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
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