Extensions to IS-IS for Layer-2 Systems
RFC 6165

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Internet Engineering Task Force (IETF)                       A. Banerjee
Request for Comments: 6165                                 Cisco Systems
Category: Standards Track                                        D. Ward
ISSN: 2070-1721                                         Juniper Networks
                                                              April 2011

                Extensions to IS-IS for Layer-2 Systems

Abstract

   This document specifies the Intermediate System to Intermediate
   System (IS-IS) extensions necessary to support link state routing for
   any protocols running directly over Layer-2.  While supporting this
   concept involves several pieces, this document only describes
   extensions to IS-IS.  Furthermore, the Type, Length, Value pairs
   (TLVs) described in this document are generic Layer-2 additions, and
   specific ones as needed are defined in the IS-IS technology-specific
   extensions.  We leave it to the systems using these IS-IS extensions
   to explain how the information carried in IS-IS is used.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc6165.

Banerjee & Ward              Standards Track                    [Page 1]
RFC 6165                      Layer-2-IS-IS                   April 2011

Copyright Notice

   Copyright (c) 2011 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. Overview ........................................................2
      1.1. Terminology ................................................3
   2. TLV Enhancements to IS-IS .......................................3
      2.1. Multi-Topology-Aware Port Capability TLV ...................3
      2.2. The MAC-Reachability TLV ...................................4
   3. Acknowledgements ................................................5
   4. Security Considerations .........................................5
   5. IANA Considerations .............................................5
   6. References ......................................................6
      6.1. Normative References .......................................6
      6.2. Informative References .....................................6

1.  Overview

   There are a number of systems (for example, [RBRIDGES], [802.1aq],
   and [OTV]) that use Layer-2 addresses carried in a link state routing
   protocol, specifically Intermediate System to Intermediate System
   [IS-IS] [RFC1195], to provide true Layer-2 routing.  In almost all
   the technologies mentioned above, classical Layer-2 packets are
   encapsulated with an outer header.  The outer header format varies
   across all these technologies.  This outer header is used to route
   the encapsulated packets to their destination.

   Each Intermediate System (IS) advertises one or more IS-IS Link State
   Protocol Data Units (PDUs) with routing information.  Each Link State
   PDU (LSP) is composed of a fixed header and a number of tuples, each
   consisting of a Type, a Length, and a Value.  Such tuples are

Banerjee & Ward              Standards Track                    [Page 2]
RFC 6165                      Layer-2-IS-IS                   April 2011

   commonly known as TLVs.  In this document, we specify a set of TLVs
   to be added to [IS-IS] PDUs, to support these proposed systems.  The
   TLVs are generic Layer-2 additions, and specific ones, as needed, are
   defined in the IS-IS technology-specific extensions.  This document
   does not propose any new forwarding mechanisms using this additional
   information carried within IS-IS.

1.1.  Terminology

   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].

2.  TLV Enhancements to IS-IS

   This section specifies the enhancements for the TLVs that are needed