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Intermediate System to Intermediate System (IS-IS) Extensions in Support of Generalized Multi-Protocol Label Switching (GMPLS)
RFC 4205

Document type: RFC - Informational (October 2005; No errata)
Obsoleted by RFC 5307
Updates RFC 3784
Document stream: IETF
Last updated: 2013-03-02
Other versions: plain text, pdf, html

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

This information refers to IESG processing after the RFC was initially published:
IESG State: RFC 4205 (Informational)
Responsible AD: Ross Callon
Send notices to: isis-chairs@tools.ietf.org

Network Working Group                                   K. Kompella, Ed.
Request for Comments: 4205                               Y. Rekhter, Ed.
Updates: 3784                                           Juniper Networks
Category: Informational                                     October 2005

     Intermediate System to Intermediate System (IS-IS) Extensions
    in Support of Generalized Multi-Protocol Label Switching (GMPLS)

Status of This Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2005).

Abstract

   This document specifies encoding of extensions to the IS-IS routing
   protocol in support of Generalized Multi-Protocol Label Switching
   (GMPLS).

1.  Introduction

   This document specifies extensions to the IS-IS routing protocol in
   support of carrying link state information for Generalized Multi-
   Protocol Label Switching (GMPLS).  The set of required enhancements
   to IS-IS are outlined in [GMPLS-ROUTING].  Support for unnumbered
   interfaces assumes support for the "Point-to-Point Three-Way
   Adjacency" IS-IS Option type [ISIS-3way].

   In this section we define the enhancements to the Traffic Engineering
   (TE) properties of GMPLS TE links that can be announced in IS-IS Link
   State Protocol Data Units.

   In this document, we enhance the sub-TLVs for the extended IS
   reachability TLV (see [ISIS-TE]) in support of GMPLS.  Specifically,
   we add the following sub-TLVs:

      Sub-TLV Type      Length      Name
                 4           8      Link Local/Remote Identifiers
                20           2      Link Protection Type
                21      variable    Interface Switching Capability
                                    Descriptor

Kompella & Rekhter           Informational                      [Page 1]
RFC 4205               IS-IS Extensions for MPLS            October 2005

   We further add one new TLV to the TE TLVs:

          TLV Type      Length    Name
               138      variable  Shared Risk Link Group

   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].

1.1.  Link Local/Remote Identifiers

   A Link Local Interface Identifiers is a sub-TLV of the extended IS
   reachability TLV.  The type of this sub-TLV is 4, and length is eight
   octets.  The value field of this sub-TLV contains four octets of Link
   Local Identifier followed by four octets of Link Remote Identifier
   (see Section "Support for unnumbered links" of [GMPLS-ROUTING]).  If
   the Link Remote Identifier is unknown, it is set to 0.

   The following illustrates encoding of the Value field of the Link
   Local/Remote Identifiers sub-TLV.

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  Link Local Identifier                        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  Link Remote Identifier                       |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The Link Local/Remote Identifiers sub-TLV MUST NOT occur more than
   once within the extended IS reachability TLV.  If the Link
   Local/Remote Identifiers sub-TLV occurs more than once within the
   extended IS reachability TLV, the receiver SHOULD ignore all these
   sub-TLVs.

1.2.  Link Protection Type

   The Link Protection Type is a sub-TLV (of type 20) of the extended IS
   reachability TLV, with length two octets.

   The following illustrates encoding of the Value field of the Link
   Protection Type sub-TLV.

       0                   1
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |Protection Cap |    Reserved   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Kompella & Rekhter           Informational                      [Page 2]
RFC 4205               IS-IS Extensions for MPLS            October 2005

   The first octet is a bit vector describing the protection
   capabilities of the link (see Section "Link Protection Type" of
   [GMPLS-ROUTING]).  They are:

      0x01  Extra Traffic

      0x02  Unprotected

      0x04  Shared

      0x08  Dedicated 1:1

      0x10  Dedicated 1+1

      0x20  Enhanced

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