" pn="figure-17">
            <name slugifiedName="name-dual-noc">Dual NOC</name>
            <artwork name="" type="" align="left" alt="" pn="section-a.9.4-1.1">

   ..... USA ......              ..... Europe ......

        NOC1                           NOC2
         |                              |
         |            metric 100        |
       ACP1 --------------------------- ACP2  .
         |                              |     . WAN
         | metric 10          metric 20 |     . Core
         |                              |     .
       ACP3 --------------------------- ACP4  .
         |            metric 100        |
         |                              |     .
         |                              |     . Sites
       ACP10                           ACP11  .

</artwork>
          </figure>
          <t indent="0" pn="section-a.9.4-2">The profile for example mDNS.
Attackers on RPL specified in this document builds only one spanning-tree path set to a subnet root, typically a registrar in one NOC. In the presence of multiple NOCs, routing toward the non-root NOCs may be able to inject malicious DULL GRASP
messages that are indistinguishable from non-malicious DULL GRASP
messages to create Denial-of-Service (DoS) attacks that force ACP
nodes to attempt many unsuccessful ACP secure channel connections.</t>

<t>When suboptimal. <xref target="dual-noc" format="default" sectionFormat="of" derivedContent="Figure 17"/> shows an ACP extreme example. Assuming that node sees multiple AN_ACP objectives for the same secure
channel protocol on different transport addresses, it could prefer
connecting via ACP1 becomes the well-known transport address if RPL root, traffic between ACP11 and NOC2 will pass through ACP4-ACP3-ACP1-ACP2 instead of ACP4-ACP2 because the secure channel
method has one, such as UDP port 500 for IKEv2. For protocols such as
(ACP secure channel over) DTLS for which there RPL-calculated DODAG and routes are no well defined port
number, this heuristic does not provide benefits though.</t>

<t>DoS attack with port numbers can also be eliminated by relying
on well known-port numbers implied by shortest paths towards the GRASP method-name. For
example, a future service name RPL root.</t>
          <t indent="0" pn="section-a.9.4-3">To overcome these limitations, extensions and/or modifications to the RPL profile can optimize for multiple NOCs.  This requires utilizing data plane artifacts, including IP-in-IP encapsulation/decapsulation on ACP routers and processing of "DTLSacp" IPv6 RPI headers.  Alternatively, (Src,Dst) routing table entries could be defined to used.</t>
          <t indent="0" pn="section-a.9.4-4">Flooding of ACP GRASP messages can be associated further constrained and therefore optimized by flooding only via links that are part of the RPL DODAG.</t>
        </section>
        <section anchor="role-assignments" numbered="true" toc="include" removeInRFC="false" pn="section-a.9.5">
          <name slugifiedName="name-role-assignments">Role Assignments</name>
          <t indent="0" pn="section-a.9.5-1">ACP connect is an explicit mechanism to "leak" ACP traffic explicitly (for example,
in a newly NOC). It is therefore also a possible security gap when it is easy to be assigned well known UDP port for enable ACP
over DTLS, and the port number
 connect on arbitrary compromised ACP nodes.</t>
          <t indent="0" pn="section-a.9.5-2">One simple solution is to define an extension in the GRASP transport address ACP certificate's ACP information would
field indicating the permission for ACP connect to be ignored. Note configured on that there is already
a variety of ports assigned to specific protocols over DTLS by IANA,
so especially for DTLS this would not ACP node. This
could similarly be uncommon.</t>

</section>

    </section>
    <!-- unfinished considerations -->

  </back>
</rfc>
<!-- REMOVED this section in version 12 due done to feedback by working group
     (Michael Richardson).  Let IETF feedback decide if this additional text whether a node is necessary

        <section anchor="up4291" title="RFC4291/RFC4193 Updates Considerations">

<t>This document may be considered permitted to be updating a registrar or not.</t>
          <t indent="0" pn="section-a.9.5-3">Tying the IPv6 addressing architecture
(<xref target="RFC4291"/>) and/or permitted "roles" of an ACP node to the Unique Local IPv6 Unicast addresses (<xref target="RFC4193"/>)
depending on how strict specific statements in those specs are ACP certificate provides
fairly strong protection against misconfiguration, but it is still subject to be interpreted. code
modifications.</t>
          <t indent="0" pn="section-a.9.5-4">Another interesting role to assign to certificates is that of a NOC node. This section summarized and explains would allow the necessity and benefits of these changes.  The normative
parts
limiting of this document cover the actual updates.</t>

