Network Working Group M. Chen Internet-Draft Huawei Intended status: Standards Track G. Mirsky Expires: August 17, 2014 Ericsson February 13, 2014 Extensions to ISIS for Source Label Distribution draft-chen-isis-source-label-distribution-00 Abstract An MPLS Source Label (SL) is defined to identify a node that is (one of) the ingress LSRs to a specific LSP. This document defines extensions to ISIS protocol for distribution of the mapping of an MPLS Source Label to an specific LSR. Therefore, the egress and intermediate LSRs can determine from which LSR an MPLS packet is sent. This document also defines ISIS extensions to advertise the Source Label Capability (SLC) of each LSR that indicates whether an LSR can process the Source Label. With the SLC, an ingress LSR can determine whether it is allowed to insert a Source Label into the label stack for a specific LSP. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on August 17, 2014. Chen & Mirsky Expires August 17, 2014 [Page 1] Internet-Draft ISIS Source Label Distribution February 2014 Copyright Notice Copyright (c) 2014 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Extensions to ISIS . . . . . . . . . . . . . . . . . . . . . 3 3. Elements of Procedure . . . . . . . . . . . . . . . . . . . . 3 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 5. Security Considerations . . . . . . . . . . . . . . . . . . . 4 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 7.1. Normative References . . . . . . . . . . . . . . . . . . 4 7.2. Informative References . . . . . . . . . . . . . . . . . 4 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction The MPLS Source Label is defined in [I-D.chen-mpls-source-label], it is used to identify (one of) the ingress LSR(s) of an LSP. To identify from where an MPLS packet is sent, a pure Source Label (SL) is not enough, it needs to know to which LSR a SL is correlated. Therefore, there needs a mechanism to distribute the mapping information between a SL and its correlated LSR. In addition, for an ingress LSR, before inserting a SL in the label stack of an LSP, it needs to know whether the egress LSR has the capability to process the SL, otherwise the packet will be dropped at the egress LSR. The capability is called Source Label Capability (SLC). This document defines extensions to ISIS [RFC1195] protocol to distribute SL to LSR mapping and advertise the SLC of each LSR. Chen & Mirsky Expires August 17, 2014 [Page 2] Internet-Draft ISIS Source Label Distribution February 2014 2. Extensions to ISIS The Source Label sub-TLV is used to distribute the Source Label to LSR mapping and the SLC. The Source Label sub-TLV is advertised within an IS-IS CAPABILITY TLV that is defined in [RFC4971], it has the following format: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | System ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | System ID(cond.) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved | Source Label | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1 - ISIS Source Label sub-TLV format The value of Type field is TBD1. The Length field defines the length of the Reserved and Source Label in octets, the value is 4. The Source Label field contains the Source Label that identifies the advertising LSR. 3. Elements of Procedure The Source Label sub-TLV is carried within an IS-IS CAPABILITY TLV defined in [RFC4971]. All the procedures that defined in [RFC4971] are inherited here. The flooding scope of the Source Label sub-TLV can be either area local or entire IGP domain. The flooding scope is controlled by the S flag in the IS-IS Router Capability TLV [RFC4971]. If the flooding scope is area local, the Source Label sub-TLV MUST be carried within an IS-IS Router Capability TLV with the S flag clear. If the flooding scope is the entire IGP domain, the Source Label sub-TLV MUST be carried within an IS-IS Router Capability TLV with the S flag set. The Source Label sub-TLV is an optional sub-TLV. Upon receipt the sub-TLV, a router will silently ignore the sub-TLV as defined in [RFC4971] if it does not support it. If Source Label sub-TLV is not present that MUST be interpreted as signaling of non-support of SLC Chen & Mirsky Expires August 17, 2014 [Page 3] Internet-Draft ISIS Source Label Distribution February 2014 by the LSR. Presence of a Source Label sub-TLV MUST be interpreted as support of SLC by the LSR. A Source Label sub-TLV MUST appear only one time in an LSP. 4. IANA Considerations IANA is requested to assign a new sub-TLV code point for the Source Label sub-TLV carried within the IS-IS Router Capability TLV. Type Value TLV Name Reference ---------- --------------- -------------- TBD1 Source Label (this document) 5. Security Considerations TBD. 6. Acknowledgements 7. References 7.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC4971] Vasseur, JP., Shen, N., and R. Aggarwal, "Intermediate System to Intermediate System (IS-IS) Extensions for Advertising Router Information", RFC 4971, July 2007. 7.2. Informative References [I-D.chen-mpls-source-label] Chen, M., Building, K., Li, Z., and L. Fang, "MultiProtocol Label Switching (MPLS) Source Label", draft-chen-mpls-source-label-01 (work in progress), October 2013. [RFC1195] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and dual environments", RFC 1195, December 1990. Authors' Addresses Mach(Guoyi) Chen Huawei Email: mach.chen@huawei.com Chen & Mirsky Expires August 17, 2014 [Page 4] Internet-Draft ISIS Source Label Distribution February 2014 Greg Mirsky Ericsson Email: Gregory.mirsky@ericsson.com Chen & Mirsky Expires August 17, 2014 [Page 5]