Optimizations of Label Switched Path State Synchronization Procedures for a Stateful PCE
RFC 8232
Internet Engineering Task Force (IETF) E. Crabbe
Request for Comments: 8232 Oracle
Category: Standards Track I. Minei
ISSN: 2070-1721 Google, Inc.
J. Medved
Cisco Systems, Inc.
R. Varga
Pantheon Technologies SRO
X. Zhang
D. Dhody
Huawei Technologies
September 2017
Optimizations of Label Switched Path State Synchronization
Procedures for a Stateful PCE
Abstract
A stateful Path Computation Element (PCE) has access to not only the
information disseminated by the network's Interior Gateway Protocol
(IGP) but also the set of active paths and their reserved resources
for its computation. The additional Label Switched Path (LSP) state
information allows the PCE to compute constrained paths while
considering individual LSPs and their interactions. This requires a
State Synchronization mechanism between the PCE and the network, the
PCE and Path Computation Clients (PCCs), and cooperating PCEs. The
basic mechanism for State Synchronization is part of the stateful PCE
specification. This document presents motivations for optimizations
to the base State Synchronization procedure and specifies the
required Path Computation Element Communication Protocol (PCEP)
extensions.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8232.
Crabbe, et al. Standards Track [Page 1]
RFC 8232 Optimizations of State Synchronization September 2017
Copyright Notice
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Crabbe, et al. Standards Track [Page 2]
RFC 8232 Optimizations of State Synchronization September 2017
Table of Contents
1. Introduction ....................................................4
1.1. Requirements Language ......................................4
2. Terminology .....................................................5
3. State Synchronization Avoidance .................................5
3.1. Motivation .................................................5
3.2. State Synchronization Avoidance Procedure ..................5
3.2.1. IP Address Change during Session Re-establishment ..10
3.3. PCEP Extensions ...........................................11
3.3.1. LSP-DB Version Number TLV ..........................11
3.3.2. Speaker Entity Identifier TLV ......................12
4. Incremental State Synchronization ..............................13
4.1. Motivation ................................................13
4.2. Incremental Synchronization Procedure .....................14
5. PCE-Triggered Initial Synchronization ..........................17
5.1. Motivation ................................................17
5.2. PCE-Triggered Initial State Synchronization Procedure .....18
6. PCE-Triggered Resynchronization ................................19
6.1. Motivation ................................................19
6.2. PCE-Triggered State Resynchronization Procedure ...........19
7. Advertising Support of Synchronization Optimizations ...........20
8. IANA Considerations ............................................21
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