<t>ACP addresses (<xref target="addressing"/>) are used by network nodes supporting the ACP.  They are
assigned during bootstrap certain types of connections, such as OAM TLS connections to only the nodes NOC initiators
or initial provisioning of responders.</t>
        </section>
        <section anchor="l3-transit" numbered="true" toc="include" removeInRFC="false" pn="section-a.9.6">
          <name slugifiedName="name-autonomic-l3-transit">Autonomic L3 Transit</name>
          <t indent="0" pn="section-a.9.6-1">In this specification, the ACP.  They
are encoded in ACP can only establish autonomic connectivity across L2
hops  but requires non-autonomic configuration to tunnel across L3 paths. Future work should
specify mechanisms to automatically tunnel ACP across L3 networks. A hub-and-spoke
option would allow tunneling across the Domain Certificate Internet to a cloud or central instance of the node  and are primarily used internally
within the node.  In ACP;
a peer-to-peer tunneling mechanism could tunnel ACP islands across an L3VPN infrastructure.</t>
        </section>
        <section anchor="future-diag" numbered="true" toc="include" removeInRFC="false" pn="section-a.9.7">
          <name slugifiedName="name-diagnostics">Diagnostics</name>
          <t indent="0" pn="section-a.9.7-1"><xref target="diagnostics" format="default" sectionFormat="of" derivedContent="Section 9.1"/> describes diagnostics options that role they can be thought applied
without changing the external, interoperability-affecting characteristics of as Loopback addresses.</t>

<t>Each ACP domain assigns ACP addresses from one or more ULA prefixes.
Within an implementations.</t>
          <t indent="0" pn="section-a.9.7-2">Even better diagnostics of ACP network, addresses operations are assigned by nodes called registrars.
A unique Registrar-ID(entifier) possible with additional
signaling extensions, such as the following:</t>
          <ol type="1" spacing="normal" indent="adaptive" start="1" pn="section-a.9.7-3">
            <li pn="section-a.9.7-3.1" derivedCounter="1.">Consider if LLDP should be a recommended functionality for ANI devices
    to improve diagnostics, and if so, which information elements it should
    signal (noting that such information is used conveyed in ACP addresses an insecure manner). This includes potentially new information elements.</li>
            <li pn="section-a.9.7-3.2" derivedCounter="2.">As an alternative to allow multiple registrars LLDP, a DULL GRASP diagnostics objective could
    be defined to carry these information elements.</li>
            <li pn="section-a.9.7-3.3" derivedCounter="3.">The IDevID certificate of BRSKI pledges should be included in the selected
    insecure diagnostics option. This may be undesirable when exposure of device information is seen as too much of a security issue (the ability to assign addresses autonomically and uncoordinated from each other.  Typically these
Registrar-IDs are derived deduce possible attack vectors from the IEEE 802 48-bit MAC addresses device model, for example).</li>
            <li pn="section-a.9.7-3.4" derivedCounter="4.">A richer set of registrars.</t>

<t>In diagnostics information should be made available
    via the secured ACP Zone Addressing Sub-Scheme (<xref target="zone-scheme"/>), the registrar assigns
a unique 15-bit value to an channels, using either single-hop GRASP or
    network-wide "topology discovery" mechanisms.</li>
          </ol>
        </section>
        <section anchor="compromised" numbered="true" toc="include" removeInRFC="false" pn="section-a.9.8">
          <name slugifiedName="name-avoiding-and-dealing-with-c">Avoiding and Dealing with Compromised ACP node.  The Nodes</name>
          <t indent="0" pn="section-a.9.8-1">Compromised ACP address has a 64-bit Node-ID(entifier)
composed of the 48-bit Registrar-ID, nodes pose the registrar assigned 15-bit Node-Number and 1 V(irtualization)
bit that allows for an ACP node biggest risk to have two addresses.</t>

