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    <front>

     <!--title abbrev="Abbreviated Title">SRv6
     <title abbrev="SRv6 Network Programming</title> -->
     <title>SRv6 Programming">Segment Routing over IPv6 (SRv6) Network Programming</title>
     <seriesInfo name="RFC" value="8986"/>

    <author fullname="Clarence Filsfils" initials="C." surname="Filsfils" role="editor">
      <organization>Cisco Systems, Inc.</organization>
      <address>
        <postal>
                <street></street>
                <city></city>
                <region></region>
                <code></code>
          <street/>
          <city/>
          <region/>
          <code/>
          <country>Belgium</country>
        </postal>
            <phone></phone>
        <phone/>
        <email>cf@cisco.com</email>
      </address>
    </author>
    <author fullname="Pablo Camarillo Garvia" initials="P." surname="Camarillo" role="editor" > role="editor">
      <organization>Cisco Systems, Inc.</organization>
      <address>
        <postal>
                <street></street>
                <city></city>
                <region></region>
                <code></code>
          <street/>
          <city/>
          <region/>
          <code/>
          <country>Spain</country>
        </postal>
        <email>pcamaril@cisco.com</email>
      </address>
    </author>
    <author fullname="John Leddy" initials="J." surname="Leddy">
        <organization>Individual Contributor</organization>
      <organization>Akamai Technologies</organization>
      <address>
        <postal>
                <street></street>
                <city></city>
                <region></region>
                <code></code>
          <street/>
          <city/>
          <region/>
          <code/>
          <country>United States of America</country>
        </postal>
        <email>john@leddy.net</email>
      </address>
    </author>
    <author fullname="Daniel Voyer" initials="D." surname="Voyer">
      <organization>Bell Canada</organization>
      <address>
        <postal>
                <street></street>
                <city></city>
                <region></region>
                <code></code>
          <street/>
          <city/>
          <region/>
          <code/>
          <country>Canada</country>
        </postal>
        <email>daniel.voyer@bell.ca</email>
      </address>
    </author>
    <author fullname="Satoru Matsushima" initials="S." surname="Matsushima">
      <organization abbrev="SoftBank">SoftBank</organization>
      <address>
        <postal>
                 <street>1-9-1,Higashi-Shimbashi,Minato-Ku</street>
                 <city>Tokyo  105-7322</city>
                 <region></region>
                 <code></code>

          <country>Japan</country>
        </postal>
             <phone></phone>
        <phone/>
        <email>satoru.matsushima@g.softbank.co.jp</email>
      </address>
    </author>
    <author fullname="Zhenbin Li" initials="Z." surname="Li">
      <organization>Huawei Technologies</organization>
      <address>
        <postal>
                <street></street>
                <city></city>
                <region></region>
                <code></code>
          <street/>
          <city/>
          <region/>
          <code/>
          <country>China</country>
        </postal>
            <phone></phone>
        <phone/>
        <email>lizhenbin@huawei.com</email>
      </address>
    </author>
    <date year="2021" month="February" />
    <area>General</area>
    <workgroup>SPRING</workgroup>
    <keyword>SRv6</keyword>
    <keyword>Segment Routing</keyword>
    <keyword>IPv6 Segment Routing</keyword>

     <!-- Keywords will be incorporated into HTML output
        files in a meta tag but they have no effect on text or nroff
        output. If you submit your draft to the RFC Editor, the
        keywords will be used for the search engine. -->

        <abstract>
      <t>The SRv6 Segment Routing over IPv6 (SRv6) Network Programming framework enables a
      network operator or an application to specify a packet processing
      program by encoding a sequence of instructions in the IPv6 packet
      header.</t>
      <t>Each instruction is implemented on one or several nodes in the
      network and identified by an SRv6 Segment Identifier in the packet.</t>
      <t>This document defines the SRv6 Network Programming concept and
      specifies the base set of SRv6 behaviors that enables the creation of
      interoperable overlays with underlay optimization.</t>
    </abstract>
  </front>
  <middle>
    <section title="Introduction"> numbered="true" toc="default">
      <name>Introduction</name>

      <t>Segment Routing <xref target="RFC8402" /> format="default"/> leverages
      the source routing paradigm. An ingress node steers a packet through an
      ordered list of instructions, called segments. "segments". Each one of these
      instructions represents a function to be called at a specific location
      in the network. A function is locally defined on the node where it is
      executed and may range from simply moving forward in the Segment List segment list to
      any complex user-defined behavior. Network programming Programming combines segment routing Segment
      Routing functions, both simple and complex, to achieve a networking
      objective that goes beyond mere packet routing.</t>
      <t>This document defines the SRv6 Network Programming concept and
      specifies the main segment routing Segment Routing behaviors to enable the creation of
      interoperable overlays with underlay optimization.</t>
            <t>The companion document <xref
      <t><xref
      target="I-D.filsfils-spring-srv6-net-pgm-illustration" />
      format="default"/> illustrates the concepts defined in this
      document.</t>
      <t>Familiarity with the <xref target="RFC8754">Segment target="RFC8754" format="default">Segment
      Routing Header</xref> is expected.</t>
    </section>
    <section title="Terminology"> numbered="true" toc="default">
      <name>Terminology</name>
      <t>The following terms used within this document are defined in <xref
      target="RFC8402" />: format="default"/>: Segment Routing, Routing (SR), SR Domain, Segment
      ID (SID), SRv6, SRv6 SID, SR Policy, Prefix-SID, and Adj-SID.</t>
      <t>The following terms used within this document are defined in <xref
      target="RFC8754" />: SRH, format="default"/>: Segment Routing Header (SRH), SR Source Node, Transit Node,
      source node, transit node, SR Segment Endpoint Node, Reduced SRH,
      Segments Left Left, and Last Entry.</t>

            <t>SL: The Segments Left field of the SRH</t>
            <t>FIB: Forwarding

<t>The following terms are used in this document as defined below:</t>

<dl>

<dt>FIB:
</dt>
<dd>Forwarding Information Base. A FIB lookup is a lookup in the forwarding table.</t>
            <t>SA: Source Address</t>
            <t>DA: Destination Address</t>

            <t>SRv6 table.
</dd>

<dt>SA:
</dt>
<dd>Source Address
</dd>

<dt>DA:
</dt>
<dd>Destination Address
</dd>

<dt>L3:
</dt>
<dd>Layer 3
</dd>

<dt>L2:
</dt>
<dd>Layer 2
</dd>

<dt>MAC:
</dt>
<dd>Media Access Control
</dd>

<dt>EVPN:
</dt>
<dd>Ethernet VPN
</dd>

<dt>ESI:
</dt>
<dd>Ethernet Segment Identifier
</dd>

<dt>Per-CE VPN label:
</dt>
<dd>A single label for each attachment circuit that is shared by all routes
with the same "outgoing attachment circuit" (<xref target="RFC4364"
format="default" sectionFormat="of" section="4.3.2"/>)
</dd>

<dt>Per-VRF VPN label:
</dt>

<dd>A single label for the entire VPN Routing and Forwarding (VRF) table that is
shared by all routes from that VRF (<xref target="RFC4364" format="default"
sectionFormat="of" section="4.3.2"/>)
</dd>

<dt>SL:
</dt>
<dd>The Segments Left field of the SRH
</dd>

<dt>SRv6 SID function: The
</dt>
<dd>The function part of the SID is an opaque identification of a local
behavior bound to the SID. It is formally defined in <xref target="sid_format" />
format="default"/> of this document.</t>

            <t>SRv6 Segment document.
</dd>

<dt>SRv6 Endpoint behavior: A
</dt>
<dd><t>A packet processing behavior executed at an SRv6 Segment Endpoint
Node. <xref target="behaviors" /> format="default"/> of this document defines
SRv6 Segment Endpoint behaviors related to traffic-engineering and overlay use-cases.
use cases. Other behaviors (e.g. (e.g., service programming) are outside the scope of
this document.</t> document.
</t>

</dd>

</dl>

<t>An SR Policy is resolved to a SID list. A SID list is represented as
&lt;S1, S2, S3&gt; where S1 is the first SID to visit, S2 is the second SID to visit
visit, and S3 is the last SID to visit along the SR path.</t>
  <t>(SA,DA) (S3, S2, S1; SL) represents an IPv6 packet with:<list style="format - ">
                <t>Source with:</t>

      <ul spacing="normal"><li>Source Address is SA, (SA), Destination Address is DA, (DA),
      and next-header is SRH.</t>
                <t>SRH next header (SRH).</li> <li><t>SRH with SID list &lt;S1, S2, S3&gt;
      with Segments Left = SL.</t>

<t>Note the difference between the
      &lt;&gt; and () symbols: &lt;S1, S2, S3&gt; represents a SID list where
      S1 is the first SID and S3 is the last SID to traverse. (S3, S2, S1; SL)
      represents the same SID list but encoded in the SRH format where the
      rightmost SID in the SRH is the first SID and the leftmost SID in the
      SRH is the last SID. When referring to an SR policy Policy in a high-level use-case,
      use case, it is simpler to use the &lt;S1, S2, S3&gt; notation. When
      referring to an illustration of the detailed packet behavior, the (S3,
      S2, S1; SL) notation is more convenient.</t>
                <t>The convenient.</t></li>

        <li>The payload of the packet is omitted.</t>
            </list></t>

            <t>Per-VRF VPN label: a single label for the entire VRF that is shared by all routes from that VRF (<xref target="RFC4364"/> Section 4.3.2)</t>

            <t>Per-CE VPN label: a single label for each attachment circuit that is shared by all routes with the same "outgoing attachment circuit" (<xref target="RFC4364"/> Section 4.3.2)</t> omitted.</li>
      </ul>

      <section title="Requirements Language">
                <t>The numbered="true" toc="default">
        <name>Requirements Language</name>

        <t>
    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 BCP&nbsp;14 <xref target="RFC2119" /> target="RFC2119"/>
    <xref target="RFC8174"/> when, and only when, they appear in all capitals,
    as shown here.</t> here.
        </t>

      </section>
    </section>
    <section title="SRv6 SID">
            <t>RFC8402 numbered="true" toc="default">
      <name>SRv6 SID</name>
      <t><xref target="RFC8402"/> defines an SRv6 Segment Identifier as an IPv6 address
      explicitly associated with the segment.</t>
      <t>When an SRv6 SID is in the Destination Address field of an IPv6
      header of a packet, it is routed through Transit Nodes transit nodes in an IPv6
      network as an IPv6 address.</t>
      <t>Its processing is defined in <xref target="RFC8754" /> section 4.3
      format="default" sectionFormat="of" section="4.3"/> and reproduced here as a reminder. <list style="empty"> reminder: </t>

<blockquote>
        <t>Without constraining the details of an implementation, the SR
        segment endpoint node creates Forwarding Information Base (FIB)
        entries for its local SIDs.</t>

          <t>When an SRv6-capable node receives an IPv6 packet, it performs a
          longest-prefix-match lookup on the packet's destination address.
          This lookup can return any of the following: <list style="format * ">

                    <t>A </t>

          <ul spacing="normal"><li>A FIB entry that represents a locally instantiated SRv6 SID</t>
                    <t>A SID</li>
            <li>A FIB entry that represents a local interface, not locally instantiated as an SRv6 SID</t>
                    <t>A SID</li>
            <li>A FIB entry that represents a nonlocal route</t>
                    <t>No Match</t>
                </list></t>
            </list></t> route</li>
            <li>No Match</li>
          </ul></blockquote>

      <t><xref target="behaviors" /> format="default"/> of this document defines
      a new set of SRv6 SID behaviors in addition to that defined in <xref
      target="RFC8754" /> Section 4.3.1.</t>

            <section title="SID Format" anchor="sid_format"> format="default" sectionFormat="of" section="4.3.1"/>.</t>
      <section anchor="sid_format" numbered="true" toc="default">
        <name>SID Format</name>

        <t>This document defines an SRv6 SID as consisting of LOC:FUNCT:ARG,
        where a locator (LOC) is encoded in the L most significant bits of the
        SID, followed by F bits of function (FUNCT) and A bits of arguments
        (ARG).  L, the locator length, is flexible, and an operator is free to
        use the locator length of their choice. F and A may be any value as
        long as L+F+A &lt;= 128. When L+F+A is less than 128 128, then the
        remaining bits of the SID MUST <bcp14>MUST</bcp14> be zero.</t>
        <t>A locator may be represented as B:N where B is the SRv6 SID block
        (IPv6 prefix allocated for SRv6 SIDs by the operator) and N is the
        identifier of the parent node instantiating the SID.</t>
        <t>When the LOC part of the SRv6 SIDs is routable, it leads to the node
        node, which instantiates the SID.</t>
        <t>The FUNCT is an opaque identification of a local behavior bound to the SID.</t>
        <t>The term &quot;function&quot; "function" refers to the bit-string bit string in the SRv6 SID. The
        term &quot;behavior&quot; "behavior" identifies the behavior bound to the SID. Some
        behaviors are defined in Section 4 <xref target="behaviors"/> of this
        document.</t>
        <t>An SRv6 Segment Endpoint Behavior behavior may require additional
        information for its processing (e.g. (e.g., related to the flow or
        service). This information may be encoded in the ARG bits of the
        SID.</t>

        <t>In such a case, the semantics and format of the ARG bits are
        defined as part of the SRv6 endpoint Endpoint behavior specification.</t>
        <t>The ARG value of a routed SID SHOULD <bcp14>SHOULD</bcp14> remain constant among packets in a given flow.  Varying ARG values among packets in a flow may result in different ECMP hashing and cause re-ordering.</t> reordering.</t>
      </section>

      <section title="SID numbered="true" toc="default">
        <name>SID Allocation within an SR domain"> Domain</name>
        <t>Locators are assigned consistent with IPv6 infrastructure allocation.  For example, a network operator may:
                    <list style="symbols">
                        <t>Assign
        </t>
        <ul spacing="normal">
          <li>Assign block B::/48 to the SR domain</t>
                        <t>Assign domain</li>
          <li>Assign a unique B:N::/64 block to each SRv6-enabled node in the domain</t>
                    </list>
                </t> domain</li>
        </ul>

        <t>As an example, one mobile service provider has commercially
        deployed SRv6 across more than 1000 commercial routers and 1800
        whitebox routers. All these devices are enabled for SRv6 and advertise
        SRv6 SIDs. The provider historically deployed IPv6 and assigned
        infrastructure addresses from ULA the Unique Local Address (ULA) space <xref
        target="RFC4193" />. format="default"/>. They specifically allocated three
        /48 prefixes (Country X, Country Y, Country Z) to support their SRv6
        infrastructure. From those /48 prefixes prefixes, each router was assigned a /64
        prefix from which all SIDs of that router are allocated.</t>
        <t>In another example, a large mobile and fixed-line service provider
        has commercially deployed SRv6 in their country-wide network. This
        provider is assigned a /20 prefix by an RIR (Regional a Regional Internet Registry).
        Registry (RIR). They sub-allocated a few /48 prefixes to their
        infrastructure to deploy SRv6. Each router is assigned a /64 prefix
        from which all SIDs of that router are allocated.</t>
        <t>IPv6 address consumption in both these examples is minimal,
        representing less than one billionth and one millionth of the
        available address space, respectively.</t>

