Requirements for Path Computation Element (PCE) Discovery
RFC 4674

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Network Working Group                                  J.L. Le Roux, Ed.
Request for Comments: 4674                                France Telecom
Category: Informational                                     October 2006

       Requirements for Path Computation Element (PCE) Discovery

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 (2006).

Abstract

   This document presents a set of requirements for a Path Computation
   Element (PCE) discovery mechanism that would allow a Path Computation
   Client (PCC) to discover dynamically and automatically a set of PCEs
   along with certain information relevant for PCE selection.  It is
   intended that solutions that specify procedures and protocols or
   extensions to existing protocols for such PCE discovery satisfy these
   requirements.

Table of Contents

   1. Introduction ....................................................2
      1.1. Conventions Used in This Document ..........................3
      1.2. Terminology ................................................3
   2. Problem Statement and Requirements Overview .....................4
      2.1. Problem Statement ..........................................4
      2.2. Requirements Overview ......................................5
   3. Example of Application Scenario .................................6
   4. Detailed Requirements ...........................................7
      4.1. PCE Information to Be Disclosed ............................7
           4.1.1. General PCE Information (Mandatory Support) .........8
                  4.1.1.1. Discovery of PCE Location ..................8
                  4.1.1.2. Discovery of PCE Domains and
                           Inter-domain Functions .....................8
           4.1.2. Detailed PCE Information (Optional Support) .........9
                  4.1.2.1. Discovery of PCE Capabilities ..............9
                  4.1.2.2. Discovery of Alternate PCEs ...............10
      4.2. Scope of PCE Discovery ....................................10
           4.2.1. Inter-AS Specific Requirements .....................10

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RFC 4674             Requirements for PCE Discovery         October 2006

      4.3. PCE Information Synchronization ...........................11
      4.4. Discovery of PCE Deactivation .............................11
      4.5. Policy Support ............................................12
      4.6. Security Requirements .....................................12
      4.7. Extensibility .............................................13
      4.8. Scalability ...............................................13
      4.9. Operational Orders of Magnitudes ..........................13
      4.10. Manageability Considerations .............................14
           4.10.1. Configuration of PCE Discovery Parameters .........14
           4.10.2. PCE Discovery MIB Modules .........................14
                  4.10.2.1. PCC MIB Module ...........................14
                  4.10.2.2. PCE MIB module ...........................15
           4.10.3. Monitoring Protocol Operations ....................15
           4.10.4. Impact on Network Operations ......................16
   5. Security Considerations ........................................16
   6. Acknowledgements ...............................................16
   7. Contributors ...................................................17
   8. References .....................................................17
      8.1. Normative References ......................................17
      8.2. Informative References ....................................17

1.  Introduction

   The PCE-based network architecture [RFC4655] defines a Path
   Computation Element (PCE) as an entity capable of computing TE-LSP
   paths based on a network graph, and applying computational
   constraints.  A PCE serves path computation requests sent by Path
   Computation Clients (PCC).

   A PCC is a client application requesting a path computation to be
   performed by a PCE.  This can be, for instance, an LSR requesting a
   path for a TE-LSP for which it is the head-end, or a PCE requesting a
   path computation of another PCE (inter-PCE communication).  The
   communication between a PCC and a PCE requires a client-server
   protocol whose generic requirements are listed in [RFC4657].

   The PCE based architecture requires that a PCC be aware of the
   location of one or more PCEs in its domain, and also potentially of
   some PCEs in other domains, e.g., in case of inter-domain path
   computation.

Le Roux                      Informational                      [Page 2]
RFC 4674             Requirements for PCE Discovery         October 2006