Extensions to the Path Computation Element Communication Protocol (PCEP) for Route Exclusions
RFC 5521

Network Working Group                                             E. Oki
Request for Comments: 5521          University of Electro-Communications
Category: Standards Track                                      T. Takeda
                                                                     NTT
                                                               A. Farrel
                                                      Old Dog Consulting
                                                              April 2009

   Extensions to the Path Computation Element Communication Protocol
                      (PCEP) for Route Exclusions

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.

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Oki, et al.                 Standards Track                     [Page 1]
RFC 5521        Extensions to PCEP for Route Exclusions       April 2009

Abstract

   The Path Computation Element (PCE) provides functions of path
   computation in support of traffic engineering (TE) in Multi-Protocol
   Label Switching (MPLS) and Generalized MPLS (GMPLS) networks.

   When a Path Computation Client (PCC) requests a PCE for a route, it
   may be useful for the PCC to specify, as constraints to the path
   computation, abstract nodes, resources, and Shared Risk Link Groups
   (SRLGs) that are to be explicitly excluded from the computed route.
   Such constraints are termed "route exclusions".

   The PCE Communication Protocol (PCEP) is designed as a communication
   protocol between PCCs and PCEs.  This document presents PCEP
   extensions for route exclusions.

Table of Contents

   1.  Introduction ................................................. 3
       1.1.  Conventions Used in This Document .......................3
   2.  Protocol Procedures and Extensions ........................... 4
       2.1.  Exclude Route Object (XRO) ............................. 4
             2.1.1.  Definition ..................................... 4
             2.1.2.  Processing Rules ............................... 8
       2.2.  Explicit Route Exclusion ............................... 9
             2.2.1.  Definition ..................................... 9
             2.2.2.  Processing Rules .............................. 10
   3.  Exclude Route with Confidentiality .......................... 11
       3.1.  Exclude Route Object (XRO) Carrying Path-Key .......... 11
             3.1.1.  Definition .................................... 11
             3.1.2.  Processing Rules .............................. 12
   4.  IANA Considerations ......................................... 13
       4.1.  PCEP Objects .......................................... 13
       4.2.  New Subobject for the Include Route Object ............ 13
       4.3.  Error Object Field Values ............................. 13
       4.4.  Exclude Route Flags ................................... 14
   5.  Manageability Considerations ................................ 14
   6.  Security Considerations ..................................... 14
   7.  References .................................................. 15
       7.1.  Normative References .................................. 15
       7.2.  Informative References ................................ 15
   Acknowledgements ................................................ 16

Oki, et al.                 Standards Track                     [Page 2]