Applicability Statement for Traffic Engineering with MPLS
RFC 3346

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Network Working Group                                           J. Boyle
Request for Comments: 3346                                       PD Nets
Category: Informational                                          V. Gill
                                                   AOL Time Warner, Inc.
                                                               A. Hannan
                                                             RoutingLoop
                                                               D. Cooper
                                                         Global Crossing
                                                              D. Awduche
                                                          Movaz Networks
                                                            B. Christian
                                                                Worldcom
                                                                W.S. Lai
                                                                    AT&T
                                                             August 2002

       Applicability Statement for Traffic Engineering with MPLS

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2002).  All Rights Reserved.

Abstract

   This document describes the applicability of Multiprotocol Label
   Switching (MPLS) to traffic engineering in IP networks.  Special
   considerations for deployment of MPLS for traffic engineering in
   operational contexts are discussed and the limitations of the MPLS
   approach to traffic engineering are highlighted.

Boyle, et al.                Informational                      [Page 1]
RFC 3346    Applicability Statement for Traffic Engineering  August 2002

Table of Contents

   1.  Introduction....................................................2
   2.  Technical Overview of ISP Traffic Engineering...................3
   3.  Applicability of Internet Traffic Engineering...................4
   3.1 Avoidance of Congested Resources................................4
   3.2 Resource Utilization in Network Topologies with Parallel Links..5
   3.3 Implementing Routing Policies using Affinities..................5
   3.4 Re-optimization After Restoration...............................6
   4.  Implementation Considerations...................................6
   4.1 Architectural and Operational Considerations....................6
   4.2 Network Management Aspects......................................7
   4.3 Capacity Engineering Aspects....................................8
   4.4 Network Measurement Aspects.....................................8
   5.  Limitations.....................................................9
   6.  Conclusion.....................................................11
   7.  Security Considerations........................................11
   8.  References.....................................................11
   9.  Acknowledgments................................................12
   10. Authors' Addresses.............................................13
   11. Full Copyright Statement.......................................14

1. Introduction

   It is generally acknowledged that one of the most significant initial
   applications of Multiprotocol Label Switching (MPLS) is traffic
   engineering (TE) [1][2] in IP networks.  A significant community of
   IP service providers have found that traffic engineering of their
   networks can have tactical and strategic value [2, 3, 4].  To support
   the traffic engineering application, extensions have been specified
   for Interior Gateway Protocols (IGP) IS-IS [5] and OSPF [6], and to
   signaling protocols RSVP [7] and LDP [8].  The extensions for IS-IS,
   OSPF, and RSVP have all been developed and deployed in large scale in
   many networks consisting of multi-vendor equipment.

   This document discusses the applicability of TE to Internet service
   provider networks, focusing on the MPLS-based approach.  It augments
   the existing protocol applicability statements and, in particular,
   relates to the operational applicability of RSVP-TE [9].  Special
   considerations for deployment of MPLS in operational contexts are
   discussed and the limitations of this approach to traffic engineering
   are highlighted.

Boyle, et al.                Informational                      [Page 2]
RFC 3346    Applicability Statement for Traffic Engineering  August 2002

2. Technical Overview of ISP Traffic Engineering

   Traffic engineering (TE) is generally concerned with the performance
   optimization of operational networks [2].  In contemporary practice,
   TE means mapping IP traffic flows onto the existing physical network
   topology in the most effective way to accomplish desired operational