        <t>A service provider receiving the current minimum allocation of a
        /32 prefix from an RIR may assign a /48 prefix to their infrastructure
        deploying SRv6, SRv6 and subsequently allocate /64 prefixes for SIDs at
        each SRv6 node. The /48 assignment is one sixty-five thousandth
        (1/2^16) of the usable IPv6 address space available for assignment by
        the provider.</t>
        <t>When an operator instantiates a SID at a node, they specify a SID
        value B:N:FUNCT and the behavior bound to the SID using one of the
        SRv6 Endpoint Behavior codepoint codepoints of the registry defined in this
        document (see <xref target="endpoint_cp_types" />).</t>
        format="default"/>).</t>
        <t>The node advertises the SID, B:N:FUNCT, in the control-plane control plane (see
        <xref target="cp" />) format="default"/>) together with the SRv6 Endpoint
        Behavior codepoint identifying the behavior of the SID.</t>
        <t>An SR Source Node source node cannot infer the behavior by examination of the
        FUNCT value of a SID.</t>
        <t>Therefore, the SRv6 Endpoint Behavior codepoint is advertised along
        with the SID in the control plane.</t>
        <t>An SR Source Node source node uses the SRv6 Endpoint Behavior codepoint to map
        the received SID (B:N:FUNCT) to a behavior.</t>
        <t>An SR Source Node source node selects a desired behavior at an advertising node
        by selecting the SID (B:N:FUNCT) advertised with the desired
        behavior.</t>
        <t>As an example, a example:
        </t>
        <ul spacing="normal">
          <li>A network operator may:
                    <list style="symbols">
                        <t>Assign may assign an SRv6 SID block
          2001:db8:bbbb::/48 from their in-house operation block for their
          SRv6 infrastructure</t>
                        <t>Assign infrastructure.</li>
          <li>A network operator may assign an SRv6 Locator 2001:db8:bbbb:3::/64 to one particular
          router, for example Router 3, in their SR Domain</t> Domain.</li>
          <li>

            <t>At Router 3, within the locator 2001:db8:bbbb:3::/64, the
            network operator or the router performs dynamic assignment for:
                            <list>
            </t>

            <ul spacing="normal">
              <li>
                <t>Function 0x0100 associated with the behavior End.X
                (Endpoint with L3 cross-connect) between router 3 and its
                connected neighbor router, for example router (e.g., Router 4. 4). This function
                is encoded as a 16-bit value and has no arguments (F=16, A=0).<vspace />
                A=0).</t>
                <t>
                                This SID is advertised in the control plane as
                                2001:db8:bbbb:3:100:: with an SRv6 Endpoint
                                Behavior codepoint value of 5.</t>
              </li>
              <li>
                <t>Function 0x0101 associated with the behavior End.X
                (Endpoint with L3 cross-connect) between router 3 and its
                connected neighbor router, for example router (e.g., Router 2. 2). This function is
                encoded as a 16-bit value and has no arguments (F=16, A=0).<vspace /> A=0).</t>
                <t>
                                This SID is advertised in the control plane as
                                2001:db8:bbbb:3:101:: with an SRv6 Endpoint
                                Behavior codepoint value of 5.</t>
                            </list>
                        </t>
                    </list>
                </t>
              </li>
            </ul>
          </li>
        </ul>
        <t>These examples do not preclude any other IPv6 addressing allocation scheme.</t>
      </section>
      <section title="SID Reachability"> numbered="true" toc="default">
        <name>SID Reachability</name>
        <t>Most often, the node N would advertise IPv6 prefix(es) matching the
        LOC parts covering its SIDs or shorter-mask prefix. The distribution
        of these advertisements and calculation of their reachability are
        specific to the routing protocol and are outside of the scope of this
        document.</t>
        <t>An SRv6 SID is said to be routed if its SID belongs to an IPv6
        prefix advertised via a routing protocol. An SRv6 SID that does not
        fulfill this condition is non-routed.</t>
        <t>Let's provide a classic illustration:</t>
        <t>Node N is configured explicitly with two SIDs: 2001:db8:b:1:100:: and 2001:db8:b:2:101::.</t>
        <t>The network learns about a path to 2001:db8:b:1::/64 via the IGP and hence IGP;
        hence, a packet destined to 2001:db8:b:1:100:: would be routed up
        to N. The network does not learn about a path to 2001:db8:b:2::/64 via
        the IGP and hence IGP; hence, a packet destined to 2001:db8:b:2:101:: would not be
        routed up to N.</t>

        <t>A packet could be steered through a non-routed SID
        2001:db8:b:2:101:: by using a SID list
        &lt;...,2001:db8:b:1:100::,2001:db8:b:2:101::,...&gt; where the
        non-routed SID is preceded by a routed SID to the same node. A packet
        could also be steered to a node instantiating a non-routed SID by
        preceding it in the SID-list SID list with an Adjacency SID Adj-SID to that
        node. Routed and non-routed SRv6 SIDs are the SRv6 instantiation of
        global and local segments, respectively <xref target="RFC8402"/>.<vspace blankLines="25" /></t> target="RFC8402"
        format="default"/>.</t>
      </section>
    </section>

        <?rfc needLines="40" ?>
    <section title="SR anchor="behaviors" numbered="true" toc="default">
      <name>SR Endpoint Behaviors" anchor="behaviors">
            <t>Following Behaviors</name>
      <t>The following is a set of well-known behaviors that can be associated with a SID.</t>
                <figure>
                    <artwork><![CDATA[
End                Endpoint function
                   The

<table anchor="endpoint">
  <name>Endpoint Behaviors</name>

  <tbody>
    <tr>
      <td>End</td>
      <td><t>Endpoint</t><t>The SRv6 instantiation of a Prefix SID [RFC8402]
End.X              Endpoint Prefix-SID <xref target="RFC8402"/></t></td>
    </tr>
    <tr>
      <td>End.X</td>
      <td><t>Endpoint with Layer-3 cross-connect
                   The L3 cross-connect</t>
      <t>The SRv6 instantiation of an Adj SID [RFC8402]
End.T              Endpoint Adj-SID <xref target="RFC8402"/>
      </t></td>

    </tr>
    <tr>
      <td>End.T</td>
      <td>Endpoint with specific IPv6 table lookup
End.DX6            Endpoint lookup</td>
    </tr>
    <tr>
      <td>End.DX6</td>
      <td><t>Endpoint with decapsulation and IPv6 cross-connect
                   e.g. cross-connect</t>
<t>e.g., IPv6-L3VPN (equivalent to per-CE VPN label)
End.DX4            Endpoint
</t>
</td>
    </tr>
    <tr>
      <td>End.DX4</td>
      <td><t>Endpoint with decaps decapsulation and IPv4 cross-connect
                   e.g. cross-connect</t>
<t>e.g., IPv4-L3VPN (equivalent to per-CE VPN label)
End.DT6            Endpoint
</t>
</td>
    </tr>
    <tr>
      <td>End.DT6</td>
      <td><t>Endpoint with decapsulation and specific IPv6 table lookup
                   e.g.
    </t>
    <t>e.g., IPv6-L3VPN (equivalent to per-VRF VPN label)
End.DT4            Endpoint
    </t>
      </td>
    </tr>
    <tr>
      <td>End.DT4</td>
      <td><t>Endpoint with decapsulation and specific IPv4 table lookup
                   e.g. lookup</t>
<t>e.g., IPv4-L3VPN (equivalent to per-VRF VPN label)
End.DT46           Endpoint
</t>
</td>
    </tr>
    <tr>
      <td>End.DT46</td>
      <td><t>Endpoint with decapsulation and specific IP table lookup
                   e.g. lookup</t>
      <t>e.g., IP-L3VPN (equivalent to per-VRF VPN label)
End.DX2            Endpoint
      </t>
      </td>
    </tr>
    <tr>
      <td>End.DX2</td>
      <td>
	<t>Endpoint with decapsulation and L2 cross-connect
                   e.g.
	</t>
	<t>e.g., L2VPN use-case
End.DX2V           Endpoint use case
	</t>
      </td>
    </tr>
    <tr>
      <td>End.DX2V</td>
      <td>
	<t>Endpoint with decaps decapsulation and VLAN L2 table lookup
                   e.g.
	</t>
      <t>e.g., EVPN Flexible cross-connect use-case
End.DT2U           Endpoint Cross-connect use case
      </t>
</td>
    </tr>
    <tr>
      <td>End.DT2U</td>
      <td>
	<t>Endpoint with decaps decapsulation and unicast MAC L2 table lookup
                   e.g.
	</t>
	<t>e.g., EVPN Bridging unicast use-case
End.DT2M           Endpoint Unicast use case
	</t>
</td>
    </tr>
    <tr>
      <td>End.DT2M</td>
      <td><t>Endpoint with decapsulation and L2 table flooding
                   e.g. flooding</t>
      <t>e.g., EVPN Bridging BUM use-case Broadcast, Unknown Unicast, and Multicast (BUM) use case with ESI Ethernet Segment Identifier (ESI) filtering
End.B6.Encaps      Endpoint
      </t>
      </td>
    </tr>
    <tr>
      <td>End.B6.Encaps</td>
      <td><t>Endpoint bound to an SRv6 policy Policy with encapsulation
                   SRv6 encapsulation</t>
      <t>SRv6 instantiation of a Binding SID
End.B6.Encaps.Red  End.B6.Encaps
      </t>
      </td>
    </tr>
    <tr>
      <td>End.B6.Encaps.Red</td>

      <td>
	<t>End.B6.Encaps with reduced SRH
                   SRv6
	</t>
	<t>SRv6 instantiation of a Binding SID
End.BM             Endpoint
	</t>
      </td>
    </tr>
    <tr>
      <td>End.BM</td>
      <td>
	<t>Endpoint bound to an SR-MPLS Policy
                   SRv6
	</t>
	<t>SRv6 instantiation of an SR-MPLS Binding SID
                    ]]></artwork>
                </figure>
	</t>
</td>
    </tr>
  </tbody>
</table>

      <t>The list is not exhaustive. In practice, any behavior can be attached
      to a local SID: e.g. SID; for example, a node N can bind a SID to a local VM Virtual
      Machine (VM) or container which that can apply any complex processing on the
      packet, provided there is a behavior an SRv6 Endpoint Behavior codepoint allocated
      for the processing.</t>
      <t>When an SRv6-capable node (N) receives an IPv6 packet whose
      destination address matches a FIB entry that represents a locally
      instantiated SRv6 SID (S), the IPv6 header chain is processed as defined
      in Section 4 of <xref target="RFC8200" />. sectionFormat="of" section="4" format="default"/>. For SRv6 SIDs
      associated with an Endpoint Behavior behavior defined in this document, the SRH
      and Upper-layer Header Upper-Layer header are processed as defined in the following
      subsections.</t>
      <t>The pseudocode describing these behaviors details local processing at
      a node. An implementation of the pseudocode is compliant as long as the
      externally observable wire protocol is as described by the
      pseudocode.</t>
      <t><xref target="BehFlavors" /> format="default"/> defines flavors of some of these behaviors.</t>
      <t><xref target="iana_registry" /> format="default"/> of this document
      defines the IANA Registry registry used to maintain all these behaviors as well
      as future ones defined in other documents.</t>

            <?rfc needLines="40" ?>

      <section title="End: Endpoint"> numbered="true" toc="default">
        <name>End: Endpoint</name>
        <t>The Endpoint behavior ("End" for short) is the most basic
        behavior. It is the instantiation of a Prefix-SID <xref
        target="RFC8402" />.</t>

                <t><vspace blankLines="2" />When format="default"/>.</t>

        <t>When N receives a packet whose IPv6 DA is S and S is a local End SID, N does:</t>

                <figure>
                    <artwork><![CDATA[ does the following:</t>
<sourcecode type="pseudocode">
S01. When an SRH is processed {
S02.   If (Segments Left == 0) {
S03.      Stop processing the SRH, and proceed to process the next
             header in the packet, whose type is identified by
             the Next Header field in the routing header.
S04.   }
S05.   If (IPv6 Hop Limit <= &lt;= 1) {
S06.      Send an ICMP Time Exceeded message to the Source Address, Address
             with Code 0 (Hop limit exceeded in transit),
             interrupt packet processing processing, and discard the packet.
S07.   }
S08.   max_LE = (Hdr Ext Len / 2) - 1
S09.   If ((Last Entry > max_LE) or (Segments Left > Last Entry+1)) {
S10.      Send an ICMP Parameter Problem to the Source Address, Address
             with Code 0 (Erroneous header field encountered), encountered)
             and Pointer set to the Segments Left field,
             interrupt packet processing processing, and discard the packet.

S11.   }
S12.   Decrement IPv6 Hop Limit by 1
S13.   Decrement Segments Left by 1
S14.   Update IPv6 DA with Segment List[Segments Left]
S15.   Submit the packet to the egress IPv6 FIB lookup and for
          transmission to the new destination
S16. }
                    ]]></artwork>
                </figure>
                <t>Notes:<vspace blankLines="0" />
                The
</sourcecode>
<aside>
<t>Note:</t>
<t>The End behavior operates on the same FIB table (i.e. (i.e.,
identified by VRF or L3 relay id) ID) associated to the packet. Hence Hence, the FIB
lookup on line S15 is done in the same FIB table as the ingress interface.</t> interface.
</t>
</aside>

        <section title="Upper-Layer Header" anchor="upper"> anchor="upper" numbered="true" toc="default">
          <name>Upper-Layer Header</name>
          <t>When processing the Upper-layer Header Upper-Layer header of a packet matching a FIB
          entry locally instantiated as an End SID, N does:</t>
                    <figure>
                        <artwork><![CDATA[ does the following:</t>
<sourcecode type="pseudocode">
S01. If (Upper-Layer Header header type is allowed by local configuration) {
S02.   Proceed to process the Upper-layer Header Upper-Layer header
S03. } Else {
S04.   Send an ICMP Parameter Problem to the Source Address, Address
          with Code 4 (SR Upper-layer Header Error), Error)
          and Pointer set to the offset of the Upper-layer Header,
          Interrupt Upper-Layer header,
          interrupt packet processing processing, and discard the packet.
S05  }
                    ]]></artwork>
                    </figure>
</sourcecode>
          <t>Allowing the processing of specific Upper-Layer Headers header types is
          useful for OAM. Operations, Administration, and Maintenance (OAM). As an
          example, an operator might permit pinging of SIDs. To do this this, they
          may enable local configuration to allow Upper-layer Header Upper-Layer header type 58
          (ICMPv6).</t>
          <t>It is RECOMMENDED <bcp14>RECOMMENDED</bcp14> that an implementation of local
          configuration only allows Upper-layer Header Upper-Layer header processing of types
          that do not result in the packet being forwarded (e.g. (e.g., ICMPv6).</t>
        </section>
      </section>

            <?rfc needLines="20" ?>
            <section title="End.X: Layer-3 Cross-Connect">
      <section numbered="true" toc="default">
        <name>End.X: L3 Cross-Connect</name>
        <t>The "Endpoint with cross-connect to an array of layer-3 adjacencies" L3 cross-connect" behavior (End.X ("End.X" for short) is a variant of the End behavior.</t>
        <t>It is the SRv6 instantiation of an Adjacency-SID Adj-SID <xref target="RFC8402" /> format="default"/>, and its main use is for traffic-engineering policies.</t>
        <t>Any SID instance of this behavior is associated with a set, J, of
        one or more Layer-3 L3 adjacencies.</t>

                <t><vspace blankLines="2" />When
        <t>When N receives a packet destined to S and S is a local End.X SID, the line S15 from the End processing is replaced by the following:</t>

                <figure> <artwork><![CDATA[
<sourcecode type="pseudocode">
S15.   Submit the packet to the IPv6 module for transmission
          to the new destination via a member of J
                    ]]></artwork>
                </figure>

                <t>Notes:<vspace blankLines="0" />
</sourcecode>

<aside>
<t>Note:</t>
<t> S15. If the set J contains several L3 adjacencies, then one element
of the set is selected based on a hash of the packet's header (see <xref
target="OpsFlowLabel" />).</t>

                <t><vspace blankLines="2" />If format="default"/>).</t>
</aside>
        <t>If a node N has 30 outgoing interfaces to 30 neighbors, usually the
        operator would explicitly instantiate 30 End.X SIDs at N: one per layer-3
        L3 adjacency to a neighbor.  Potentially, more End.X could be
        explicitly defined (groups of layer-3 L3 adjacencies to the same neighbor
        or to different neighbors).</t>

        <t>Note that if N has an outgoing interface bundle I to a neighbor Q
        made of 10 member links, N might allocate up to 11 End.X local SIDs:
        one for the bundle itself and then up to one for each Layer-2 L2 member
        link. The flows steered using the End.X SID corresponding to the
        bundle itself get load balanced load-balanced across the member links via hashing
        while the flows steered using the End.X SID corresponding to a member
        link get steered over that specific member link alone.</t>

