Generalized Multi-Protocol Label Switching (GMPLS) Recovery Functional Specification
RFC 4426
Network Working Group J. Lang, Ed.
Request for Comments: 4426 B. Rajagopalan, Ed.
Category: Standards Track D. Papadimitriou, Ed.
March 2006
Generalized Multi-Protocol Label Switching (GMPLS)
Recovery Functional Specification
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.
Copyright Notice
Copyright (C) The Internet Society (2006).
Abstract
This document presents a functional description of the protocol
extensions needed to support Generalized Multi-Protocol Label
Switching (GMPLS)-based recovery (i.e., protection and restoration).
Protocol specific formats and mechanisms will be described in
companion documents.
Table of Contents
1. Introduction ................................................. 2
1.1. Conventions Used in This Document ...................... 3
2. Span Protection .............................................. 3
2.1. Unidirectional 1+1 Dedicated Protection ................ 4
2.2. Bi-directional 1+1 Dedicated Protection ................ 5
2.3. Dedicated 1:1 Protection with Extra Traffic ............ 6
2.4. Shared M:N Protection .................................. 8
2.5. Messages ............................................... 10
2.5.1. Failure Indication Message ..................... 10
2.5.2. Switchover Request Message ..................... 11
2.5.3. Switchover Response Message .................... 11
2.6. Preventing Unintended Connections ...................... 12
3. End-to-End (Path) Protection and Restoration ................. 12
3.1. Unidirectional 1+1 Protection .......................... 12
3.2. Bi-directional 1+1 Protection .......................... 12
3.2.1. Identifiers .................................... 13
3.2.2. Nodal Information .............................. 14
Lang, et al. Standards Track [Page 1]
RFC 4426 GMPLS Recovery Functional Specification March 2006
3.2.3. End-to-End Failure Indication Message .......... 14
3.2.4. End-to-End Failure Acknowledgement Message ..... 15
3.2.5. End-to-End Switchover Request Message .......... 15
3.2.6. End-to-End Switchover Response Message ......... 15
3.3. Shared Mesh Restoration ................................ 15
3.3.1. End-to-End Failure Indication and
Acknowledgement Message ........................ 16
3.3.2. End-to-End Switchover Request Message .......... 16
3.3.3. End-to-End Switchover Response Message ......... 17
4. Reversion and Other Administrative Procedures ................ 17
5. Discussion ................................................... 18
5.1. LSP Priorities During Protection ....................... 18
6. Security Considerations ...................................... 19
7. Contributors ................................................. 20
8. References ................................................... 21
8.1. Normative References ................................... 21
8.2. Informative References ................................. 22
1. Introduction
A requirement for the development of a common control plane for both
optical and electronic switching equipment is that there must be
signaling, routing, and link management mechanisms that support data
plane fault recovery. In this document, the term "recovery" is
generically used to denote both protection and restoration; the
specific terms "protection" and "restoration" are used only when
differentiation is required. The subtle distinction between
protection and restoration is made based on the resource allocation
done during the recovery period (see [RFC4427]).
A label-switched path (LSP) may be subject to local (span), segment,
and/or end-to-end recovery. Local span protection refers to the
protection of the link (and hence all the LSPs marked as required for
span protection and routed over the link) between two neighboring
switches. Segment protection refers to the recovery of an LSP
segment (i.e., an SNC in the ITU-T terminology) between two nodes,
i.e., the boundary nodes of the segment. End-to-end protection
refers to the protection of an entire LSP from the ingress to the
egress port. The end-to-end recovery models discussed in this
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