OSPF-xTE: Experimental Extension to OSPF for Traffic Engineering
RFC 4973

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• 07

Network Working Group                                       P. Srisuresh
Request for Comments: 4973                                Kazeon Systems
Category: Experimental                                         P. Joseph
                                                              Consultant
                                                               July 2007

    OSPF-xTE: Experimental Extension to OSPF for Traffic Engineering

Status of This Memo

   This memo defines an Experimental Protocol for the Internet
   community.  It does not specify an Internet standard of any kind.
   Discussion and suggestions for improvement are requested.
   Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The IETF Trust (2007).

Abstract

   This document defines OSPF-xTE, an experimental traffic engineering
   (TE) extension to the link-state routing protocol OSPF.  OSPF-xTE
   defines new TE Link State Advertisements (LSAs) to disseminate TE
   metrics within an autonomous System (AS), which may consist of
   multiple areas.  When an AS consists of TE and non-TE nodes, OSPF-xTE
   ensures that non-TE nodes in the AS are unaffected by the TE LSAs.
   OSPF-xTE generates a stand-alone TE Link State Database (TE-LSDB),
   distinct from the native OSPF LSDB, for computation of TE circuit
   paths.  OSPF-xTE is versatile and extendible to non-packet networks
   such as Synchronous Optical Network (SONET) / Time Division
   Multiplexing (TDM) and optical networks.

IESG Note

   The content of this RFC was at one time considered by the IETF, and
   therefore it may resemble a current IETF work in progress or a
   published IETF work.  This RFC is not a candidate for any level of
   Internet Standard.  The IETF disclaims any knowledge of the fitness
   of this RFC for any purpose and in particular notes that the decision
   to publish is not based on IETF review for such things as security,
   congestion control, or inappropriate interaction with deployed
   protocols.  The RFC Editor has chosen to publish this document at its
   discretion.  Readers of this RFC should exercise caution in
   evaluating its value for implementation and deployment.  See RFC 3932
   for more information.

Srisuresh & Joseph            Experimental                      [Page 1]
RFC 4973           OSPF Traffic Engineering Extension          July 2007

   See RFC 3630 for the IETF consensus protocol for OSPF Traffic
   Engineering.  The OSPF WG position at the time of publication is that
   although this proposal has some useful properties, the protocol in
   RFC 3630 is sufficient for the traffic engineering needs that have
   been identified so far, and the cost of migrating to this proposal
   exceeds its benefits.

Table of Contents

   1. Introduction ....................................................3
   2. Principles of Traffic Engineering ...............................3
   3. Terminology .....................................................5
      3.1. Native OSPF Terms ..........................................5
      3.2. OSPF-xTE Terms .............................................6
   4. Motivations behind the Design of OSPF-xTE .......................9
      4.1. Scalable Design ............................................9
      4.2. Operable in Mixed and Peer Networks ........................9
      4.3. Efficient in Flooding Reach ................................9
      4.4. Ability to Reserve TE-Exclusive Links .....................10
      4.5. Extensible Design .........................................11
      4.6. Unified for Packet and Non-Packet Networks ................11
      4.7. Networks Benefiting from the OSPF-xTE Design ..............11
   5. OSPF-xTE Solution Overview .....................................12
      5.1. OSPF-xTE Solution .........................................12
      5.2. Assumptions ...............................................13
   6. Strategy for Transition of Opaque LSAs to OSPF-xTE .............14
   7. OSPF-xTE Router Adjacency -- TE Topology Discovery .............14
      7.1. The OSPF-xTE Router Adjacency .............................14
      7.2. The Hello Protocol ........................................15
      7.3. The Designated Router .....................................15
      7.4. The Backup Designated Router ..............................15
      7.5. Flooding and the Synchronization of Databases .............16
      7.6. The Graph of Adjacencies ..................................16
   8. TE LSAs for Packet Network .....................................18
      8.1. TE-Router LSA (0x81) ......................................18
           8.1.1. Router-TE Flags: TE Capabilities of the Router .....19
           8.1.2. Router-TE TLVs .....................................20
           8.1.3. Link-TE Flags: TE Capabilities of a Link ...........22
           8.1.4. Link-TE TLVs .......................................23
      8.2. TE-Incremental-Link-Update LSA (0x8d) .....................26