<t>The 64-bit Node-Identifier in the ACP Zone Addressing Sub-Scheme matches operations of the 64-bit
Interface Identifier (IID) address part as specified in RFC4291 section 2.5.1.
IIDs network.
The most common types of compromise are unique across ACP nodes, but all ACP nodes with the same ULA prefix
that use leakage of credentials to manage and/or configure
the ACP Zone Addressing Sub-Scheme will share device and the same subnet prefix
(according to application of malicious configuration, including the definition change
of access credentials, but not the change of software. Most of today's networking
equipment should have secure boot/software infrastructure anyhow, so attacks
that term in RFC4291).  Each ACP node injects introduce malicious software should be a /127
route into lot harder.</t>
          <t indent="0" pn="section-a.9.8-2">The most important aspect of security design against these types of attacks is
to eliminate password-based configuration access methods and instead rely on
certificate-based credentials handed out only to nodes where it is clear that
the ACP routing table private keys cannot leak. This limits unexpected propagation of credentials.</t>
          <t indent="0" pn="section-a.9.8-3">If password-based credentials to cover its two assigned addresses (V(irtual) bit being 0 configure devices still need to be supported, they must not be
locally configurable, but only be remotely provisioned or 1).
This approach is used because these ACP addresses are identifiers verified (through
protocols like RADIUS or Diameter), and there must be no local configuration
permitting the change of these authentication mechanisms, but ideally they should
be autoconfiguring across the ACP. See <xref target="I-D.eckert-anima-noc-autoconfig" format="default" sectionFormat="of" derivedContent="NOC-AUTOCONFIG"/>.</t>
          <t indent="0" pn="section-a.9.8-4">Without physical access to the compromised device, attackers with access to
configuration should not locators.  The be able to break the ACP node connectivity, even when they
can connect anywhere in break or otherwise manipulate (spoof) the ACP domain without having to change its addresses.  The lightweight,
highly scaleable routing protocol RPL data plane connectivity through configuration.
To achieve this, it is used necessary to allow avoid providing configuration options for large scale the
ACP, such as enabling/disabling it on interfaces. For example, there could be an
ACP networks.</t>

<t>It is possible, configuration that this scheme constitutes an update to RFC4191 because locks down the
same 64-bit subnet prefix is used across many ACP nodes.  The current ACP Zone Addressing
Sub-Scheme configuration unless factory reset is very similar to done.</t>
          <t indent="0" pn="section-a.9.8-5">With such means, the common operational practices of assigning /128
Loopback addresses valid administration has the best chances to network nodes maintain
access to ACP nodes, to discover malicious configuration though ongoing configuration
tracking from the same /48 central locations, for example, and to react accordingly.</t>
          <t indent="0" pn="section-a.9.8-6">The primary reaction is to withdraw or /64 subnet prefix.</t>

<t>In change credentials, terminate malicious
existing management sessions, and fix the ACP Vlong Addressing Sub-Scheme (<xref target="Vlong"/>), configuration. Ensuring that management
sessions using invalidated credentials are terminated automatically without recourse will
likely require new work.</t>
          <t indent="0" pn="section-a.9.8-7">Only when these steps are infeasible, would it be necessary
to revoke or expire the address elements
are ACP certificate credentials and consider the same as described for node kicked off the Zone Addressing Sub-Scheme, but network
until the V field is
expanded from 1-bit situation can be further rectified, likely requiring direct physical access to 8 or 16-bits.  The ACP node with the node.</t>
          <t indent="0" pn="section-a.9.8-8">Without extensions, compromised ACP Vlong addressing therefore injects
/120 or /112 prefixes into nodes can only be removed from the ACP routing table to cover its internal addresses.</t>

<t>The goal for
at the 8 speed of CRL/OCSP information refresh or 16-bit addresses available expiry (and non-removal)
of short-lived  certificates. Future extensions to an the ACP node in this scheme
is to assign them as required to software components, which in autonomic networking
are called ASA (Autonomic Service Agents).  It could equally be used could, for existing
software components such as VNFs (Virtual Networking Functions).  The ACP interface would
then be
example, use the out-of-band management interface GRASP flooding distribution of such a VNF software component.
It should especially be possible to use these software components in a variety triggered updates of contexts
to allow standardized modular system composition: Native applications (in some VRF context if available),
containers, virtual machines or other future ones.  To modularily compose a system with containers
and virtual machines and avoid problems such as port space collision CRL/OCSP or NAT, it is necessary not
only to assign separate addresses to those contexts, but also to use
the notion explicit removal indication of virtual
 interfaces between these contexts to compose the system.</t>

