Requirements for Inter-Area MPLS Traffic Engineering
RFC 4105

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Network Working Group                                 J.-L. Le Roux, Ed.
Request for Comments: 4105                                France Telecom
Category: Informational                               J.-P. Vasseur, Ed.
                                                     Cisco Systems, Inc.
                                                           J. Boyle, Ed.
                                                                  PDNETs
                                                               June 2005

         Requirements for Inter-Area MPLS Traffic Engineering

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 (2005).

Abstract

   This document lists a detailed set of functional requirements for the
   support of inter-area MPLS Traffic Engineering (inter-area MPLS TE).
   It is intended that solutions that specify procedures and protocol
   extensions for inter-area MPLS TE satisfy these requirements.

Table of Contents

   1. Introduction ....................................................2
   2. Conventions Used in This Document ...............................3
   3. Terminology .....................................................3
   4. Current Intra-Area Uses of MPLS Traffic Engineering .............4
      4.1. Intra-Area MPLS Traffic Engineering Architecture ...........4
      4.2. Intra-Area MPLS Traffic Engineering Applications ...........4
           4.2.1. Intra-Area Resource Optimization ....................4
           4.2.2. Intra-Area QoS Guarantees ...........................5
           4.2.3. Fast Recovery within an IGP Area ....................5
      4.3. Intra-Area MPLS TE and Routing .............................6
   5. Problem Statement, Requirements, and Objectives of Inter-Area ...6
      5.1. Inter-Area Traffic Engineering Problem Statement ...........6
      5.2. Overview of Requirements for Inter-Area MPLS TE ............7
      5.3. Key Objectives for an Inter-Area MPLS-TE Solution ..........8
           5.3.1. Preserving the IGP Hierarchy Concept ................8
           5.3.2. Preserving Scalability ..............................8
   6. Application Scenario.............................................9

Le Roux, et al.              Informational                      [Page 1]
RFC 4105                Inter-Area MPLS TE Reqs                June 2005

   7. Detailed Requirements for Inter-Area MPLS TE ...................10
      7.1. Inter-Area MPLS TE Operations and Interoperability ........10
      7.2. Inter-Area TE-LSP Signaling ...............................10
      7.3. Path Optimality ...........................................11
      7.4. Inter-Area MPLS-TE Routing ................................11
      7.5. Inter-Area MPLS-TE Path Computation .......................12
      7.6. Inter-Area Crankback Routing ..............................12
      7.7. Support of Diversely-Routed Inter-Area TE LSPs ............13
      7.8. Intra/Inter-Area Path Selection Policy ....................13
      7.9. Reoptimization of Inter-Area TE LSP .......................13
      7.10. Inter-Area LSP Recovery ..................................14
            7.10.1. Rerouting of Inter-Area TE LSPs ..................14
            7.10.2. Fast Recovery of Inter-Area TE LSP ...............14
      7.11. DS-TE support ............................................15
      7.12. Hierarchical LSP Support .................................15
      7.13. Hard/Soft Preemption .....................................15
      7.14. Auto-Discovery of TE Meshes ..............................16
      7.15. Inter-Area MPLS TE Fault Management Requirements .........16
      7.16. Inter-Area MPLS TE and Routing ...........................16
   8. Evaluation criteria ............................................17
      8.1. Performances ..............................................17
      8.2. Complexity and Risks ......................................17
      8.3. Backward Compatibility ....................................17
   9. Security Considerations ........................................17
   10. Acknowledgements ..............................................17
   11. Contributing Authors ..........................................18
   12. Normative References ..........................................19
   13. Informative References ........................................19

1.  Introduction

   The set of MPLS Traffic Engineering components, defined in [RSVP-TE],
   [OSPF-TE], and [ISIS-TE], which supports the requirements defined in
   [TE-REQ], is used today by many network operators to achieve major
   Traffic Engineering objectives defined in [TE-OVW].  These objectives
   include:

      - Aggregated Traffic measurement
      - Optimization of network resources utilization
      - Support for services requiring end-to-end QoS guarantees