                <t><vspace blankLines="2" />When
        <t>When the End.X behavior is associated with a BGP Next-Hop, it is
        the SRv6 instantiation of the BGP Peering Segments peering segments <xref
        target="RFC8402" />.<vspace blankLines="2" /></t> format="default"/>.</t>
        <t>When processing the Upper-layer Header Upper-Layer header of a packet matching a FIB
        entry locally instantiated as an End.X SID, process the packet as per
        <xref target="upper"/>.</t> target="upper" format="default"/>.</t>

      </section>

            <?rfc needLines="20" ?>
      <section title="End.T: numbered="true" toc="default">
        <name>End.T: Specific IPv6 Table Lookup"> Lookup</name>
        <t>The "Endpoint with specific IPv6 table lookup" behavior (End.T ("End.T" for
        short) is a variant of the End behavior.</t>
        <t>The End.T behavior is used for multi-table operation in the
        core. For this reason, an instance of the End.T behavior is associated
        with an IPv6 FIB table T.</t>

                <t><vspace blankLines="2" />When
        <t>When N receives a packet destined to S and S is a local End.T SID,
        the line S15 from the End processing is replaced by the following:</t>

                <figure> <artwork><![CDATA[
<sourcecode type="pseudocode">
S15.1.   Set the packet's associated FIB table to T
S15.2.   Submit the packet to the egress IPv6 FIB lookup and for
           transmission to the new destination
                ]]></artwork> </figure>
</sourcecode>
        <t>When processing the Upper-layer Header Upper-Layer header of a packet matching a FIB entry locally instantiated as an End.T SID, process the packet as per <xref target="upper"/>.</t> target="upper" format="default"/>.</t>
      </section>
      <section title="End.DX6: numbered="true" toc="default">
        <name>End.DX6: Decapsulation and IPv6 Cross-Connect"> Cross-Connect</name>
        <t>The "Endpoint with decapsulation and cross-connect to an array of IPv6 adjacencies" cross-connect" behavior (End.DX6 ("End.DX6" for short) is a variant of the End.X behavior.</t>
        <t>One of the applications of the End.DX6 behavior is the L3VPNv6 use-case use case where a FIB lookup in a specific tenant table at the egress Provider Edge (PE) is not required. This is equivalent to the per-CE VPN label in MPLS <xref target="RFC4364" />.</t> format="default"/>.</t>
        <t>The End.DX6 SID MUST <bcp14>MUST</bcp14> be the last segment in a an SR Policy, and it is associated with one or more L3 IPv6 adjacencies J.</t>

                <t><vspace blankLines="2" />When
        <t>When N receives a packet destined to S and S is a local End.DX6 SID, N does:</t>

                <figure><artwork><![CDATA[ does the following:</t>
<sourcecode type="pseudocode">
S01. When an SRH is processed {
S02.   If (Segments Left != 0) {
S03.      Send an ICMP Parameter Problem to the Source Address, Address
             with Code 0 (Erroneous header field encountered), encountered)
             and Pointer set to the Segments Left field,
             interrupt packet processing processing, and discard the packet.
S04.   }
S05.   Proceed to process the next header in the packet
S06. }
                ]]></artwork></figure>

                <t><vspace blankLines="2" />When
</sourcecode>
        <t>When processing the Upper-layer Upper-Layer header of a packet matching a FIB entry locally instantiated as an End.DX6 SID, N does:</t>

                <figure><artwork><![CDATA[ does the following:</t>
<sourcecode type="pseudocode">
S01. If (Upper-Layer Header header type == 41(IPv6) ) {
S02.    Remove the outer IPv6 Header header with all its extension headers
S03.    Forward the exposed IPv6 packet to the L3 adjacency J
S04. } Else {
S05.    Process as per Section 4.1.1
S06. }
                ]]></artwork></figure>

                <t>Notes:<vspace blankLines="0" />
</sourcecode>

<aside>
 <t>Note:</t>
<t>
                S01. 41 "41" refers to IPv6 encapsulation "IPv6 encapsulation" as defined by in the IANA allocation for
                "Assigned Internet Protocol Numbers.<vspace blankLines="0" /> Numbers" registry.
</t>

<t>
S03. If the End.DX6 SID is bound to an array of L3 adjacencies, then one entry
of the array is selected based on the hash of the packet's header (see <xref
target="OpsFlowLabel" />).</t> format="default"/>).</t>
</aside>
      </section>
      <section title="End.DX4: numbered="true" toc="default">
        <name>End.DX4: Decapsulation and IPv4 Cross-Connect"> Cross-Connect</name>
        <t>The "Endpoint with decapsulation and cross-connect to an array of IPv4 adjacencies" cross-connect" behavior (End.DX4
        ("End.DX4" for short) is a variant of the End.X behavior.</t>
        <t>One of the applications of the End.DX4 behavior is the L3VPNv4 use-case use
        case where a FIB lookup in a specific tenant table at the egress PE is
        not required. This is equivalent to the per-CE VPN label in MPLS <xref
        target="RFC4364" />.</t> format="default"/>.</t>
        <t>The End.DX4 SID MUST <bcp14>MUST</bcp14> be the last segment in a an SR
        Policy, and it is associated with one or more L3 IPv4 adjacencies
        J.</t>
                <t><vspace blankLines="2" />When
        <t>When N receives a packet destined to S and S is a local End.DX4
        SID, N does:</t>

                <figure><artwork><![CDATA[ does the following:</t>
<sourcecode type="pseudocode">
S01. When an SRH is processed {
S02.   If (Segments Left != 0) {
S03.      Send an ICMP Parameter Problem to the Source Address, Address
             with Code 0 (Erroneous header field encountered), encountered)
             and Pointer set to the Segments Left field,
             interrupt packet processing processing, and discard the packet.
S04.   }
S05.   Proceed to process the next header in the packet
S06. }
                ]]></artwork></figure>

                <t><vspace blankLines="2" />When
</sourcecode>
        <t>When processing the Upper-layer Upper-Layer header of a packet matching a FIB entry locally instantiated as an End.DX4 SID, N does:</t>
                <figure><artwork><![CDATA[ does the following:</t>
<sourcecode type="pseudocode">
S01. If (Upper-Layer Header header type == 4(IPv4) ) {
S02.    Remove the outer IPv6 Header header with all its extension headers
S03.    Forward the exposed IPv4 packet to the L3 adjacency J
S04. } Else {
S05.    Process as per Section 4.1.1
S06. }
                ]]></artwork></figure>
                <t>Notes:<vspace blankLines="0" />
</sourcecode>
<aside>
        <t>Note:</t>
<t>
                S01. 4 "4" refers to IPv4 encapsulation "IPv4 encapsulation" as defined by in the IANA allocation for
                "Assigned Internet Protocol Numbers<vspace blankLines="0" /> Numbers" registry.
</t>
<t>

S03. If the End.DX4 SID is bound to an array of L3 adjacencies, then one entry
of the array is selected based on the hash of the packet's header (see <xref
target="OpsFlowLabel" />).</t> format="default"/>).</t>
</aside>
      </section>
      <section title="End.DT6: numbered="true" toc="default">
        <name>End.DT6: Decapsulation and Specific IPv6 Table Lookup"> Lookup</name>
        <t>The "Endpoint with decapsulation and specific IPv6 table lookup"
        behavior (End.DT6 ("End.DT6" for short) is a variant of the End.T behavior.</t>
        <t>One of the applications of the End.DT6 behavior is the
        L3VPNv6 use-case use case where a FIB
        lookup in a specific tenant table at the egress PE is required. This
        is equivalent to the per-VRF VPN label in MPLS <xref target="RFC4364" />.</t>
        format="default"/>.</t>
        <t>Note that an End.DT6 may be defined for the main IPv6 table table, in
        which case an End.DT6 supports the equivalent of an IPv6inIPv6 IPv6-in-IPv6
        decapsulation (without VPN/tenant implication).</t>
        <t>The End.DT6 SID MUST <bcp14>MUST</bcp14> be the last segment in a an SR
        Policy, and a SID instance is associated with an IPv6 FIB table T.</t>

                <t><vspace blankLines="2" />When
        <t>When N receives a packet destined to S and S is a local End.DT6 SID, N does:</t>
                <figure><artwork><![CDATA[ does the following:</t>
<sourcecode type="pseudocode">
S01. When an SRH is processed {
S02.   If (Segments Left != 0) {
S03.      Send an ICMP Parameter Problem to the Source Address, Address
             with Code 0 (Erroneous header field encountered), encountered)
             and Pointer set to the Segments Left field,
             interrupt packet processing processing, and discard the packet.
S04.   }
S05.   Proceed to process the next header in the packet
S06. }
                ]]></artwork></figure>

                <t><vspace blankLines="2" />When
</sourcecode>
        <t>When processing the Upper-layer Upper-Layer header of a packet matching a FIB entry locally instantiated as an End.DT6 SID, N does:</t>
                <figure><artwork><![CDATA[ does the following:</t>
<sourcecode type="pseudocode">
S01. If (Upper-Layer Header header type == 41(IPv6) ) {
S02.    Remove the outer IPv6 Header header with all its extension headers
S03.    Set the packet's associated FIB table to T
S04.    Submit the packet to the egress IPv6 FIB lookup and for
           transmission to the new destination
S05. } Else {
S06.    Process as per Section 4.1.1
S07. }
                ]]></artwork></figure>
</sourcecode>
      </section>
      <section title="End.DT4: numbered="true" toc="default">
        <name>End.DT4: Decapsulation and Specific IPv4 Table Lookup"> Lookup</name>
        <t>The "Endpoint with decapsulation and specific IPv4 table lookup" behavior (End.DT4 ("End.DT4" for short) is a variant of the End.T behavior.</t>
        <t>One of the applications of the End.DT4 behavior is the L3VPNv4 use-case use case where a FIB lookup in a specific tenant table at the egress PE is required. This is equivalent to the per-VRF VPN label in MPLS <xref target="RFC4364" />.</t> format="default"/>.</t>
        <t>Note that an End.DT4 may be defined for the main IPv4 table table, in which case an End.DT4 supports the equivalent of an IPv4inIPv6 IPv4-in-IPv6 decapsulation (without VPN/tenant implication).</t>
        <t>The End.DT4 SID MUST <bcp14>MUST</bcp14> be the last segment in a an SR Policy, and a SID instance is associated with an IPv4 FIB table T.</t>

                <t><vspace blankLines="2" />When
        <t>When N receives a packet destined to S and S is a local End.DT4 SID, N does:</t>
                <figure><artwork><![CDATA[ does the following:</t>
<sourcecode type="pseudocode">
S01. When an SRH is processed {
S02.   If (Segments Left != 0) {
S03.      Send an ICMP Parameter Problem to the Source Address, Address
             with Code 0 (Erroneous header field encountered), encountered)
             and Pointer set to the Segments Left field,
             interrupt packet processing processing, and discard the packet.
S04.   }
S05.   Proceed to process the next header in the packet
S06. }
                ]]></artwork></figure>

                <t><vspace blankLines="2" />When
</sourcecode>
        <t>When processing the Upper-layer Upper-Layer header of a packet matching a FIB entry locally instantiated as an End.DT4 SID, N does:</t>
                <figure><artwork><![CDATA[ does the following:</t>
<sourcecode type="pseudocode">
S01. If (Upper-Layer Header header type == 4(IPv4) ) {
S02.    Remove the outer IPv6 Header header with all its extension headers
S03.    Set the packet's associated FIB table to T
S04.    Submit the packet to the egress IPv4 FIB lookup and for
           transmission to the new destination
S05. } Else {
S06.    Process as per Section 4.1.1
S07. }
                ]]></artwork></figure>
</sourcecode>
      </section>
      <section title="End.DT46: numbered="true" toc="default">
        <name>End.DT46: Decapsulation and Specific IP Table Lookup"> Lookup</name>
        <t>The "Endpoint with decapsulation and specific IP table lookup"
        behavior (End.DT46 ("End.DT46" for short) is a variant of the End.DT4 and End.DT6
        behavior.</t>
        <t>One of the applications of the End.DT46 behavior is the L3VPN use-case
        use case where a FIB lookup in a specific IP tenant table at the
        egress PE is required. This is equivalent to the single per-VRF VPN label
        (for IPv4 and IPv6) in MPLS<xref MPLS <xref target="RFC4364" />.</t>
        format="default"/>.</t>
        <t>Note that an End.DT46 may be defined for the main IP table table, in which
        case an End.DT46 supports the equivalent of an IPinIPv6 decapsulation(without IP-in-IPv6
        decapsulation (without VPN/tenant implication).</t>
        <t>The End.DT46 SID MUST <bcp14>MUST</bcp14> be the last segment in a an SR
        Policy, and a SID instance is associated with an IPv4 FIB table T4 and
        an IPv6 FIB table T6.</t>
                <t><vspace blankLines="2" />When
        <t>When N receives a packet destined to S and S is a local End.DT46
        SID, N does:</t>
                <figure><artwork><![CDATA[ does the following:</t>
<sourcecode type="pseudocode">
S01. When an SRH is processed {
S02.   If (Segments Left != 0) {
S03.      Send an ICMP Parameter Problem to the Source Address, Address
             with Code 0 (Erroneous header field encountered), encountered)
             and Pointer set to the Segments Left field,
             interrupt packet processing processing, and discard the packet.
S04.   }
S05.   Proceed to process the next header in the packet
S06. }
                ]]></artwork></figure>

                <t><vspace blankLines="2" />When
</sourcecode>
        <t>When processing the Upper-layer Upper-Layer header of a packet matching a FIB entry locally instantiated as an End.DT46 SID, N does:</t>
                <figure><artwork><![CDATA[ does the following:</t>
<sourcecode type="pseudocode">
S01. If (Upper-layer Header (Upper-Layer header type == 4(IPv4) ) {
S02.    Remove the outer IPv6 Header header with all its extension headers
S03.    Set the packet's associated FIB table to T4
S04.    Submit the packet to the egress IPv4 FIB lookup and for
           transmission to the new destination
S05. } Else if (Upper-layer Header (Upper-Layer header type == 41(IPv6) ) {
S06.    Remove the outer IPv6 Header header with all its extension headers
S07.    Set the packet's associated FIB table to T6
S08.    Submit the packet to the egress IPv6 FIB lookup and for
           transmission to the new destination
S09. } Else {
S10.    Process as per Section 4.1.1
S11. }
                ]]></artwork></figure>
</sourcecode>
      </section>
      <section title="End.DX2: numbered="true" toc="default">
        <name>End.DX2: Decapsulation and L2 Cross-Connect"> Cross-Connect</name>
        <t>The "Endpoint with decapsulation and Layer-2 cross-connect to an outgoing L2 interface (OIF)" (End.DX2 cross-connect" behavior
        ("End.DX2" for short) is a variant of the endpoint Endpoint behavior.</t>
        <t>One of the applications of the End.DX2 behavior is the L2VPN <xref target="RFC4664" /> format="default"/> / EVPN VPWS Virtual Private Wire Service (VPWS) <xref target="RFC7432" /> format="default"/> <xref target="RFC8214" /> use-case.</t> format="default"/> use case.</t>
        <t>The End.DX2 SID MUST <bcp14>MUST</bcp14> be the last segment in a an SR Policy, and it is associated with one outgoing interface I.</t>

                <t><vspace blankLines="2" />When
        <t>When N receives a packet destined to S and S is a local End.DX2 SID, N does:</t>

                <figure><artwork><![CDATA[ does the following:</t>
<sourcecode type="pseudocode">
S01. When an SRH is processed {
S02.   If (Segments Left != 0) {
S03.      Send an ICMP Parameter Problem to the Source Address, Address
             with Code 0 (Erroneous header field encountered), encountered)
             and Pointer set to the Segments Left field,
             interrupt packet processing processing, and discard the packet.
S04.   }
S05.   Proceed to process the next header in the packet
S06. }
                ]]></artwork></figure>

                <t><vspace blankLines="2" />When
</sourcecode>
        <t>When processing the Upper-layer Upper-Layer header of a packet matching a FIB entry locally instantiated as an End.DX2 SID, N does:</t>

