Path Computation Element (PCE) Communication Protocol Generic Requirements
RFC 4657
Network Working Group J. Ash, Ed.
Request for Comments: 4657 AT&T
Category: Informational J.L. Le Roux, Ed.
France Telecom
September 2006
Path Computation Element (PCE) Communication Protocol
Generic Requirements
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
The PCE model is described in the "PCE Architecture" document and
facilitates path computation requests from Path Computation Clients
(PCCs) to Path Computation Elements (PCEs). This document specifies
generic requirements for a communication protocol between PCCs and
PCEs, and also between PCEs where cooperation between PCEs is
desirable. Subsequent documents will specify application-specific
requirements for the PCE communication protocol.
Table of Contents
1. Introduction ....................................................2
2. Conventions Used in This Document ...............................3
3. Terminology .....................................................3
4. Overview of PCE Communication Protocol (PCECP) ..................4
5. PCE Communication Protocol Generic Requirements .................5
5.1. Basic Protocol Requirements ................................5
5.1.1. Commonality of PCC-PCE and PCE-PCE Communication ....5
5.1.2. Client-Server Communication .........................5
5.1.3. Transport ...........................................5
5.1.4. Path Computation Requests ...........................5
5.1.5. Path Computation Responses ..........................7
5.1.6. Cancellation of Pending Requests ....................7
5.1.7. Multiple Requests and Responses .....................8
5.1.8. Reliable Message Exchange ...........................8
5.1.9. Secure Message Exchange .............................9
Ash & Le Roux Informational [Page 1]
RFC 4657 PCE Communication Protocol Generic Reqmnts September 2006
5.1.10. Request Prioritization ............................10
5.1.11. Unsolicited Notifications .........................10
5.1.12. Asynchronous Communication ........................10
5.1.13. Communication Overhead Minimization ...............10
5.1.14. Extensibility .....................................11
5.1.15. Scalability .......................................11
5.1.16. Constraints .......................................12
5.1.17. Objective Functions Supported .....................13
5.2. Deployment Support Requirements ...........................13
5.2.1. Support for Different Service Provider
Environments .......................................13
5.2.2. Policy Support .....................................14
5.3. Aliveness Detection & Recovery Requirements ...............14
5.3.1. Aliveness Detection ................................14
5.3.2. Protocol Recovery ..................................14
5.3.3. LSP Rerouting & Reoptimization .....................14
6. Security Considerations ........................................15
7. Manageability Considerations ...................................16
8. Contributors ...................................................17
9. Acknowledgements ...............................................18
10. References ....................................................19
10.1. Normative References .....................................19
10.2. Informative References ...................................19
1. Introduction
A Path Computation Element (PCE) [RFC4655] supports requests for path
computation issued by a Path Computation Client (PCC), which may be
'composite' (co-located) or 'external' (remote) from a PCE. When the
PCC is external from the PCE, a request/response communication
protocol is required to carry the path computation request and return
the response. In order for the PCC and PCE to communicate, the PCC
must know the location of the PCE; PCE discovery is described in
[PCE-DISC-REQ].
The PCE operates on a network graph in order to compute paths based
on the path computation request(s) issued by the PCC(s). The path
computation request will include the source and destination of the
paths to be computed and a set of constraints to be applied during
the computation, and it may also include an objective function. The
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