<t>In practical terms, the compromised node's domain certificate.</t>
        </section>
        <section anchor="downgrade" numbered="true" toc="include" removeInRFC="false" pn="section-a.9.9">
          <name slugifiedName="name-detecting-acp-secure-channe">Detecting ACP should be enabled to create from its /8 or /16
prefix one or more node internal virtual subnets and to start software components
connected to those virtual subnets.  Ideally, these software components should be
able Secure Channel Downgrade Attacks</name>
          <t indent="0" pn="section-a.9.9-1">The following text proposes a mechanism to auto configure their addresses protect against downgrade attacks without introducing a new specialized GRASP secure channel mechanism. Instead, it relies on these virtual interfaces.  Future work
has running GRASP after establishing a secure channel protocol to determine whether this address auto configuration for the virtual interface
is best done with DHCPv6, verify if SLAAC should be recommended the established secure channel option could have been the result of a MITM downgrade attack.</t>
          <t indent="0" pn="section-a.9.9-2">MITM attackers can force downgrade attacks for these /8 or /16 virtual
interfaces, or ACP secure channel selection by filtering and/or modifying DULL GRASP messages and/or actual secure channel data packets. For example, if at some additional standardized method would point in time, DTLS traffic could be required.</t>

<t>In more easily decrypted than traffic of IKEv2, the MITM could filter all IKEv2 packets to force ACP Vlong Addressing scheme, nodes to use DTLS (assuming that the Node-ID does ACP nodes in question supported both DTLS and IKEv2).</t>
          <t indent="0" pn="section-a.9.9-3">For cases where such MITM attacks are not match capable of injecting malicious traffic (but only of decrypting the RFC4291/RFC4193
64-bith length traffic), a downgrade attack could be discovered after a secure channel connection is established, for example, by using the Interface Identifier, so this addressing Sub-Scheme
in following type of mechanism.</t>
          <t indent="0" pn="section-a.9.9-4">After the ACP secure channel connection is established, the two ACP peers negotiate, via an update to both standards.</t>

<t>This document also specifies appropriate (to be defined) GRASP negotiation, which ACP secure channel protocol should have been selected between them (in the workaround solution absence of exposing a MITM attacker). This negotiation would signal the ACP
on native interfaces in support of adoption secure channel options announced by DULL GRASP by each peer followed by existing hardware and software
solutions.  A NOC based NMS host could for example be configured with a second
native interface connecting to an announcement of the preferred secure channel protocol by the ACP node peer that exposes is the Decider in the secure channel setup, i.e., the ACP peer that decides which secure channel protocol to use.  If that NMS
host (called ACP edge node).  The desired evolution of chosen secure channel protocol is different from the one that actually was chosen, then this workaround mismatch is an indication that
those two functions would merge into there is a single node, for example by making the ACP
router MITM attacker or other similar issue (e.g., a container/virtual machine inside firewall prohibiting the NMS host or vice versa.  The addressing
for those native interfaces allows for manually configured address prefixes but
it could use of specific protocols) that caused a non-preferred secure channel protocol to be fully autonomous if it chosen. This discovery could leverage the Vlong addressing format.  That would then result in a non /64 IID boundary on those external interfaces (but instead in /112 or
/120 subnet prefixes).</t>