                <figure><artwork><![CDATA[ does the following:</t>
<sourcecode type="pseudocode">
S01. If (Upper-Layer Header header type == 143(Ethernet) ) {
S02.    Remove the outer IPv6 Header header with all its extension headers
S03.    Forward the Ethernet frame to the OIF I
S04. } Else {
S05.    Process as per Section 4.1.1
S06. }
                ]]></artwork></figure>
                <t>Notes:<vspace blankLines="0" />
                S01.
</sourcecode>

<aside>
        <t>Note:</t> <t>S01. IANA has allocated value "143" for "Ethernet"
        <xref target="IEEE.802.3_2018" format="default"/> in the "Assigned
        Internet Protocol number 143 to Ethernet <xref target="IEEE.802.3_2018"/> Numbers" registry (see <xref target="ianaethernet" />).<vspace blankLines="0" />
        format="default"/>). </t>
<t>
S03. An End.DX2 behavior could be customized to expect a specific IEEE header (e.g.
(e.g., VLAN tag) and rewrite the egress IEEE header before forwarding on the
outgoing interface.</t>

                <t><vspace blankLines="2" />Note
</aside>
        <t>Note that an End.DX2 SID may also be associated with a bundle of
        outgoing interfaces.</t>
      </section>
      <section title="End.DX2V: numbered="true" toc="default">
        <name>End.DX2V: Decapsulation and VLAN L2 Table Lookup"> Lookup</name>

        <t>The "Endpoint with decapsulation and specific VLAN L2 table lookup" behavior (End.DX2V
        ("End.DX2V" for short) is a variant of the End.DX2 behavior.</t>
        <t>One of the applications of the End.DX2V behavior is the EVPN
        Flexible cross-connect use-case. Cross-connect use case. The End.DX2V behavior is used to
        perform a lookup of the Ethernet frame VLANs in a particular L2
        table. Any SID instance of this behavior is associated with an L2 Table
        table T.</t>

                <t><vspace blankLines="2" />When
        <t>When N receives a packet whose IPv6 DA is S and S is a local
        End.DX2 SID, the processing is identical to the End.DX2 behavior
        except for the Upper-layer Upper-Layer header processing processing, which is modified as
        follows:</t>

                <figure><artwork><![CDATA[
<sourcecode type="pseudocode">
S03. Lookup Look up the exposed VLANs in L2 table T, and forward
        via the matched table entry.
                ]]></artwork></figure>
                <t>Notes:<vspace blankLines="0" />
</sourcecode>
<aside>
        <t>Note:</t>
<t> S03. An End.DX2V behavior could be customized to expect a specific VLAN
format and rewrite the egress VLAN header before forwarding on the outgoing
interface.</t>
</aside>
      </section>
      <section title="End.DT2U: numbered="true" toc="default">
        <name>End.DT2U: Decapsulation and Unicast MAC L2 Table Lookup"> Lookup</name>
        <t>The "Endpoint with decapsulation and specific unicast MAC L2 table lookup"
        behavior (End.DT2U ("End.DT2U" for short) is a variant of the End behavior.</t>
        <t>One of the applications of the End.DT2U behavior is the EVPN
        Bridging unicast Unicast <xref target="RFC7432" />. format="default"/>. Any SID
        instance of the End.DT2U behavior is associated with an L2 Table table
        T.</t>

                <t><vspace blankLines="2" />When
        <t>When N receives a packet whose IPv6 DA is S and S is a local
        End.DT2U SID, the processing is identical to the End.DX2 behavior
        except for the Upper-layer Upper-Layer header processing processing, which is as follows:</t>

                <figure><artwork><![CDATA[

<sourcecode type="pseudocode">
S01. If (Upper-Layer Header header type == 143(Ethernet) ) {
S02.    Remove the outer IPv6 Header header with all its extension headers
S03.    Learn the exposed MAC Source Address in L2 Table table T
S04.    Lookup    Look up the exposed MAC Destination Address in L2 Table table T
S05.    If (matched entry in T) {
S06.       Forward via the matched table T entry
S07.    } Else {
S08.       Forward via all L2 OIFs entries in table T
S09.    }
S10. } Else {
S11.    Process as per Section 4.1.1
S12. }
                ]]></artwork></figure>

                <t>Notes:<vspace blankLines="0" />
                S01.
</sourcecode>
<aside>
        <t>Note:</t> <t>S01. IANA has allocated value "143" for "Ethernet" in
        the "Assigned Internet Protocol number 143 to Ethernet Numbers" registry (see <xref
        target="ianaethernet" />).<vspace blankLines="0" /> format="default"/>).
 </t>
<t>
S03. In EVPN <xref target="RFC7432" />, format="default"/>, the learning of the
exposed MAC Source Address is done via the control plane. In L2VPN VPLS Virtual Private LAN Service (VPLS) <xref
target="RFC4761" /> format="default"/> <xref target="RFC4762" /> format="default"/>,
reachability is obtained by standard learning bridge functions in the data
plane.</t>
</aside>
      </section>

      <section title="End.DT2M: numbered="true" toc="default">
        <name>End.DT2M: Decapsulation and L2 Table Flooding"> Flooding</name>
        <t>The "Endpoint with decapsulation and specific L2 table flooding" behavior (End.DT2M
        ("End.DT2M" for short) is a variant of the End.DT2U behavior.</t>
        <t>Two of the applications of the End.DT2M behavior are the EVPN
        Bridging of broadcast, unknown Broadcast, Unknown Unicast, and multicast Multicast (BUM) traffic
        with Ethernet Segment Identifier (ESI) filtering <xref
        target="RFC7432" /> format="default"/> and the EVPN ETREE Ethernet-Tree
        (E-Tree) <xref target="RFC8317"/>use-cases.</t> target="RFC8317" format="default"/> use cases.</t>
        <t>Any SID instance of this behavior is associated with a an L2 table
        T. The behavior also takes an argument: "Arg.FE2". This argument
        provides a local mapping to ESI for split-horizon filtering of the
        received traffic to exclude a specific OIF (or set of OIFs) from L2
        table T flooding. The allocation of the argument values is local to
        the SR Segment Endpoint Node instantiating this behavior behavior, and the signaling of
        the argument to other nodes for the EVPN functionality occurs via the
        control plane.</t>

                <t><vspace blankLines="2" />When
        <t>When N receives a packet whose IPv6 DA is S and S is a local
        End.DT2M SID, the processing is identical to the End.DX2 behavior
        except for the Upper-layer Upper-Layer header processing processing, which is as follows:</t>

                <figure><artwork><![CDATA[

<sourcecode type="pseudocode">
S01. If (Upper-Layer Header header type == 143(Ethernet) ) {
S02.    Remove the outer IPv6 Header header with all its extension headers
S03.    Learn the exposed MAC Source Address in L2 Table table T
S04.    Forward via all L2OIFs L2 OIFs excluding those associated by with the
           identifier Arg.FE2
S05. } Else {
S06.    Process as per Section 4.1.1
S07. }
                ]]></artwork></figure>
                <t>Notes:<vspace blankLines="0" />
                S01.
</sourcecode>
<aside>
<t>Note:</t>

<t>S01. IANA has allocated value "143" for "Ethernet" in
        the "Assigned Internet Protocol number 143 to Ethernet Numbers" registry (see <xref
        target="ianaethernet" />).<vspace blankLines="0" /> format="default"/>).
</t>
<t>
S03. In EVPN <xref target="RFC7432" />, format="default"/>, the learning of the
exposed MAC Source Address is done via the control plane. In L2VPN VPLS <xref
target="RFC4761" /> format="default"/> <xref target="RFC4762" /> format="default"/>,
reachability is obtained by standard learning bridge functions in the data
plane.</t>
</aside>
      </section>
      <section title="End.B6.Encaps: numbered="true" toc="default">
        <name>End.B6.Encaps: Endpoint Bound to an SRv6 Policy w/ Encaps"> with Encapsulation</name>
        <t>This is a variation of the End behavior.</t>
        <t>One of its applications is to express scalable traffic-engineering policies across multiple domains. It is one of the SRv6 instantiations of a Binding SID <xref target="RFC8402" />.</t> format="default"/>.</t>
        <t>Any SID instance of this behavior is associated with an SR Policy B and a source address A.</t>

                <t><vspace blankLines="2" />When
        <t>When N receives a packet whose IPv6 DA is S and S is a local End.B6.Encaps SID, N does:</t>
                <figure><artwork><![CDATA[ does the following:</t>
<sourcecode type="pseudocode">
S01. When an SRH is processed {
S02.   If (Segments Left == 0) {
S03.      Stop processing the SRH, and proceed to process the next
             header in the packet, whose type is identified by
             the Next Header field in the routing header.
S04.   }
S05.   If (IPv6 Hop Limit <= &lt;= 1) {
S06.      Send an ICMP Time Exceeded message to the Source Address, Address
             with Code 0 (Hop limit exceeded in transit),
             interrupt packet processing processing, and discard the packet.
S07.   }
S08.   max_LE = (Hdr Ext Len / 2) - 1
S09.   If ((Last Entry > max_LE) or (Segments Left > (Last Last Entry+1)) {
S10.      Send an ICMP Parameter Problem to the Source Address, Address
             with Code 0 (Erroneous header field encountered), encountered)
             and Pointer set to the Segments Left field,
             interrupt packet processing processing, and discard the packet.
S11.   }
S12.   Decrement IPv6 Hop Limit by 1
S13.   Decrement Segments Left by 1
S14.   Update IPv6 DA with Segment List[Segments Left]
S15.   Push a new IPv6 header with its own SRH containing B
S16.   Set the outer IPv6 SA to A
S17.   Set the outer IPv6 DA to the first SID of B
S18.   Set the outer Payload Length, Traffic Class, Flow Label,
          Hop Limit Limit, and Next-Header Next Header fields
S19.   Submit the packet to the egress IPv6 FIB lookup and for
          transmission to the new destination
S20. }
                ]]></artwork></figure>

                <t>Notes:<vspace blankLines="0" />
</sourcecode>
<aside>
      <t>Note:</t>
<t>
                S15. The SRH MAY <bcp14>MAY</bcp14> be omitted when the SRv6 Policy B only contains one SID and there is no need to use any flag, tag tag, or TLV.<vspace blankLines="0" /> TLV.
</t>

<t>
S18. The Payload Length, Traffic Class, Hop Limit Limit, and Next-Header Next Header fields are set as per <xref target="RFC2473" />. format="default"/>. The Flow Label is computed as per <xref target="RFC6437" />.</t>

                <t><vspace blankLines="2" />When format="default"/>.</t>
</aside>
        <t>When processing the Upper-layer Upper-Layer header of a packet matching a FIB
        entry locally instantiated as an End.B6.Encaps SID, process the packet
        as per <xref target="upper"/>.<vspace blankLines="3" /></t> target="upper" format="default"/>.</t>
      </section>
      <section title="End.B6.Encaps.Red: numbered="true" toc="default">
        <name>End.B6.Encaps.Red: End.B6.Encaps with Reduced SRH"> SRH</name>
        <t>This is an optimization of the End.B6.Encaps behavior.</t>
        <t>End.B6.Encaps.Red reduces the size of the SRH by one SID by excluding the first SID in the SRH of the new IPv6 header. Thus, the first segment is only placed in the IPv6 Destination Address of the new IPv6 header header, and the packet is forwarded according to it.</t>
        <t>The SRH Last Entry field is set as defined in Section 4.1.1 of <xref
        sectionFormat="of" section="4.1.1" target="RFC8754" />.</t>
        format="default"/>.</t>
        <t>The SRH MAY <bcp14>MAY</bcp14> be omitted when the SRv6 Policy only contains one SID and there is no need to use any flag, tag tag, or TLV.</t>
      </section>
      <section title="End.BM: numbered="true" toc="default">
        <name>End.BM: Endpoint Bound to an SR-MPLS Policy"> Policy</name>
        <t>The "Endpoint bound to an SR-MPLS Policy" behavior ("End.BM" for short) is a variant of the End behavior.</t>
        <t>The End.BM behavior is required to express scalable traffic-engineering policies across multiple domains where some domains support the MPLS instantiation of Segment Routing. This is an SRv6 instantiation of an SR-MPLS Binding SID <xref target="RFC8402" />.</t> format="default"/>.</t>
        <t>Any SID instance of this behavior is associated with an SR-MPLS Policy B.</t>

                <t><vspace blankLines="2" />When
        <t>When N receives a packet whose IPv6 DA is S and S is a local End.BM SID, N does:</t>
                <figure><artwork><![CDATA[ does the following:</t>

<sourcecode type="pseudocode">
S01. When an SRH is processed {
S02.   If (Segments Left == 0) {
S03.      Stop processing the SRH, and proceed to process the next
             header in the packet, whose type is identified by
             the Next Header field in the routing header.
S04.   }
S05.   If (IPv6 Hop Limit <= &lt;= 1) {
S06.      Send an ICMP Time Exceeded message to the Source Address, Address
             with Code 0 (Hop limit exceeded in transit),
             interrupt packet processing processing, and discard the packet.
S07.   }
S08.   max_LE = (Hdr Ext Len / 2) - 1
S09.   If ((Last Entry > max_LE) or (Segments Left > (Last Last Entry+1)) {
S10.      Send an ICMP Parameter Problem to the Source Address, Address
             with Code 0 (Erroneous header field encountered), encountered)
             and Pointer set to the Segments Left field,
             interrupt packet processing processing, and discard the packet.

S11.   }
S12.   Decrement IPv6 Hop Limit by 1
S13.   Decrement Segments Left by 1
S14.   Update IPv6 DA with Segment List[Segments Left]
S15.   Push the MPLS label stack for B
S16.   Submit the packet to the MPLS engine for transmission
S17. }
                ]]></artwork></figure>

                <t><vspace blankLines="2" />When
</sourcecode>
        <t>When processing the Upper-layer Upper-Layer header of a packet matching a FIB entry locally instantiated as an End.BM SID, process the packet as per <xref target="upper"/>.</t> target="upper" format="default"/>.</t>
      </section>
      <section title="Flavors" anchor="BehFlavors"> anchor="BehFlavors" numbered="true" toc="default">
        <name>Flavors</name>
        <t>The Penultimate Segment Pop (PSP) of the SRH (PSP), SRH, Ultimate Segment Pop (USP) of the SRH (USP) SRH, and Ultimate Segment Decapsulation (USD) flavors are variants of the End, End.X End.X, and End.T behaviors. The End, End.X End.X, and End.T behaviors can support these flavors either individually or in combinations.</t>
        <section title="PSP: numbered="true" toc="default">
          <name>PSP: Penultimate Segment Pop of the SRH"> SRH</name>
          <section title="Guidelines"> numbered="true" toc="default">
            <name>Guidelines</name>

