IGP Routing Protocol Extensions for Discovery of Traffic Engineering Node Capabilities
RFC 5073

Network Working Group                                  J.P. Vasseur, Ed.
Request for Comments: 5073                           Cisco Systems, Inc.
Category: Standards Track                              J.L. Le Roux, Ed.
                                                          France Telecom
                                                           December 2007

                  IGP Routing Protocol Extensions for
           Discovery of Traffic Engineering Node Capabilities

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

   It is highly desired, in several cases, to take into account Traffic
   Engineering (TE) node capabilities during Multi Protocol Label
   Switching (MPLS) and Generalized MPLS (GMPLS) Traffic Engineered
   Label Switched Path (TE-LSP) selection, such as, for instance, the
   capability to act as a branch Label Switching Router (LSR) of a
   Point-To-MultiPoint (P2MP) LSP.  This requires advertising these
   capabilities within the Interior Gateway Protocol (IGP).  For that
   purpose, this document specifies Open Shortest Path First (OSPF) and
   Intermediate System-Intermediate System (IS-IS) traffic engineering
   extensions for the advertisement of control plane and data plane
   traffic engineering node capabilities.

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RFC 5073         IGP Ext for Discovery of TE Node Cap      December 2007

Table of Contents

   1. Introduction.....................................................2
   2. Terminology......................................................3
   3. TE Node Capability Descriptor ...................................3
      3.1. Description ................................................3
      3.2. Required Information .......................................3
   4. TE Node Capability Descriptor TLV Formats .......................4
      4.1. OSPF TE Node Capability Descriptor TLV Format ..............4
      4.2. IS-IS TE Node Capability Descriptor sub-TLV format .........5
   5. Elements of Procedure ...........................................6
      5.1. OSPF .......................................................6
      5.2. IS-IS ......................................................7
   6. Backward Compatibility ..........................................8
   7. Security Considerations .........................................8
   8. IANA Considerations .............................................8
      8.1. OSPF TLV ...................................................8
      8.2. ISIS sub-TLV ...............................................8
      8.3. Capability Registry ........................................9
   9. Acknowledgments .................................................9
   10. References ....................................................10
      10.1. Normative References .....................................10
      10.2. Informative References ...................................11

1.  Introduction

   Multi Protocol Label Switching-Traffic Engineering (MPLS-TE) routing
   ([RFC3784], [RFC3630], [OSPFv3-TE]) relies on extensions to link
   state Interior Gateway Protocols (IGP) ([IS-IS], [RFC1195],
   [RFC2328], [RFC2740]) in order to advertise Traffic Engineering (TE)
   link information used for constraint-based routing.  Further
   Generalized MPLS (GMPLS) related routing extensions are defined in
   [RFC4205] and [RFC4203].

   It is desired to complement these routing extensions in order to
   advertise TE node capabilities, in addition to TE link information.
   These TE node capabilities will be taken into account as constraints
   during path selection.

   Indeed, it is useful to advertise data plane TE node capabilities,
   such as the capability for a Label Switching Router (LSR) to be a
   branch LSR or a bud-LSR of a Point-To-MultiPoint (P2MP) Label
   Switched Path (LSP).  These capabilities can then be taken into
   account as constraints when computing the route of TE LSPs.

   It is also useful to advertise control plane TE node capabilities
   such as the capability to support GMPLS signaling for a packet LSR,
   or the capability to support P2MP (Point to Multipoint) TE LSP

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RFC 5073         IGP Ext for Discovery of TE Node Cap      December 2007

   signaling.  This allows selecting a path that avoids nodes that do
   not support a given control plane feature, or triggering a mechanism