IS-IS Extensions for Traffic Engineering
RFC 5305

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Network Working Group                                              T. Li
Request for Comments: 5305                        Redback Networks, Inc.
Obsoletes: 3784                                                  H. Smit
Category: Standards Track                                   October 2008

                IS-IS Extensions for Traffic Engineering

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 describes extensions to the Intermediate System to
   Intermediate System (IS-IS) protocol to support Traffic Engineering
   (TE).  This document extends the IS-IS protocol by specifying new
   information that an Intermediate System (router) can place in Link
   State Protocol Data Units (LSP).  This information describes
   additional details regarding the state of the network that are useful
   for traffic engineering computations.

Li & Smit                   Standards Track                     [Page 1]
RFC 5305        IS-IS Extensions for Traffic Engineering    October 2008

Table of Contents

   1. Introduction ....................................................2
      1.1. Requirements Language ......................................3
   2. Introducing Sub-TLVs ............................................3
   3. The Extended IS Reachability TLV ................................3
      3.1. Sub-TLV 3: Administrative Group (color, resource class) ....6
      3.2. Sub-TLV 6: IPv4 Interface Address ..........................6
      3.3. Sub-TLV 8: IPv4 Neighbor Address ...........................6
      3.4. Sub-TLV 9: Maximum Link Bandwidth ..........................7
      3.5. Sub-TLV 10: Maximum Reservable Link Bandwidth ..............7
      3.6. Sub-TLV 11: Unreserved Bandwidth ...........................7
      3.7. Sub-TLV 18: Traffic Engineering Default Metric .............8
   4. The Extended IP Reachability TLV ................................8
      4.1. The up/down Bit ...........................................10
      4.2. Expandability of the Extended IP Reachability TLV
           with Sub-TLVs .............................................11
      4.3. The Traffic Engineering Router ID TLV .....................11
   5. IANA Considerations ............................................12
      5.1. TLV Codepoint Allocations .................................12
      5.2. New Registries ............................................13
           5.2.1. Sub-TLVs for the Extended IS Reachability TLV ......13
           5.2.2. Sub-TLVs for the Extended IP Reachability TLV ......15
   6. Security Considerations ........................................15
   7. Acknowledgements ...............................................15
   8. References .....................................................15
      8.1. Normative References ......................................15
      8.2. Informative References ....................................15

1.  Introduction

   The IS-IS protocol is specified in ISO 10589 [ISO-10589], with
   extensions for supporting IPv4 specified in [RFC1195].  Each
   Intermediate System (IS) (router) advertises one or more IS-IS Link
   State Protocol Data Units (LSPs) with routing information.  Each 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 commonly known as
   TLVs, and are a good way of encoding information in a flexible and
   extensible format.

   This document contains the design of new TLVs to replace the existing
   IS Neighbor TLV and IP Reachability TLV, and to include additional
   information about the characteristics of a particular link to an IS-
   IS LSP.  The characteristics described in this document are needed
   for traffic engineering [RFC2702].  Secondary goals include
   increasing the dynamic range of the IS-IS metric and improving the
   encoding of IP prefixes.

Li & Smit                   Standards Track                     [Page 2]
RFC 5305        IS-IS Extensions for Traffic Engineering    October 2008

   The router ID is useful for traffic engineering purposes because it
   describes a single address that can always be used to reference a
   particular router.

   Mechanisms and procedures to migrate to the new TLVs are not
   discussed in this document.

   A prior version of this document was published as [RFC3784] with
   Informational status.  This version is on the standards track.

1.1.  Requirements Language

   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].