            <t>SR Segment Endpoint Nodes advertise the SIDs instantiated on
            them via control plane control-plane protocols as described in <xref target="cp" />.
            format="default"/>. Different behavior ids IDs are allocated for
            flavored and unflavored SIDs (see <xref target="endpoint_cp_types" />).</t>
            format="default"/>).</t>
            <t>An SR Segment Endpoint Node that offers both PSP PSP- and non-PSP flavored
            non-PSP-flavored behavior advertises them as two different
            SIDs.</t>
            <t>The SR Segment Endpoint Node only advertises the PSP flavor if
            the operator enables this capability at the node.</t>
            <t>The PSP operation is deterministically controlled by the SR Source Node.</t>
            source node.</t>
            <t>A PSP-flavored SID is used by the Source SR Node source node when it needs
            to instruct the penultimate SR Segment Endpoint Node listed in the
            SRH to remove the SRH from the IPv6 header.</t>
          </section>
          <section title="Definition"> numbered="true" toc="default">
            <name>Definition</name>
            <t>SR Segment Endpoint Nodes receive the IPv6 packet with the
            Destination Address field of the IPv6 Header header equal to its SID
            address.</t>
            <t>A penultimate SR Segment Endpoint Node is one that, as part of
            the SID processing, copies the last SID from the SRH into the IPv6
            Destination Address and decrements the Segments Left value from
            one to zero.</t>
            <t>The PSP operation only takes place at a penultimate SR Segment
            Endpoint Node and does not happen at any Transit Node. transit node. When a SID
            of PSP-flavor PSP flavor is processed at a non-penultimate SR Segment
            Endpoint Node, the PSP behavior is not performed as described in
            the pseudocode below since Segments Left would not be zero.</t>
            <t>The SRH processing of the End, End.X End.X, and End.T behaviors are
            modified: after the instruction "S14. Update IPv6 DA with Segment
            List[Segments Left]" is executed, the following instructions must
            be executed as well:</t>
                    <figure><artwork><![CDATA[
<sourcecode type="pseudocode">
S14.1.   If (Segments Left == 0) {
S14.2.      Update the Next Header field in the preceding header to
               the Next Header value from the SRH
S14.3.      Decrease the IPv6 header Payload Length by
               8*(Hdr Ext Len+1)
S14.4.      Remove the SRH from the IPv6 extension header chain
S14.5.   }
                    ]]></artwork></figure>
</sourcecode>
            <t>The usage of PSP does not increase the MTU of the IPv6 packet
            and hence does not have any impact on the PMTU Path MTU (PMTU)
            discovery mechanism.</t>
            <t>As a reminder, <xref target="RFC8754"/> target="RFC8754" sectionFormat="of"
            section="5" format="default"/> defines in section 5 the SR Deployment Model
            within the SR Domain <xref target="RFC8402"/>. target="RFC8402"
            format="default"/>. Within this framework, the Authentication
            Header (AH) is not used to secure the SRH as described in Section 7.5 of <xref target="RFC8754"/>.
            target="RFC8754" sectionFormat="of" section="7.5"
            format="default"/>. Hence, the discussion of applicability of PSP
            along with AH usage is beyond the scope of this document.</t>
            <t>In the context of this specification, the End, End.X End.X, and End.T
            behaviors with PSP do not contravene Section 4 of <xref target="RFC8200"/> target="RFC8200"
            sectionFormat="of" section="4" format="default"/> because the
            destination address of the incoming packet is the address of the
            node executing the behavior.</t>
          </section>

          <section title="Use-case"> numbered="true" toc="default">

            <name>Use Case</name>

            <t>One use-case use case for the PSP functionality is streamlining the operation of an egress border router.</t>
            <figure title="PSP use-case topology" anchor="fig-psp"><artwork><![CDATA[ anchor="fig-psp">
              <name>PSP Use Case Topology</name>
              <artwork name="" type="" align="left" alt=""><![CDATA[
  +----------------------------------------------------+
  |                                                    |
+-+-+         +--+         +--+         +--+         +-+-+
|iPE+-------->+R2+-------->+R3+-------->+R4+-------->+ePE|
| R1|         +--+         +--+         +--+         |R5 |
+-+-+ +-----+      +-----+      +-----+      +-----+ +-+-+
  |   |IPv6 |      |IPv6 |      |IPv6 |      |IPv6 |   |
  |   |DA=R3|      |DA=R3|      |DA=R5|      |DA=R5|   |
  |   +-----+      +-----+      +-----+      +-----+   |
  |   | SRH |      | SRH |      | IP  |      | IP  |   |
  |   |SL=1 |      |SL=1 |      +-----+      +-----+   |
  |   | R5  |      | R5  |                             |
  |   +-----+      +-----+                             |
  |   | IP  |      | IP  |                             |
  |   +-----+      +-----+                             |
  |                                                    |
  +----------------------------------------------------+
                        ]]></artwork></figure>
                        ]]></artwork>
            </figure>

         <t>In the above illustration, for a packet sent from iPE the ingress
         provider edge (iPE) to ePE, the egress provider edge (ePE), node R3 is an
         intermediate traffic engineering traffic-engineering waypoint and is the penultimate
         segment endpoint router; the this node that copies the last segment from the
         SRH into the IPv6 Destination Address and decrements segments left Segments Left to
         0. The SDN Software-Defined Networking (SDN) controller knows that no
         other node after R3 needs to inspect the SRH, and it instructs R3 to
         remove the exhausted SRH from the packet by using a PSP-flavored
         SID.</t>
            <t>The benefits for the egress PE are straightforward:
                            <list style="format -">
                                <t>as
            </t>
            <ul spacing="normal"><li>As part of the decapsulation process process, the
            egress PE is required to parse and remove fewer bytes from the packet.</t>
                                <t>if
            packet.</li>
              <li>If a lookup on an upper-layer IP header is required (e.g. (e.g.,
              per-VRF VPN), the header is more likely to be within the memory
              accessible to the lookup engine in the forwarding ASIC (Application-specific integrated circuit).</t>
                            </list>
                        </t>
              (Application-Specific Integrated Circuit).</li>
            </ul>
          </section>
        </section>
        <section title="USP: numbered="true" toc="default">
          <name>USP: Ultimate Segment Pop of the SRH"> SRH</name>
          <t>The SRH processing of the End, End.X End.X, and End.T behaviors are modified: modified; the instructions S02-S04 are substituted by the following ones:</t>
                    <figure><artwork><![CDATA[
<sourcecode type="pseudocode">
S02.     If (Segments Left == 0) {
S03.1.      Update the Next Header field in the preceding header to
               the Next Header value of the SRH
S03.2.      Decrease the IPv6 header Payload Length by
               8*(Hdr Ext Len+1)
S03.3.      Remove the SRH from the IPv6 extension header chain
S03.4.      Proceed to process the next header in the packet
S04.     }
                    ]]></artwork></figure>
</sourcecode>
 <t>One of the applications of the USP flavor is when a packet with an SRH is destined to an application on hosts with smartNICs ("Smart Network Interface Cards") implementing SRv6. The USP flavor is used to remove the consumed SRH from the extension header chain before sending the packet to the host.</t>
        </section>
        <section title="USD: numbered="true" toc="default">
          <name>USD: Ultimate Segment Decapsulation"> Decapsulation</name>
          <t>The Upper-layer Upper-Layer header processing of the End, End.X End.X, and End.T behaviors are modified as follows:</t>
                    <figure><artwork><![CDATA[
End:

<t>End:</t>
<sourcecode type="pseudocode">
S01. If (Upper-layer Header (Upper-Layer header type == 41(IPv6) ) {
S02.    Remove the outer IPv6 Header header with all its extension headers
S03.    Submit the packet to the egress IPv6 FIB lookup and for
           transmission to the new destination
S04. } Else if (Upper-layer Header (Upper-Layer header type == 4(IPv4) ) {
S05.    Remove the outer IPv6 Header header with all its extension headers
S06.    Submit the packet to the egress IPv4 FIB lookup and for
           transmission to the new destination
S07. Else {
S08.    Process as per Section 4.1.1
S09. }
                    ]]></artwork></figure>

                    <figure><artwork><![CDATA[
End.T:
</sourcecode>

<t>End.T:</t>
<sourcecode type="pseudocode">
S01. If (Upper-layer Header (Upper-Layer header type == 41(IPv6) ) {
S02.    Remove the outer IPv6 Header header with all its extension headers
S03.    Set the packet's associated FIB table to T
S04.    Submit the packet to the egress IPv6 FIB lookup and for
           transmission to the new destination
S05. } Else if (Upper-layer Header (Upper-Layer header type == 4(IPv4) ) {
S06.    Remove the outer IPv6 Header header with all its extension headers
S07.    Set the packet's associated FIB table to T
S08.    Submit the packet to the egress IPv4 FIB lookup and for
           transmission to the new destination
S09. Else {
S10.    Process as per Section 4.1.1
S11. }
                    ]]></artwork></figure>

                    <figure><artwork><![CDATA[
End.X:
</sourcecode>

<t>End.X:</t>
<sourcecode type="pseudocode">
S01. If (Upper-layer Header (Upper-Layer header type == 41(IPv6) ||
          Upper-layer Header
          Upper-Layer header type == 4(IPv4) ) {
S02.    Remove the outer IPv6 Header header with all its extension headers
S03.    Forward the exposed IP packet to the L3 adjacency J
S04. } Else {
S05.    Process as per Section 4.1.1
S06. }
                    ]]></artwork></figure>
</sourcecode>

          <t>One of the applications of the USD flavor is the case of TI-LFA a
          Topology Independent Loop-Free Alternate (TI-LFA) in P routers with
          encapsulation. The USD flavor allows the last SR Segment Endpoint Node
          in the repair path list to decapsulate the IPv6 header added at the
          TI-LFA Point of Local Repair and forward the inner packet.</t>
        </section>
      </section>
    </section>
    <section title="SR numbered="true" toc="default">
      <name>SR Policy Headend Behaviors"> Behaviors</name>
      <t>This section describes a set of SR SRv6 Policy Headend <xref target="RFC8402" /> format="default"/> behaviors.</t>
            <figure>
                <artwork><![CDATA[
H.Encaps        SR

<table anchor="headend">
  <name>SR Policy Headend Behaviors</name>

  <tbody>
    <tr>
      <td>H.Encaps
      </td>
      <td>SR Headend Behavior with Encapsulation in an SR Policy
H.Encaps.Red    H.Encaps
      </td>
    </tr>
    <tr>
      <td>H.Encaps.Red
      </td>
      <td>H.Encaps with Reduced Encapsulation
H.Encaps.L2     H.Encaps
      </td>
    </tr>
    <tr>
      <td>H.Encaps.L2
      </td>
      <td>H.Encaps Applied to Received L2 Frames
H.Encaps.L2.Red H.Encaps.Red
      </td>
    </tr>
    <tr>
      <td>H.Encaps.L2.Red
      </td>
      <td>H.Encaps.Red Applied to Received L2 Frames
            ]]></artwork>
            </figure>
      </td>
    </tr>
  </tbody>
</table>

      <t>This list is not exhaustive exhaustive, and future documents may define additional behaviors.</t>

            <?rfc needLines="10" ?>
      <section title="H.Encaps: numbered="true" toc="default">
        <name>H.Encaps: SR Headend with Encapsulation in an SRv6 Policy"> SR Policy</name>
        <t>Node N receives two packets P1=(A, B2) and P2=(A,B2)(B3, B2, B1;
        SL=1). B2 is neither a local address nor SID of N.</t>
        <t>Node N is configured with an IPv6 Address address T (e.g. (e.g., assigned to its
        loopback).</t> <t>N steers the transit packets P1 and P2 into an SR SRv6
        Policy with a Source Address T and a Segment segment list &lt;S1, S2,
        S3&gt;.</t>
        <t>The H.Encaps encapsulation behavior is defined as follows:</t>
                <figure><artwork><![CDATA[
<sourcecode type="pseudocode">
S01.   Push an IPv6 header with its own SRH
S02.   Set outer IPv6 SA = T and outer IPv6 DA to the first SID
          in the segment list
S03.   Set outer Payload Length, Traffic Class, Hop Limit Limit, and
          Flow Label fields
S04.   Set the outer Next-Header Next Header value
S05.   Decrement inner IPv6 Hop Limit or IPv4 TTL
S06.   Submit the packet to the IPv6 module for transmission to S1
                ]]></artwork></figure>
                <t>Note:<vspace blankLines="0" />S03:
</sourcecode>
<aside>
        <t>Note:</t>
<t>
S03: As described in <xref target="RFC2473" /> format="default"/> and <xref target="RFC6437"/>. <vspace blankLines="1" /></t>
target="RFC6437" format="default"/>. </t>
</aside>
        <t>After the H.Encaps behavior, P1' and P2' respectively look like:
                    <list style="format - ">
                        <t>(T,
        </t>
        <ul spacing="normal"><li>(T, S1) (S3, S2, S1; SL=2) (A, B2)</t>
                        <t>(T, B2)</li>
          <li>(T, S1) (S3, S2, S1; SL=2) (A, B2) (B3, B2, B1; SL=1)</t>
                    </list></t> SL=1)</li>
        </ul>
        <t>The received packet is encapsulated unmodified (with the exception of the IPv4 TTL or IPv6 Hop Limit that is decremented as described in <xref target="RFC2473"/>).</t> target="RFC2473" format="default"/>).</t>
        <t>The H.Encaps behavior is valid for any kind of Layer-3 L3 traffic. This behavior is commonly used for L3VPN with IPv4 and IPv6 deployments. It may be also used for TI-LFA <xref target="I-D.ietf-rtgwg-segment-routing-ti-lfa"/> target="I-D.ietf-rtgwg-segment-routing-ti-lfa" format="default"/> at the point Point of local repair.</t> Local Repair.</t>
        <t>The push of the SRH MAY <bcp14>MAY</bcp14> be omitted when the SRv6
        Policy only contains one segment and there is no need to use any flag, tag
        tag, or TLV.</t>
      </section>

            <?rfc needLines="10" ?>
      <section title="H.Encaps.Red: numbered="true" toc="default">
        <name>H.Encaps.Red: H.Encaps with Reduced Encapsulation"> Encapsulation</name>

        <t>The H.Encaps.Red behavior is an optimization of the H.Encaps behavior.</t>
        <t>H.Encaps.Red reduces the length of the SRH by excluding the first
        SID in the SRH of the pushed IPv6 header. The first SID is only placed
        in the Destination Address field of the pushed IPv6 header.</t>
        <t>After the H.Encaps.Red behavior, P1' and P2' respectively look like:
                    <list style="format - ">
                        <t>(T,
        </t>
        <ul spacing="normal"><li>(T, S1) (S3, S2; SL=2) (A, B2)</t>
                        <t>(T, B2)</li>
          <li>(T, S1) (S3, S2; SL=2) (A, B2) (B3, B2, B1; SL=1)</t>
                    </list></t> SL=1)</li>
        </ul>
        <t>The push of the SRH MAY <bcp14>MAY</bcp14> be omitted when the SRv6 Policy only contains one segment and there is no need to use any flag, tag tag, or TLV.</t>
      </section>

            <?rfc needLines="10" ?>
      <section title="H.Encaps.L2: numbered="true" toc="default">
        <name>H.Encaps.L2: H.Encaps Applied to Received L2 Frames"> Frames</name>
        <t>The H.Encaps.L2 behavior encapsulates a received Ethernet <xref target="IEEE.802.3_2018"/> target="IEEE.802.3_2018" format="default"/> frame and its attached VLAN header, if present, in an IPv6 packet with an SRH. The Ethernet frame becomes the payload of the new IPv6 packet.</t>
        <t>The Next Header field of the SRH MUST <bcp14>MUST</bcp14> be set to 143.</t>
        <t>The push of the SRH MAY <bcp14>MAY</bcp14> be omitted when the SRv6
        Policy only contains one segment and there is no need to use any flag, tag
        tag, or TLV.</t>
        <t>The encapsulating node MUST <bcp14>MUST</bcp14> remove the preamble (if
        any) and frame check sequence (FCS) from the Ethernet frame upon encapsulation
        encapsulation, and the decapsulating node MUST <bcp14>MUST</bcp14>
        regenerate, as required, the preamble and FCS before forwarding the
        Ethernet frame.</t>
      </section>

            <?rfc needLines="10" ?>
      <section title="H.Encaps.L2.Red: numbered="true" toc="default">
        <name>H.Encaps.L2.Red: H.Encaps.Red Applied to Received L2 frames"> Frames</name>
        <t>The H.Encaps.L2.Red behavior is an optimization of the H.Encaps.L2 behavior.</t>
        <t>H.Encaps.L2.Red reduces the length of the SRH by excluding the first SID in the SRH of the pushed IPv6 header. The first SID is only places placed in the Destination Address field of the pushed IPv6 header.</t>

        <t>The push of the SRH MAY <bcp14>MAY</bcp14> be omitted when the SRv6 Policy only contains one segment and there is no need to use any flag, tag tag, or TLV.</t>
      </section>
    </section>

        <?rfc needLines="10" ?>
    <section title="Counters"> numbered="true" toc="default">
      <name>Counters</name>
      <t>A node supporting this document SHOULD <bcp14>SHOULD</bcp14> implement a pair of traffic counters (one for packets and one for bytes) per local SID entry, for traffic that matched that SID and was processed successfully (i.e. (i.e., packets which that generate ICMP Error Messages or are dropped are not counted). The retrieval of these counters from MIB, NETCONF/YANG NETCONF/YANG, or any other data structure is outside the scope of this document.</t>
    </section>

