IS-IS Extensions in Support of Generalized Multi-Protocol Label Switching (GMPLS)
RFC 5307

• Status
• IESG evaluation record
• IESG writeups
• Email expansions
• History

• Versions
• 00

Network Working Group                                   K. Kompella, Ed.
Request for Comments: 5307                               Y. Rekhter, Ed.
Obsoletes: 4205                                         Juniper Networks
Updates: 5305                                               October 2008
Category: Standards Track

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

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.

Abstract

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

Kompella & Rekhter          Standards Track                     [Page 1]
RFC 5307               IS-IS Extensions for GMPLS           October 2008

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

   We further add one new TLV to the TE TLVs:

          TLV Type        Length    Name
               138      variable    GMPLS-SRLG

   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 Identifier is a sub-TLV of the extended IS
   reachability TLV.  The type of this sub-TLV is 4, and the length is 8
   octets.  The value field of this sub-TLV contains 4 octets of Link
   Local Identifier followed by 4 octets of Link Remote Identifier (see
   Section 2.1, "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.

Kompella & Rekhter          Standards Track                     [Page 2]
RFC 5307               IS-IS Extensions for GMPLS           October 2008

       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 a length of 2 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   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

The first octet is a bit vector describing the protection capabilities
   of the link (see Section 2.2, "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

      0x40  Reserved

      0x80  Reserved

Kompella & Rekhter          Standards Track                     [Page 3]
RFC 5307               IS-IS Extensions for GMPLS           October 2008

   The second octet SHOULD be set to zero by the sender, and SHOULD be