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Intermediate System to Intermediate System (IS-IS) Extensions for Advertising Router Information
RFC 4971

Document type: RFC - Proposed Standard (July 2007; No errata)
Document stream: IETF
Last updated: 2013-03-02
Other versions: plain text, pdf, html

IETF State: (None)
Consensus: Unknown
Document shepherd: No shepherd assigned

IESG State: RFC 4971 (Proposed Standard)
Responsible AD: Bill Fenner
Send notices to: isis-chairs@tools.ietf.org

Network Working Group                                   JP. Vasseur, Ed.
Request for Comments: 4971                                  N. Shen, Ed.
Category: Standards Track                            Cisco Systems, Inc.
                                                        R. Aggarwal, Ed.
                                                        Juniper Networks
                                                               July 2007

     Intermediate System to Intermediate System (IS-IS) Extensions
                  for Advertising Router Information

Status of This Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The IETF Trust (2007).

Abstract

   This document defines a new optional Intermediate System to
   Intermediate System (IS-IS) TLV named CAPABILITY, formed of multiple
   sub-TLVs, which allows a router to announce its capabilities within
   an IS-IS level or the entire routing domain.

Table of Contents

   1. Introduction ....................................................2
      1.1. Conventions Used in This Document ..........................2
   2. IS-IS Router CAPABILITY TLV .....................................3
   3. Elements of Procedure ...........................................4
   4. Interoperability with Routers Not Supporting the
      Capability TLV ..................................................5
   5. Security Considerations .........................................6
   6. IANA Considerations .............................................6
   7. Acknowledgment ..................................................6
   8. References ......................................................6
      8.1. Normative References .......................................6
      8.2. Informative References .....................................8

Vasseur, et al.             Standards Track                     [Page 1]
RFC 4971      IS-IS Extensions for Advertising Router Info     July 2007

1.  Introduction

   There are several situations where it is useful for the IS-IS [IS-IS]
   [IS-IS-IP] routers to learn the capabilities of the other routers of
   their IS-IS level, area, or routing domain.  For the sake of
   illustration, three examples related to MPLS Traffic Engineering (TE)
   are described here:

   1. Mesh-group: the setting up of a mesh of TE Label Switched Paths
      (LSPs) [IS-IS-TE] requires some significant configuration effort.
      [AUTOMESH] proposes an auto-discovery mechanism whereby every
      Label Switching Router (LSR) of a mesh advertises its mesh-group
      membership by means of IS-IS extensions.

   2. Point to Multipoint TE LSP (P2MP LSP).  A specific sub-TLV
      ([TE-NODE-CAP]) allows an LSR to advertise its Point To Multipoint
      capabilities ([P2MP] and [P2MP-REQS]).

   3. Inter-area traffic engineering: Advertisement of the IPv4 and/or
      the IPv6 Traffic Engineering Router IDs.

   The use of IS-IS for Path Computation Element (PCE) discovery may
   also be considered and will be discussed in the PCE WG.

   The capabilities mentioned above require the specification of new
   sub-TLVs carried within the CAPABILITY TLV defined in this document.

   Note that the examples above are provided for the sake of
   illustration.  This document proposes a generic capability
   advertising mechanism that is not limited to MPLS Traffic
   Engineering.

   This document defines a new optional IS-IS TLV named CAPABILITY,
   formed of multiple sub-TLVs, which allows a router to announce its
   capabilities within an IS-IS level or the entire routing domain.  The
   applications mentioned above require the specification of new sub-
   TLVs carried within the CAPABILITY TLV defined in this document.

   Definition of these sub-TLVs is outside the scope of this document.

1.1.  Conventions Used in This Document

   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 [RFC-2119].

Vasseur, et al.             Standards Track                     [Page 2]
RFC 4971      IS-IS Extensions for Advertising Router Info     July 2007

2.  IS-IS Router CAPABILITY TLV

   The IS-IS Router CAPABILITY TLV is composed of 1 octet for the type,

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