        <?rfc needLines="5" ?>
    <section title="Flow-based Hash Computation" anchor="OpsFlowLabel" > numbered="true" toc="default">
      <name>Flow-Based Hash Computation</name>

      <t>When a flow-based selection within a set needs to be performed, the
      IPv6 Source Address, the IPv6 Destination Address Address, and the IPv6 Flow
      Label of the outer IPv6 header MUST <bcp14>MUST</bcp14> be included in the
      flow-based hash.</t>
      <t>This occurs when a may occur in any of the following scenarios:</t>
<ul>
<li>
      <t>A FIB lookup is performed and multiple ECMP paths
      exist to the updated destination address.</t>
            <t>This occurs when End.X,
</li>
     <li> <t>End.X, End.DX4, or End.DX6 are is bound to an array of adjacencies.</t>
            <t>This occurs when the adjacencies.</t></li>
<li>      <t>The packet is steered in an SR policy Policy whose selected
      path has multiple SID lists.</t> lists.</t></li>
</ul>

      <t>Additionally, any transit router in an SRv6 domain includes the outer
      flow label in its ECMP flow-based hash <xref target="RFC6437" />.</t>
      format="default"/>.</t>

    </section>

        <?rfc needLines="8" ?>
        <section title="Control Plane" anchor="cp">
    <section anchor="cp" numbered="true" toc="default">
      <name>Control Plane</name>
      <t>In an SDN environment, one expects the controller to explicitly
      provision the SIDs and/or discover them as part of a service discovery
      function. Applications residing on top of the controller could then
      discover the required SIDs and combine them to form a distributed
      network program.</t>
      <t>The concept of &quot;SRv6 network programming&quot; "SRv6 Network Programming" refers to the capability for of
      an application to encode any complex program as a set of individual
      functions distributed through the network. Some functions relate to
      underlay SLA, others to overlay/tenant, and others to complex
      applications residing in VM VMs and containers.</t>
      <t>While not necessary for an SDN control plane, the remainder of this
      section provides a high-level illustrative overview of how control-plane
      protocols may be involved with SRv6. Their specification is outside the
      scope of this document.</t>
      <section title="IGP" anchor="igp"> anchor="igp" numbered="true" toc="default">
        <name>IGP</name>
        <t>The End, End.T End.T, and End.X SIDs express topological behaviors and
        hence are expected to be signaled in the IGP together with the flavors
        PSP, USP USP, and USD. The IGP should also advertise the maximum SRv6 Maximum SID depth
        Depth (MSD) capability of the node for each type of SRv6 operation - --
        in particular, the SR source (e.g. (e.g., H.Encaps), intermediate endpoint (e.g. End, End.X)
        (e.g., End and End.X), and final endpoint (e.g. End.DX4, (e.g., End.DX4 and End.DT6)
        behaviors. These capabilities are factored in by an SR Source Node source node (or
        a controller) during the SR Policy computation.</t>
        <t>The presence of SIDs in the IGP does not imply any routing semantics to the addresses represented by these SIDs. The routing reachability to an IPv6 address is solely governed by the non-SID-related IGP prefix reachability information that includes locators. Routing is neither governed nor influenced in any way by a SID advertisement in the IGP.</t>
        <t>These SIDs provide important topological behaviors for the IGP to
        build FRR Fast Reroute (FRR) solutions based on TI-LFA <xref target="I-D.ietf-rtgwg-segment-routing-ti-lfa"/>
        target="I-D.ietf-rtgwg-segment-routing-ti-lfa" format="default"/> and
        for TE processes relying on an IGP topology database to build SR policies.</t>
        Policies.</t>
      </section>
      <section title="BGP-LS"> numbered="true" toc="default">
        <name>BGP-LS</name>
        <t>BGP-LS provides the functionality for topology discovery that
        includes the SRv6 capabilities of the nodes, their locators locators, and
        locally instantiated SIDs. This enables controllers or applications to
        build an inter-domain topology that can be used for computation of SR
        Policies using the SRv6 SIDs.</t>
      </section>
      <section title="BGP IP/VPN/EVPN"> numbered="true" toc="default">
        <name>BGP IP/VPN/EVPN</name>
        <t>The End.DX4, End.DX6, End.DT4, End.DT6, End.DT46, End.DX2,
        End.DX2V, End.DT2U End.DT2U, and End.DT2M SIDs can be signaled in BGP.</t>
        <t>In some scenarios scenarios, an egress PE advertising a VPN route might wish
        to abstract the specific behavior bound to the SID from the ingress PE
        and other routers in the network. In such case, the SID may be
        advertised using the Opaque SRv6 Endpoint Behavior codepoint defined
        in <xref target="endpoint_cp_types"/>. target="endpoint_cp_types" format="default"/>. The details of
        such control plane control-plane signaling mechanisms are out of the scope of this
        document.</t>
      </section>
      <section title="Summary"> numbered="true" toc="default">
        <name>Summary</name>
        <t>The following table summarizes which SID behaviors for SIDs that can
        may be signaled in which each respective control plane control-plane protocol.</t>

                <texttable

        <table anchor="localsid_signaling" title="SRv6 locally instantiated align="center">
          <name>SRv6 Locally Instantiated SIDs signaling">
                    <ttcol align="left"></ttcol>
                    <ttcol align="center">IGP</ttcol>
                    <ttcol align="center">BGP-LS</ttcol>
                    <ttcol Signaling</name>
          <thead>
            <tr>
              <th align="left"/>
              <th align="center">IGP</th>
              <th align="center">BGP-LS</th>
              <th align="center">BGP IP/VPN/EVPN</ttcol>

                    <c>End IP/VPN/EVPN</th>
            </tr>
          </thead>
          <tbody>
            <tr>
              <td align="left">End   (PSP, USP, USD)</c>
                    <c>X</c>
                    <c>X</c>
                    <c></c>
                    <c>End.X USD)</td>
              <td align="center">X</td>
              <td align="center">X</td>
              <td align="center"/>
            </tr>
            <tr>
              <td align="left">End.X (PSP, USP, USD)</c>
                    <c>X</c>
                    <c>X</c>
                    <c></c>
                    <c>End.T USD)</td>
              <td align="center">X</td>
              <td align="center">X</td>
              <td align="center"/>
            </tr>
            <tr>
              <td align="left">End.T (PSP, USP, USD)</c>
                    <c>X</c>
                    <c>X</c>
                    <c></c>
                    <c>End.DX6</c>
                    <c>X</c>
                    <c>X</c>
                    <c>X</c>
                    <c>End.DX4</c>
                    <c>X</c>
                    <c>X</c>
                    <c>X</c>
                    <c>End.DT6</c>
                    <c>X</c>
                    <c>X</c>
                    <c>X</c>
                    <c>End.DT4</c>
                    <c>X</c>
                    <c>X</c>
                    <c>X</c>
                    <c>End.DT46</c>
                    <c>X</c>
                    <c>X</c>
                    <c>X</c>
                    <c>End.DX2</c>
                    <c></c>
                    <c>X</c>
                    <c>X</c>
                    <c>End.DX2V</c>
                    <c></c>
                    <c>X</c>
                    <c>X</c>
                    <c>End.DT2U</c>
                    <c></c>
                    <c>X</c>
                    <c>X</c>
                    <c>End.DT2M</c>
                    <c></c>
                    <c>X</c>
                    <c>X</c>
                    <c>End.B6.Encaps</c>
                    <c></c>
                    <c>X</c>
                    <c></c>
                    <c>End.B6.Encaps.Red</c>
                    <c></c>
                    <c>X</c>
                    <c></c>
                    <c>End.B6.BM</c>
                    <c></c>
                    <c>X</c>
                    <c></c>
                </texttable> USD)</td>
              <td align="center">X</td>
              <td align="center">X</td>
              <td align="center"/>
            </tr>
            <tr>
              <td align="left">End.DX6</td>
              <td align="center">X</td>
              <td align="center">X</td>
              <td align="center">X</td>
            </tr>
            <tr>
              <td align="left">End.DX4</td>
              <td align="center">X</td>
              <td align="center">X</td>
              <td align="center">X</td>
            </tr>
            <tr>
              <td align="left">End.DT6</td>
              <td align="center">X</td>
              <td align="center">X</td>
              <td align="center">X</td>
            </tr>
            <tr>
              <td align="left">End.DT4</td>
              <td align="center">X</td>
              <td align="center">X</td>
              <td align="center">X</td>
            </tr>
            <tr>
              <td align="left">End.DT46</td>
              <td align="center">X</td>
              <td align="center">X</td>
              <td align="center">X</td>
            </tr>
            <tr>
              <td align="left">End.DX2</td>
              <td align="center"/>
              <td align="center">X</td>
              <td align="center">X</td>
            </tr>
            <tr>
              <td align="left">End.DX2V</td>
              <td align="center"/>
              <td align="center">X</td>
              <td align="center">X</td>
            </tr>
            <tr>
              <td align="left">End.DT2U</td>
              <td align="center"/>
              <td align="center">X</td>
              <td align="center">X</td>
            </tr>
            <tr>
              <td align="left">End.DT2M</td>
              <td align="center"/>
              <td align="center">X</td>
              <td align="center">X</td>
            </tr>
            <tr>
              <td align="left">End.B6.Encaps</td>
              <td align="center"/>
              <td align="center">X</td>
              <td align="center"/>
            </tr>
            <tr>
              <td align="left">End.B6.Encaps.Red</td>
              <td align="center"/>
              <td align="center">X</td>
              <td align="center"/>
            </tr>
            <tr>
              <td align="left">End.B6.BM</td>
              <td align="center"/>
              <td align="center">X</td>
              <td align="center"/>
            </tr>
          </tbody>
        </table>
        <t>The following table summarizes which SR Policy Headend capabilities are
        may be signaled in which signaling control-plane protocol.</t>

                <texttable
        <table anchor="transit_signaling" title="SRv6 align="center">
          <name>SRv6 Policy Headend behaviors signaling">
                    <ttcol align="left"></ttcol>
                    <ttcol align="center">IGP</ttcol>
                    <ttcol align="center">BGP-LS</ttcol>
                    <ttcol Behaviors Signaling</name>
          <thead>
            <tr>
              <th align="left"/>
              <th align="center">IGP</th>
              <th align="center">BGP-LS</th>
              <th align="center">BGP IP/VPN/EVPN</ttcol>

                    <c>H.Encaps</c>
                    <c>X</c>
                    <c>X</c>
                    <c></c>
                    <c>H.Encaps.Red</c>
                    <c>X</c>
                    <c>X</c>
                    <c></c>
                    <c>H.Encaps.L2</c>
                    <c></c>
                    <c>X</c>
                    <c></c>
                    <c>H.Encaps.L2.Red</c>
                    <c></c>
                    <c>X</c>
                    <c></c>
                </texttable> IP/VPN/EVPN</th>
            </tr>
          </thead>
          <tbody>
            <tr>
              <td align="left">H.Encaps</td>
              <td align="center">X</td>
              <td align="center">X</td>
              <td align="center"/>
            </tr>
            <tr>
              <td align="left">H.Encaps.Red</td>
              <td align="center">X</td>
              <td align="center">X</td>
              <td align="center"/>
            </tr>
            <tr>
              <td align="left">H.Encaps.L2</td>
              <td align="center"/>
              <td align="center">X</td>
              <td align="center"/>
            </tr>
            <tr>
              <td align="left">H.Encaps.L2.Red</td>
              <td align="center"/>
              <td align="center">X</td>
              <td align="center"/>
            </tr>
          </tbody>
        </table>
        <t>The previous table describes generic capabilities. It does not
        describe specific instantiated SR policies.</t> Policies.</t>
        <t>For example, a BGP-LS advertisement of H.Encaps behavior would
        describe the capability of node N to perform a H.Encaps
        behavior. Specifically, it would describe how many SIDs could be
        pushed by N without significant performance degradation.</t>
                <t><vspace blankLines="1" /></t>
        <t/>
        <t>As a reminder, an SR policy Policy is always assigned a Binding SID
        <xref target="RFC8402" />. BSIDs format="default"/>. Binding SIDs are also advertised
        in BGP-LS as shown in <xref target="localsid_signaling" />.
        format="default"/>. Hence, the <xref target="transit_signaling" />
        format="default"/> only focuses on the generic capabilities related to
        H.Encaps.</t>
      </section>
    </section>

        <?rfc needLines="10" ?>
    <section title="Security Considerations"> numbered="true" toc="default">
      <name>Security Considerations</name>

      <t>The security considerations for Segment Routing are discussed in
      <xref target="RFC8402"/>.
            Section 5 of target="RFC8402" format="default"/>.  <xref target="RFC8754"/> target="RFC8754"
      sectionFormat="of" section="5" format="default"/> describes the SR
      Deployment Model and the requirements for securing the SR Domain. The
      security considerations of [RFC8754] <xref target="RFC8754"/> also cover topics
      such as attack vectors and their mitigation mechanisms that also apply
      the behaviors introduced in this document.  Together, they describe the
      required security mechanisms that allow establishment of an SR domain of
      trust.  Having such a well-defined trust boundary is necessary in order
      to operate SRv6-based services for internal traffic while preventing any
      external traffic from accessing or exploiting the SRv6-based services.
      Care and rigor in IPv6 address allocation for use for SRv6 SID
      allocations and network infrastructure addresses, as distinct from IPv6
      addresses allocated for end-users/systems end users and systems (as illustrated in Section 5.1 of <xref target="RFC8754"/>),
      target="RFC8754" sectionFormat="of" section="5.1" format="default"/>),
      can provide the clear distinction between internal and external address
      space that is required to maintain the integrity and security of the
      SRv6 Domain.  Additionally, <xref target="RFC8754"/> target="RFC8754" format="default"/>
      defines an HMAC a Hashed Message Authentication Code (HMAC) TLV permitting SR
      Segment Endpoint Nodes in the SR domain to verify that the SRH applied to a
      packet was selected by an authorized party and to ensure that the
      segment list is not modified after generation, regardless of the number
      of segments in the segment list. When enabled by local configuration,
      HMAC processing occurs at the beginning of SRH processing as defined in
      <xref target="RFC8754"/> Section 2.1.2.1 .</t> target="RFC8754" sectionFormat="of" section="2.1.2.1"
      format="default"/>.</t>

      <t>This document introduces SRv6 Endpoint and SR Policy Headend
      behaviors for implementation on SRv6 capable SRv6-capable nodes in the network. The headend policy
      definition of the SR Policy Headend should be consistent with the
      specific behavior used and any local configuration (as specified in Section 4.1.1).
      <xref target="upper"/>). As such, this document does not introduce any
      new security considerations.</t>
      <t>The SID Behaviors behaviors specified in this document have the same HMAC TLV
      handling and mutability properties of with regard to the Flags, Tag, and Segment List
      field as the SID Behavior behavior specified in <xref target="RFC8754"/>.</t> target="RFC8754"
      format="default"/>.</t>

    </section>
    <section title="IANA Considerations">
            <section title="Ethernet numbered="true" toc="default">
      <name>IANA Considerations</name>

      <section anchor="ianaethernet" numbered="true" toc="default">
        <name>Ethernet Next Header Type" anchor="ianaethernet">
                <t>This document requests IANA to allocate, Type</name>
        <t>IANA has allocated "Ethernet" (value 143) in the &quot;Protocol Numbers&quot; "Assigned
        Internet Protocol Numbers" registry (https://www.iana.org/assignments/protocol-numbers/protocol-numbers.xhtml), a new value for &quot;Ethernet&quot; with the following definition: The value (see <eref brackets="angle"
        target="https://www.iana.org/assignments/protocol-numbers/"/>).
        Value 143 in the Next Header field of an IPv6 header or any extension
        header indicates that the payload is an Ethernet frame <xref
        target="IEEE.802.3_2018" />.</t>
                <t>IANA has done a temporary allocation of Protocol Number 143.</t> format="default"/>.</t>

