Applicability of a Stateful Path Computation Element (PCE)
RFC 8051
Internet Engineering Task Force (IETF) X. Zhang, Ed.
Request for Comments: 8051 Huawei Technologies
Category: Informational I. Minei, Ed.
ISSN: 2070-1721 Google, Inc.
January 2017
Applicability of a Stateful Path Computation Element (PCE)
Abstract
A stateful Path Computation Element (PCE) maintains information about
Label Switched Path (LSP) characteristics and resource usage within a
network in order to provide traffic-engineering calculations for its
associated Path Computation Clients (PCCs). This document describes
general considerations for a stateful PCE deployment and examines its
applicability and benefits, as well as its challenges and
limitations, through a number of use cases. PCE Communication
Protocol (PCEP) extensions required for stateful PCE usage are
covered in separate documents.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
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). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see 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
http://www.rfc-editor.org/info/rfc8051.
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RFC 8051 Applicability for a Stateful PCE January 2017
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Application Scenarios . . . . . . . . . . . . . . . . . . . . 5
3.1. Optimization of LSP Placement . . . . . . . . . . . . . . 5
3.1.1. Throughput Maximization and Bin Packing . . . . . . . 6
3.1.2. Deadlock . . . . . . . . . . . . . . . . . . . . . . 7
3.1.3. Minimum Perturbation . . . . . . . . . . . . . . . . 9
3.1.4. Predictability . . . . . . . . . . . . . . . . . . . 10
3.2. Auto-Bandwidth Adjustment . . . . . . . . . . . . . . . . 11
3.3. Bandwidth Scheduling . . . . . . . . . . . . . . . . . . 12
3.4. Recovery . . . . . . . . . . . . . . . . . . . . . . . . 12
3.4.1. Protection . . . . . . . . . . . . . . . . . . . . . 13
3.4.2. Restoration . . . . . . . . . . . . . . . . . . . . . 14
3.4.3. SRLG Diversity . . . . . . . . . . . . . . . . . . . 15
3.5. Maintenance of Virtual Network Topology (VNT) . . . . . . 15
3.6. LSP Reoptimization . . . . . . . . . . . . . . . . . . . 16
3.7. Resource Defragmentation . . . . . . . . . . . . . . . . 17
3.8. Point-to-Multipoint Applications . . . . . . . . . . . . 17
3.9. Impairment-Aware Routing and Wavelength Assignment
(IA-RWA) . . . . . . . . . . . . . . . . . . . . . . . . 18
4. Deployment Considerations . . . . . . . . . . . . . . . . . . 19
4.1. Multi-PCE Deployments . . . . . . . . . . . . . . . . . . 19
4.2. LSP State Synchronization . . . . . . . . . . . . . . . . 19
4.3. PCE Survivability . . . . . . . . . . . . . . . . . . . . 19
5. Security Considerations . . . . . . . . . . . . . . . . . . . 20
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.1. Normative References . . . . . . . . . . . . . . . . . . 20
6.2. Informative References . . . . . . . . . . . . . . . . . 21
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 22
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 24
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