A Framework for Inter-Domain Multiprotocol Label Switching Traffic Engineering
RFC 4726

Network Working Group                                          A. Farrel
Request for Comments: 4726                            Old Dog Consulting
Category: Informational                                    J.-P. Vasseur
                                                     Cisco Systems, Inc.
                                                             A. Ayyangar
                                                           Nuova Systems
                                                           November 2006

       A Framework for Inter-Domain Multiprotocol Label Switching
                          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 IETF Trust (2006).

Abstract

   This document provides a framework for establishing and controlling
   Multiprotocol Label Switching (MPLS) and Generalized MPLS (GMPLS)
   Traffic Engineered (TE) Label Switched Paths (LSPs) in multi-domain
   networks.

   For the purposes of this document, a domain is considered to be any
   collection of network elements within a common sphere of address
   management or path computational responsibility.  Examples of such
   domains include Interior Gateway Protocol (IGP) areas and Autonomous
   Systems (ASes).

Farrel, et al.               Informational                      [Page 1]
RFC 4726             Framework for Inter-Domain TE         November 2006

Table of Contents

   1. Introduction ....................................................3
      1.1. Nested Domains .............................................3
   2. Signaling Options ...............................................4
      2.1. LSP Nesting ................................................4
      2.2. Contiguous LSP .............................................5
      2.3. LSP Stitching ..............................................5
      2.4. Hybrid Methods .............................................6
      2.5. Control of Downstream Choice of Signaling Method ...........6
   3. Path Computation Techniques .....................................6
      3.1. Management Configuration ...................................7
      3.2. Head-End Computation .......................................7
           3.2.1. Multi-Domain Visibility Computation .................7
           3.2.2. Partial Visibility Computation ......................7
           3.2.3. Local Domain Visibility Computation .................8
      3.3. Domain Boundary Computation ................................8
      3.4. Path Computation Element ...................................9
           3.4.1. Multi-Domain Visibility Computation ................10
           3.4.2. Path Computation Use of PCE When Preserving
                  Confidentiality ....................................10
           3.4.3. Per-Domain Computation Elements ....................10
      3.5. Optimal Path Computation ..................................11
   4. Distributing Reachability and TE Information ...................11
   5. Comments on Advanced Functions .................................12
      5.1. LSP Re-Optimization .......................................12
      5.2. LSP Setup Failure .........................................13
      5.3. LSP Repair ................................................14
      5.4. Fast Reroute ..............................................14
      5.5. Comments on Path Diversity ................................15
      5.6. Domain-Specific Constraints ...............................16
      5.7. Policy Control ............................................17
      5.8. Inter-Domain Operations and Management (OAM) ..............17
      5.9. Point-to-Multipoint .......................................17
      5.10. Applicability to Non-Packet Technologies .................17
   6. Security Considerations ........................................18
   7. Acknowledgements ...............................................19
   8. Normative References ...........................................19
   9. Informative References .........................................20

Farrel, et al.               Informational                      [Page 2]
RFC 4726             Framework for Inter-Domain TE         November 2006

1.  Introduction

   The Traffic Engineering Working Group has developed requirements for
   inter-area and inter-AS Multiprotocol Label Switching (MPLS) Traffic
   Engineering in [RFC4105] and [RFC4216].

   Various proposals have subsequently been made to address some or all
   of these requirements through extensions to the Resource Reservation
   Protocol Traffic Engineering extensions (RSVP-TE) and to the Interior