      </section>
      <section title="SRv6 anchor="iana_registry" numbered="true" toc="default">
        <name>SRv6 Endpoint Behaviors Registry" anchor="iana_registry">
                <t>This document requests IANA to create Registry</name>
        <t>IANA has created a new top-level registry
        called &quot;Segment Routing Parameters&quot;. "Segment Routing" (see <eref brackets="angle"
        target="https://www.iana.org/assignments/segment-routing/"/>). This
        registry is being defined to serve serves as a top-level registry for keeping all other
        Segment Routing sub-registries.</t> subregistries.</t>
        <t>Additionally, IANA has created a new sub-registry &quot;SRv6 subregistry called "SRv6 Endpoint Behaviors&quot; is to be created Behaviors"
        under the top-level &quot;Segment Routing Parameters&quot; "Segment Routing" registry. This sub-registry
        subregistry maintains 16-bit identifiers for the SRv6 Endpoint
        behaviors. This registry is established to provide consistency for control plane
        control-plane protocols which that need to refer to these behaviors. These
        values are not encoded in the function bits within a SID.</t>

      <section anchor="iana_policy" numbered="true" toc="default">
        <name>Registration Procedures</name>

        <t>The range of the registry is 0-65535 (0x0000 - 0xFFFF) and has (0x0000-0xFFFF). The table below contains the following registration rules and allocation policies:</t>

                <texttable ranges and
        registration policies <xref
        target="RFC8126" format="default"/> for each:</t>
        <table anchor="endpoint_cp_codepoint_ranges" title="SRv6 Endpoint Behaviors Registry">
                    <ttcol align="left">Range</ttcol>
                    <ttcol align="center">Hex</ttcol>
                    <ttcol align="center">
          <name>Registration Procedures</name>
          <thead>
            <tr>
              <th align="left">Range</th>
              <th align="center">Range (Hex)</th>
              <th align="center">Registration procedure</ttcol>
                    <ttcol align="center">Notes</ttcol>

                    <c>0</c>
                    <c>0x0000</c>
                    <c>Reserved</c>
                    <c>Not to be allocated</c>

                    <c>1-32767</c>
                    <c>0x0001-0x7FFF</c>
                    <c>First Procedures</th>
              <th align="center">Note</th>
            </tr>
          </thead>
          <tbody>
            <tr>
              <td align="left">0</td>
              <td align="center">0x0000</td>
              <td align="center">Reserved</td>
              <td align="center">Not to be allocated</td>
            </tr>
            <tr>
              <td align="left">1-32767</td>
              <td align="center">0x0001-0x7FFF</td>
              <td align="center">First Come First Served <xref target="RFC8126" /></c>
                    <c></c>

                    <c>32768-34815</c>
                    <c>0x8000-0x87FF</c>
                    <c>Private Use <xref target="RFC8126" /></c>
                    <c></c>

                    <c>34816-65534</c>
                    <c>0x8800-0xFFFE</c>
                    <c>Reserved</c>
                    <c></c>

                    <c>65535</c>
                    <c>0xFFFF</c>
                    <c>Reserved</c>
                    <c>Opaque</c>
                </texttable>

                <section title="Initial Registrations"> Served</td>
              <td align="center"/>
            </tr>
            <tr>
              <td align="left">32768-34815</td>
              <td align="center">0x8000-0x87FF</td>
              <td align="center">Private Use</td>
              <td align="center"/>
            </tr>
            <tr>
              <td align="left">34816-65534</td>
              <td align="center">0x8800-0xFFFE</td>
              <td align="center">Reserved</td>
              <td align="center"/>
            </tr>
            <tr>
              <td align="left">65535</td>
              <td align="center">0xFFFF</td>
              <td align="center">Reserved</td>
              <td align="center">Opaque</td>
            </tr>
          </tbody>
        </table>
        </section>
        <section numbered="true" toc="default">
          <name>Initial Registrations</name>
          <t>The initial registrations for the sub-registry subregistry are as follows:</t>
                    <texttable
          <table anchor="endpoint_cp_types" title="IETF - SRv6 Endpoint Behaviors">
                        <ttcol align="left">Value</ttcol>
                        <ttcol align="center">Hex</ttcol>
                        <ttcol align="center">
            <name>Initial Registrations</name>
            <thead>
              <tr>
                <th align="left">Value</th>
                <th align="center">Hex</th>
                <th align="center">Endpoint behavior</ttcol>
                        <ttcol align="center">Reference</ttcol>
                        <c>0</c>
                        <c>0x0000</c>
                        <c>Reserved</c>
                        <c>Not to be allocated</c>
                        <c>1</c>
                        <c>0x0001</c>
                        <c>End</c>
                        <c>[This.ID]</c>
                        <c>2</c>
                        <c>0x0002</c>
                        <c>End with PSP</c>
                        <c>[This.ID]</c>
                        <c>3</c>
                        <c>0x0003</c>
                        <c>End with USP</c>
                        <c>[This.ID]</c>
                        <c>4</c>
                        <c>0x0004</c>
                        <c>End with PSP&amp;USP</c>
                        <c>[This.ID]</c>
                        <c>5</c>
                        <c>0x0005</c>
                        <c>End.X</c>
                        <c>[This.ID]</c>
                        <c>6</c>
                        <c>0x0006</c>
                        <c>End.X with PSP</c>
                        <c>[This.ID]</c>
                        <c>7</c>
                        <c>0x0007</c>
                        <c>End.X with USP</c>
                        <c>[This.ID]</c>
                        <c>8</c>
                        <c>0x0008</c>
                        <c>End.X with PSP&amp;USP</c>
                        <c>[This.ID]</c>
                        <c>9</c>
                        <c>0x0009</c>
                        <c>End.T</c>
                        <c>[This.ID]</c>
                        <c>10</c>
                        <c>0x000A</c>
                        <c>End.T with PSP</c>
                        <c>[This.ID]</c>
                        <c>11</c>
                        <c>0x000B</c>
                        <c>End.T with USP</c>
                        <c>[This.ID]</c>
                        <c>12</c>
                        <c>0x000C</c>
                        <c>End.T with PSP&amp;USP</c>
                        <c>[This.ID]</c>
                        <c>14</c>
                        <c>0x000E</c>
                        <c>End.B6.Encaps</c>
                        <c>[This.ID]</c>
                        <c>15</c>
                        <c>0x000F</c>
                        <c>End.BM</c>
                        <c>[This.ID]</c>
                        <c>16</c>
                        <c>0x0010</c>
                        <c>End.DX6</c>
                        <c>[This.ID]</c>
                        <c>17</c>
                        <c>0x0011</c>
                        <c>End.DX4</c>
                        <c>[This.ID]</c>
                        <c>18</c>
                        <c>0x0012</c>
                        <c>End.DT6</c>
                        <c>[This.ID]</c>
                        <c>19</c>
                        <c>0x0013</c>
                        <c>End.DT4</c>
                        <c>[This.ID]</c>
                        <c>20</c>
                        <c>0x0014</c>
                        <c>End.DT46</c>
                        <c>[This.ID]</c>
                        <c>21</c>
                        <c>0x0015</c>
                        <c>End.DX2</c>
                        <c>[This.ID]</c>
                        <c>22</c>
                        <c>0x0016</c>
                        <c>End.DX2V</c>
                        <c>[This.ID]</c>
                        <c>23</c>
                        <c>0x0017</c>
                        <c>End.DT2U</c>
                        <c>[This.ID]</c>
                        <c>24</c>
                        <c>0x0018</c>
                        <c>End.DT2M</c>
                        <c>[This.ID]</c>
                        <c>25</c>
                        <c>0x0019</c>
                        <c>Reserved</c>
                        <c>[This.ID]</c>
                        <c>27</c>
                        <c>0x001B</c>
                        <c>End.B6.Encaps.Red</c>
                        <c>[This.ID]</c>
                        <c>28</c>
                        <c>0x001C</c>
                        <c>End with USD</c>
                        <c>[This.ID]</c>
                        <c>29</c>
                        <c>0x001D</c>
                        <c>End with PSP&amp;USD</c>
                        <c>[This.ID]</c>
                        <c>30</c>
                        <c>0x001E</c>
                        <c>End with USP&amp;USD</c>
                        <c>[This.ID]</c>
                        <c>31</c>
                        <c>0x001F</c>
                        <c>End Behavior</th>
                <th align="center">Reference</th>
              </tr>
            </thead>
            <tbody>
              <tr>
                <td align="left">0</td>
                <td align="center">0x0000</td>
                <td align="center">Reserved</td>
                <td align="center"></td>
              </tr>
              <tr>
                <td align="left">1</td>
                <td align="center">0x0001</td>
                <td align="center">End</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">2</td>
                <td align="center">0x0002</td>
                <td align="center">End with PSP</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">3</td>
                <td align="center">0x0003</td>
                <td align="center">End with USP</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">4</td>
                <td align="center">0x0004</td>
                <td align="center">End with PSP &amp; USP</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">5</td>
                <td align="center">0x0005</td>
                <td align="center">End.X</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">6</td>
                <td align="center">0x0006</td>
                <td align="center">End.X with PSP</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">7</td>
                <td align="center">0x0007</td>
                <td align="center">End.X with USP</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">8</td>
                <td align="center">0x0008</td>
                <td align="center">End.X with PSP &amp; USP</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">9</td>
                <td align="center">0x0009</td>
                <td align="center">End.T</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">10</td>
                <td align="center">0x000A</td>
                <td align="center">End.T with PSP</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">11</td>
                <td align="center">0x000B</td>
                <td align="center">End.T with USP</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">12</td>
                <td align="center">0x000C</td>
                <td align="center">End.T with PSP &amp; USP</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">13</td>
                <td align="center">0x000D</td>
                <td align="center">Unassigned</td>
                <td align="center"></td>
              </tr>
              <tr>
                <td align="left">14</td>
                <td align="center">0x000E</td>
                <td align="center">End.B6.Encaps</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">15</td>
                <td align="center">0x000F</td>
                <td align="center">End.BM</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">16</td>
                <td align="center">0x0010</td>
                <td align="center">End.DX6</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">17</td>
                <td align="center">0x0011</td>
                <td align="center">End.DX4</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">18</td>
                <td align="center">0x0012</td>
                <td align="center">End.DT6</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">19</td>
                <td align="center">0x0013</td>
                <td align="center">End.DT4</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">20</td>
                <td align="center">0x0014</td>
                <td align="center">End.DT46</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">21</td>
                <td align="center">0x0015</td>
                <td align="center">End.DX2</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">22</td>
                <td align="center">0x0016</td>
                <td align="center">End.DX2V</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">23</td>
                <td align="center">0x0017</td>
                <td align="center">End.DT2U</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">24</td>
                <td align="center">0x0018</td>
                <td align="center">End.DT2M</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">25</td>
                <td align="center">0x0019</td>
                <td align="center">Reserved</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">26</td>
                <td align="center">0x001A</td>
                <td align="center">Unassigned</td>
                <td align="center"></td>
              </tr>
              <tr>
                <td align="left">27</td>
                <td align="center">0x001B</td>
                <td align="center">End.B6.Encaps.Red</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">28</td>
                <td align="center">0x001C</td>
                <td align="center">End with USD</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">29</td>
                <td align="center">0x001D</td>
                <td align="center">End with PSP &amp; USD</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">30</td>
                <td align="center">0x001E</td>
                <td align="center">End with USP &amp; USD</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">31</td>
                <td align="center">0x001F</td>
                <td align="center">End with PSP, USP  &amp; USD</c>
                        <c>[This.ID]</c>
                        <c>32</c>
                        <c>0x0020</c>
                        <c>End.X with USD</c>
                        <c>[This.ID]</c>
                        <c>33</c>
                        <c>0x0021</c>
                        <c>End.X with PSP&amp;USD</c>
                        <c>[This.ID]</c>
                        <c>34</c>
                        <c>0x0022</c>
                        <c>End.X with USP&amp;USD</c>
                        <c>[This.ID]</c>
                        <c>35</c>
                        <c>0x0023</c>
                        <c>End.X  USD</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">32</td>
                <td align="center">0x0020</td>
                <td align="center">End.X with USD</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">33</td>
                <td align="center">0x0021</td>
                <td align="center">End.X with PSP &amp; USD</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">34</td>
                <td align="center">0x0022</td>
                <td align="center">End.X with USP &amp; USD</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">35</td>
                <td align="center">0x0023</td>
                <td align="center">End.X with PSP, USP &amp; USD</c>
                        <c>[This.ID]</c>
                        <c>36</c>
                        <c>0x0024</c>
                        <c>End.T with USD</c>
                        <c>[This.ID]</c>
                        <c>37</c>
                        <c>0x0025</c>
                        <c>End.T with PSP&amp;USD</c>
                        <c>[This.ID]</c>
                        <c>38</c>
                        <c>0x0026</c>
                        <c>End.T with USP&amp;USD</c>
                        <c>[This.ID]</c>
                        <c>39</c>
                        <c>0x0027</c>
                        <c>End.T USD</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">36</td>
                <td align="center">0x0024</td>
                <td align="center">End.T with USD</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">37</td>
                <td align="center">0x0025</td>
                <td align="center">End.T with PSP &amp; USD</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">38</td>
                <td align="center">0x0026</td>
                <td align="center">End.T with USP &amp; USD</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">39</td>
                <td align="center">0x0027</td>
                <td align="center">End.T with PSP, USP &amp; USD</c>
                        <c>[This.ID]</c>
                        <c>40-32766</c>
                        <c></c>
                        <c>Unassigned</c>
                        <c></c>
                        <c>32767</c>
                        <c>0x7FFF</c>
                        <c>The USD</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">40-32766</td>
                <td align="center">0x0028-0x7FFE</td>
                <td align="center">Unassigned</td>
                <td align="center"/>
              </tr>
              <tr>
                <td align="left">32767</td>
                <td align="center">0x7FFF</td>
                <td align="center">The SID defined in RFC8754</c>
                        <c>[This.ID] <xref target="RFC8754" /></c>
                        <c>32768-65534</c>
                        <c></c>
                        <c>Reserved</c>
                        <c></c>
                        <c>65535</c>
                        <c>0xFFFF</c>
                        <c>Opaque</c>
                        <c>[This.ID]</c>
                    </texttable> RFC 8754</td>
                <td align="center">RFC 8986, RFC 8754</td>
              </tr>
              <tr>
                <td align="left">32768-34815</td>
                <td align="center">0x8000-0x87FF</td>
                <td align="center">Reserved for Private Use</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">34816-65534</td>
                <td align="center">0x8800-0xFFFE</td>
                <td align="center">Reserved</td>
                <td align="center">RFC 8986</td>
              </tr>
              <tr>
                <td align="left">65535</td>
                <td align="center">0xFFFF</td>
                <td align="center">Opaque</td>
                <td align="center">RFC 8986</td>
              </tr>
            </tbody>
          </table>
        </section>
      </section>
    </section>

        <?rfc needLines="1" ?>

  </middle>
  <back>

<displayreference target="I-D.filsfils-spring-srv6-net-pgm-illustration" to="SRV6-NET-PGM-ILLUST"/>
<displayreference target="I-D.ietf-rtgwg-segment-routing-ti-lfa" to="SR-TI-LFA"/>

    <references>
      <name>References</name>
      <references>
        <name>Normative References</name>

        <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.2119.xml"/>
        <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.8174.xml"/>
        <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.8754.xml"/>
        <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.2473.xml"/>
        <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.8200.xml"/>
        <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.8402.xml"/>
        <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.6437.xml"/>

        <reference anchor="IEEE.802.3_2018" target="https://ieeexplore.ieee.org/document/8457469">
          <front>
            <title>IEEE Standard for Ethernet</title>
            <author>
              <organization>IEEE</organization>
            </author>
            <date day="31" month="August" year="2018"/>
          </front>

          <seriesInfo name="DOI" value="10.1109/IEEESTD.2018.8457469"/>
<refcontent>IEEE 802.3-2018</refcontent>
        </reference>

      </references>
      <references>
        <name>Informative References</name>
        <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.4364.xml"/>

<reference anchor='I-D.filsfils-spring-srv6-net-pgm-illustration'>
<front>
<title>Illustrations for SRv6 Network Programming</title>

<author initials='C' surname='Filsfils' fullname='Clarence Filsfils'>
    <organization />
</author>

<author initials='P' surname='Camarillo' fullname='Pablo Camarillo' role="editor">
    <organization />
</author>