<t>Note that both in the internal as well mitigation options such as logging and ensuing investigations.</t>
        </section>
      </section>
    </section>
    <section anchor="ack" numbered="false" toc="include" removeInRFC="false" pn="section-appendix.b">
      <name slugifiedName="name-acknowledgements">Acknowledgements</name>
      <t indent="0" pn="section-appendix.b-1">This work originated from an Autonomic Networking project at Cisco
      Systems, which started in early 2010. Many people contributed to this project and the workaround external use idea of ACP
addresses, all ACP addresses are meant the Autonomic Control Plane, amongst whom (in alphabetical order): <contact fullname="Ignas Bagdonas"/>, <contact fullname="Parag Bhide"/>, <contact fullname="Balaji BL"/>, <contact fullname="Alex Clemm"/>, <contact fullname="Yves Hertoghs"/>, <contact fullname="Bruno Klauser"/>, <contact fullname="Max Pritikin"/>, <contact fullname="Michael Richardson"/>, and <contact fullname="Ravi Kumar Vadapalli"/>.</t>
      <t indent="0" pn="section-appendix.b-2">Special thanks to be used exclusively by components that
are part of network control <contact fullname="Brian Carpenter"/>, <contact fullname="Elwyn Davies"/>, <contact fullname="Joel Halpern"/>, and OAM, but not <contact fullname="Sheng Jiang"/> for network users such as normal hosts.
This implies that their thorough reviews.</t>
      <t indent="0" pn="section-appendix.b-3">Many thanks to <contact fullname="Ben Kaduk"/>, <contact fullname="Roman Danyliw"/>, and <contact fullname="Eric Rescorla"/> for example no requirements their thorough SEC AD reviews, <contact fullname="Russ Housley"/> and <contact fullname="Erik Kline"/> for privacy addressing have
been identified their reviews, and to <contact fullname="Valery Smyslov"/>, <contact fullname="Tero Kivinen"/>, <contact fullname="Paul Wouters"/>, and <contact fullname="Yoav Nir"/> for ACP addresses.</t> review of IPsec and IKEv2 parameters and helping to understand those and other security protocol details better. Thanks to <contact fullname="Carsten Bormann"/> for CBOR/CDDL help.</t>
      <t indent="0" pn="section-appendix.b-4">Further input, review, or suggestions were received from <contact fullname="Rene Struik"/>, <contact fullname="Benoit Claise"/>, <contact fullname="William Atwood"/>, and <contact fullname="Yongkang Zhang"/>.</t>
    </section>
    <section anchor="contributors" numbered="false" toc="include" removeInRFC="false" pn="section-appendix.c">
      <name slugifiedName="name-contributors">Contributors</name>
      <t indent="0" pn="section-appendix.c-1">For all things GRASP including validation code, ongoing document text support, and technical input:</t>
      <contact fullname="Brian Carpenter" initials="B. E." surname="Carpenter">
        <organization abbrev="Univ. of Auckland" showOnFrontPage="true"/>
        <address>
          <postal>
            <street>School of Computer Science</street>
            <street>University of Auckland</street>
            <street>PB 92019</street>
            <city>Auckland</city>
            <code>1142</code>
            <country>New Zealand</country>
          </postal>
          <email>brian.e.carpenter@gmail.com</email>
        </address>
      </contact>
      <t indent="0" pn="section-appendix.c-2">For RPL contributions and all things BRSKI/bootstrap including validation code, ongoing document text support, and technical input:</t>
      <contact fullname="Michael C. Richardson" initials="M." surname="Richardson">
        <organization abbrev="Sandelman" showOnFrontPage="true">Sandelman Software Works</organization>
        <address>
          <email>mcr+ietf@sandelman.ca</email>
          <uri>http://www.sandelman.ca/mcr/</uri>
        </address>
      </contact>
      <t indent="0" pn="section-appendix.c-3">For the RPL technology choices and text:</t>
      <contact initials="P" surname="Thubert" fullname="Pascal Thubert">
        <organization abbrev="Cisco Systems" showOnFrontPage="true">Cisco Systems, Inc</organization>
        <address>
          <postal>
            <street>Building D</street>
            <street>45 Allee des Ormes - BP1200</street>
            <city>Mougins - Sophia Antipolis</city>
            <code>06254</code>
            <country>France</country>
          </postal>
          <phone>+33 497 23 26 34</phone>
          <email>pthubert@cisco.com</email>
        </address>
      </contact>
    </section>
    <section anchor="authors-addresses" numbered="false" removeInRFC="false" toc="include" pn="section-appendix.d">
      <name slugifiedName="name-authors-addresses">Authors' Addresses</name>
      <author role="editor" fullname="Toerless Eckert" surname="Eckert">
        <organization abbrev="Futurewei USA" showOnFrontPage="true">Futurewei Technologies Inc. USA</organization>
        <address>
          <postal>
            <street>2330 Central Expy</street>
            <city>Santa Clara</city>
            <region>CA</region>
            <code>95050</code>
            <country>United States of America</country>
          </postal>
          <email>tte+ietf@cs.fau.de</email>
        </address>
      </author>
      <author role="editor" fullname="Michael H. Behringer" initials="M." surname="Behringer">
        <address>
          <email>michael.h.behringer@gmail.com</email>
        </address>
      </author>
      <author fullname="Steinthor Bjarnason" initials="S." surname="Bjarnason">
        <organization showOnFrontPage="true">Arbor Networks</organization>
        <address>
          <postal>
            <street>2727 South State Street, Suite 200</street>
            <city>Ann Arbor</city>
            <region>MI</region>
            <code>48104</code>
            <country>United States of America</country>
          </postal>
          <email>sbjarnason@arbor.net</email>
        </address>
      </author>
    </section>
-->
  </back>
</rfc>