<author initials='Z' surname='Li' fullname='Zhenbin Li'>
    <organization />
</author>

<author initials='S' surname='Matsushima' fullname='Satoru Matsushima'>
    <organization />
</author>

<author initials='B' surname='Decraene' fullname='Bruno Decraene'>
    <organization />
</author>

<author initials='D' surname='Steinberg' fullname='Dirk Steinberg'>
    <organization />
</author>

<author initials='D' surname='Lebrun' fullname='David Lebrun'>
    <organization />
</author>

<author initials='R' surname='Raszuk' fullname='Robert Raszuk'>
    <organization />
</author>

<author initials='J' surname='Leddy' fullname='John Leddy'>
    <organization />
</author>

<date month='September' day='25'  year='2020' />

</front>

<seriesInfo name='Internet-Draft' value='draft-filsfils-spring-srv6-net-pgm-illustration-03' />
<format type='TXT'
        target='http://www.ietf.org/internet-drafts/draft-filsfils-spring-srv6-net-pgm-illustration-03.txt' />
</reference>

        <xi:include href="https://datatracker.ietf.org/doc/bibxml3/reference.I-D.ietf-rtgwg-segment-routing-ti-lfa.xml"/>

        <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.8214.xml"/>
        <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.7432.xml"/>
        <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.4664.xml"/>
        <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.4762.xml"/>
        <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.8126.xml"/>
        <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.4761.xml"/>
        <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.8317.xml"/>
        <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.4193.xml"/>
      </references>
    </references>

    <section anchor="Acknowledgements" title="Acknowledgements"> numbered="false" toc="default">
      <name>Acknowledgements</name>
      <t>The authors would like to acknowledge Stefano Previdi, Dave Barach, Mark Townsley, Peter Psenak, Thierry Couture, Kris Michielsen, Paul Wells, Robert Hanzl, Dan Ye, Gaurav Dawra, Faisal Iqbal, Jaganbabu Rajamanickam, David Toscano, Asif Islam, Jianda Liu, Yunpeng Zhang, Jiaoming Li, Narendra A.K, Mike <contact fullname="Stefano Previdi"/>, <contact fullname="Dave Barach"/>, <contact fullname="Mark Townsley"/>, <contact fullname="Peter Psenak"/>, <contact fullname="Thierry Couture"/>, <contact fullname="Kris Michielsen"/>, <contact fullname="Paul Wells"/>, <contact fullname="Robert Hanzl"/>, <contact fullname="Dan Ye"/>, <contact fullname="Gaurav Dawra"/>, <contact fullname="Faisal Iqbal"/>, <contact fullname="Jaganbabu Rajamanickam"/>, <contact fullname="David Toscano"/>, <contact fullname="Asif Islam"/>, <contact fullname="Jianda Liu"/>, <contact fullname="Yunpeng Zhang"/>, <contact fullname="Jiaoming Li"/>, <contact fullname="Narendra A.K"/>, <contact fullname="Mike Mc Gourty, Bhupendra Yadav, Sherif Toulan, Satish Damodaran, John Bettink, Kishore Gourty"/>, <contact fullname="Bhupendra Yadav"/>, <contact fullname="Sherif Toulan"/>, <contact fullname="Satish Damodaran"/>, <contact fullname="John Bettink"/>, <contact fullname="Kishore Nandyala Veera Venk, Jisu Bhattacharya, Saleem Hafeez and Brian Carpenter.</t>
        </section>

        <?rfc needLines="1" ?>
        <section title="Contributors">

            <t>Daniel Bernier<vspace blankLines="0" />
            Bell Canada<vspace blankLines="0" />
            Canada</t>
            <t>Email: daniel.bernier@bell.ca<vspace blankLines="0" /></t>

            <t>Dirk Steinberg<vspace blankLines="0" />
            Lapishills Venk"/>, <contact fullname="Jisu Bhattacharya"/>, <contact fullname="Saleem Hafeez"/>, and <contact fullname="Brian Carpenter"/>.</t>
    </section>
    <section numbered="false" toc="default">
      <name>Contributors</name>

<contact fullname="Daniel Bernier" >
        <organization>Bell Canada</organization>
        <address>
          <postal>
            <country>Canada</country>
            </postal>
          <email>daniel.bernier@bell.ca</email>
          </address>
	  </contact>

<contact fullname="Dirk Steinberg" >
        <organization>Lapishills Consulting Limited<vspace blankLines="0" />
            Cyprus</t>
            <t>Email: dirk@lapishills.com<vspace blankLines="0" /></t>

            <t>Robert Raszuk<vspace blankLines="0" />
            Bloomberg LP<vspace blankLines="0" />
            United Limited</organization>
        <address>
          <postal>
            <city></city>
            <country>Cyprus</country>
          </postal>
          <email>dirk@lapishills.com</email>
        </address>
</contact>

<contact fullname="Robert Raszuk" >
        <organization>Bloomberg LP</organization>
        <address>
          <postal>
            <city></city>
            <country>United States of America</t>
            <t>Email: robert@raszuk.net<vspace blankLines="0" /></t>

            <t>Bruno Decraene<vspace blankLines="0" />
            Orange<vspace blankLines="0" />
            France</t>
            <t>Email: bruno.decraene@orange.com<vspace blankLines="0" /></t>

            <t>Bart Peirens<vspace blankLines="0" />
            Proximus<vspace blankLines="0" />
            Belgium</t>
            <t>Email: bart.peirens@proximus.com<vspace blankLines="0" /></t>

            <t>Hani Elmalky<vspace blankLines="0" />
            Google<vspace blankLines="0" />
            United America</country>
          </postal>
          <email>robert@raszuk.net</email>
        </address>
</contact>

<contact fullname="Bruno Decraene" >
        <organization>Orange</organization>
        <address>
          <postal>
            <city></city>
            <country>France</country>
          </postal>
          <email>bruno.decraene@orange.com</email>
        </address>
</contact>

<contact fullname="Bart Peirens" >
        <organization>Proximus</organization>
        <address>
          <postal>
            <city></city>
            <country>Belgium</country>
          </postal>
          <email>bart.peirens@proximus.com</email>
        </address>
</contact>

<contact fullname="Hani Elmalky" >
        <organization>Google</organization>
        <address>
          <postal>
            <city></city>
            <country>United States of America</t>
            <t>Email: helmalky@google.com<vspace blankLines="0" /></t>

            <t>Prem Jonnalagadda<vspace blankLines="0" />
            Barefoot Networks<vspace blankLines="0" />
            United America</country>
          </postal>
          <email>helmalky@google.com</email>
        </address>
</contact>

<contact fullname="Prem Jonnalagadda" >
        <organization>Barefoot Networks</organization>
        <address>
          <postal>
            <city></city>
            <country>United States of America</t>
            <t>Email: prem@barefootnetworks.com<vspace blankLines="0" /></t>

            <t>Milad Sharif<vspace blankLines="0" />
            SambaNova Systems<vspace blankLines="0" />
            United America</country>
          </postal>
          <email>prem@barefootnetworks.com</email>
        </address>
</contact>

<contact fullname="Milad Sharif" >
        <organization>SambaNova Systems</organization>
        <address>
          <postal>
            <city></city>
            <country>United States of America</t>
            <t>Email: milad.sharif@sambanova.ai<vspace blankLines="0" /></t>

            <t>David Lebrun<vspace blankLines="0" />
            Google<vspace blankLines="0" />
            Belgium</t>
            <t>Email: dlebrun@google.com<vspace blankLines="0" /></t>

            <t>Stefano Salsano<vspace blankLines="0" />
            Universita America</country>
          </postal>
          <email>milad.sharif@sambanova.ai</email>
        </address>
</contact>

<contact fullname="David Lebrun" >
        <organization>Google</organization>
        <address>
          <postal>
            <city></city>
            <country>Belgium</country>
          </postal>
          <email>dlebrun@google.com</email>
        </address>
</contact>

<contact fullname="Stefano Salsano" >
        <organization>Universita di Roma "Tor Vergata"<vspace blankLines="0" />
            Italy</t>
            <t>Email: stefano.salsano@uniroma2.it<vspace blankLines="0" /></t>

            <t>Ahmed AbdelSalam<vspace blankLines="0" />
            Gran Vergata"</organization>
        <address>
          <postal>
            <city></city>
            <country>Italy</country>
          </postal>
          <email>stefano.salsano@uniroma2.it</email>
        </address>
</contact>

<contact fullname="Ahmed AbdelSalam" >
        <organization>Gran Sasso Science Institute<vspace blankLines="0" />
            Italy</t>
            <t>Email: ahmed.abdelsalam@gssi.it</t>

            <t>Gaurav Naik<vspace blankLines="0" />
            Drexel University<vspace blankLines="0" />
            United Institute</organization>
        <address>
          <postal>
            <city></city>
            <country>Italy</country>
          </postal>
          <email>ahmed.abdelsalam@gssi.it</email>
        </address>
</contact>

<contact fullname="Gaurav Naik" >
        <organization>Drexel University</organization>
        <address>
          <postal>
            <city></city>
            <country>United States of America</t>
            <t>Email: gn@drexel.edu<vspace blankLines="0" /></t>

            <t>Arthi Ayyangar<vspace blankLines="0" />
            Arrcus, Inc<vspace blankLines="0" />
            United America</country>
          </postal>
          <email>gn@drexel.edu</email>
        </address>
</contact>

<contact fullname="Arthi Ayyangar" >
        <organization>Arrcus, Inc</organization>
        <address>
          <postal>
            <city></city>
            <country>United States of America</t>
            <t>Email: arthi@arrcus.com<vspace blankLines="0" /></t>

            <t>Satish Mynam<vspace blankLines="0" />
            Arrcus, Inc<vspace blankLines="0" />
            United America</country>
          </postal>
          <email>arthi@arrcus.com</email>
        </address>
</contact>

<contact fullname="Satish Mynam" >
        <organization>Arrcus, Inc</organization>
        <address>
          <postal>
            <city></city>
            <country>United States of America</t>
            <t>Email: satishm@arrcus.com<vspace blankLines="0" /></t>

            <t>Wim Henderickx<vspace blankLines="0" />
            Nokia<vspace blankLines="0" />
            Belgium</t>
            <t>Email: wim.henderickx@nokia.com<vspace blankLines="0" /></t>

            <t>Shaowen Ma<vspace blankLines="0" />
            Juniper<vspace blankLines="0" />
            Singapore</t>
            <t>Email: mashao@juniper.net<vspace blankLines="0" /></t>

            <t>Ahmed Bashandy<vspace blankLines="0" />
            Individual<vspace blankLines="0" />
            United America</country>
          </postal>
          <email>satishm@arrcus.com</email>
        </address>
</contact>

<contact fullname="Wim Henderickx" >
        <organization>Nokia</organization>
        <address>
          <postal>
            <city></city>
            <country>Belgium</country>
          </postal>
          <email>wim.henderickx@nokia.com</email>
        </address>
</contact>

<contact fullname="Shaowen Ma" >
        <organization>Juniper</organization>
        <address>
          <postal>
            <city></city>
            <country>Singapore</country>
          </postal>
          <email>mashao@juniper.net</email>
        </address>
</contact>

<contact fullname="Ahmed Bashandy">
        <organization>Individual</organization>
        <address>
          <postal>
            <city></city>
            <country>United States of America</t>
            <t>Email: abashandy.ietf@gmail.com<vspace blankLines="0" /></t>

            <t>Francois Clad<vspace blankLines="0" />
            Cisco America</country>
          </postal>
          <email>abashandy.ietf@gmail.com</email>
        </address>
</contact>

<contact fullname="Francois Clad">
        <organization>Cisco Systems, Inc.<vspace blankLines="0" />
            France</t>
            <t>Email: fclad@cisco.com<vspace blankLines="0" /></t>

            <t>Kamran Raza<vspace blankLines="0" />
            Cisco Inc.</organization>
        <address>
          <postal>
            <city></city>
            <country>France</country>
          </postal>
          <email>fclad@cisco.com</email>
        </address>
</contact>

<contact fullname="Kamran Raza">
        <organization>Cisco Systems, Inc.<vspace blankLines="0" />
            Canada</t>
            <t>Email: skraza@cisco.com<vspace blankLines="0" /></t>

            <t>Darren Dukes<vspace blankLines="0" />
            Cisco Inc.</organization>
        <address>
          <postal>
            <city></city>
            <country>Canada</country>
          </postal>
          <email>skraza@cisco.com</email>
        </address>
</contact>

<contact fullname="Darren Dukes">
        <organization>Cisco Systems, Inc.<vspace blankLines="0" />
            Canada</t>
            <t>Email: ddukes@cisco.com<vspace blankLines="0" /></t>

            <t>Patrice Brissete <vspace blankLines="0" />
            Cisco Inc.</organization>
        <address>
          <postal>
            <city></city>
            <country>Canada</country>
          </postal>
          <email>ddukes@cisco.com</email>
        </address>
</contact>

<contact fullname="Patrice Brissete" >
        <organization>Cisco Systems, Inc.<vspace blankLines="0" />
            Canada</t>
            <t>Email: pbrisset@cisco.com<vspace blankLines="0" /></t>

            <t>Zafar Ali<vspace blankLines="0" />
            Cisco Inc.</organization>
        <address>
          <postal>
            <city></city>
            <country>Canada</country>
          </postal>
          <email>pbrisset@cisco.com</email>
        </address>
</contact>

<contact fullname="Zafar Ali" >
        <organization>Cisco Systems, Inc.<vspace blankLines="0" />
            United Inc.</organization>
        <address>
          <postal>
            <city></city>
            <country>United States of America</t>
            <t>Email: zali@cisco.com</t>

            <t>Ketan Talaulikar<vspace blankLines="0" />
            Cisco America</country>
          </postal>
          <email>zali@cisco.com</email>
        </address>
</contact>

<contact fullname="Ketan Talaulikar" >
        <organization>Cisco Systems, Inc.<vspace blankLines="0" />
            India</t>
            <t>Email: ketant@cisco.com</t> Inc.</organization>
        <address>
          <postal>
            <city></city>
            <country>India</country>
          </postal>
          <email>ketant@cisco.com</email> </address> </contact> </section>
    </middle>
    <back>
        <references title="Normative References">
            <!--?rfc include="http://xml.resource.org/public/rfc/bibxml/reference.RFC.2119.xml"?-->
            &RFC2119;
            &RFC8174;
            &RFC8754;
            &RFC2473;
            &RFC8200;
            &RFC8402;
            &RFC6437;
            <reference anchor="IEEE.802.3_2018" target="https://ieeexplore.ieee.org/document/8457469">
                <front>
                    <title>802.3-2018</title>
                    <author>
                        <organization>IEEE</organization>
                    </author>
                    <date day="31" month="August" year="2018"/>
                    <abstract>
                        <t>Ethernet local area network operation is specified for selected speeds of operation from 1 Mb/s to 400 Gb/s using a common media access control (MAC) specification and management information base (MIB). The Carrier Sense Multiple Access with Collision Detection (CSMA/CD) MAC protocol specifies shared medium (half duplex) operation, as well as full duplex operation. Speed specific Media Independent Interfaces (MIIs) allow use of selected Physical Layer devices (PHY) for operation over coaxial, twisted pair or fiber optic cables, or electrical backplanes. System considerations for multisegment shared access networks describe the use of Repeaters that are defined for operational speeds up to 1000 Mb/s. Local Area Network (LAN) operation is supported at all speeds. Other specified capabilities include: various PHY types for access networks, PHYs suitable for metropolitan area network applications, and the provision of power over selected twisted pair PHY types.</t>
                    </abstract>
                </front>
                <seriesInfo name="IEEE" value="802.3-2018"/>
                <seriesInfo name="DOI" value="10.1109/IEEESTD.2018.8457469"/>
            </reference>
        </references>
        <references title="Informative References">
            &RFC4364;
            &NET_PGM_ILL;
            &TILFA;
            &RFC8214;
            &RFC7432;
            &RFC4664;
            &RFC4762;
            &RFC8126;
            &RFC4761;
            &RFC8317;
            &RFC4193;
        </references>

  </back>
</rfc>