MPLS Transport Profile (MPLS-TP) Survivability Framework
RFC 6372

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Internet Engineering Task Force (IETF)                  N. Sprecher, Ed.
Request for Comments: 6372                        Nokia Siemens Networks
Category: Informational                                   A. Farrel, Ed.
ISSN: 2070-1721                                         Juniper Networks
                                                          September 2011

        MPLS Transport Profile (MPLS-TP) Survivability Framework

Abstract

   Network survivability is the ability of a network to recover traffic
   delivery following failure or degradation of network resources.
   Survivability is critical for the delivery of guaranteed network
   services, such as those subject to strict Service Level Agreements
   (SLAs) that place maximum bounds on the length of time that services
   may be degraded or unavailable.

   The Transport Profile of Multiprotocol Label Switching (MPLS-TP) is a
   packet-based transport technology based on the MPLS data plane that
   reuses many aspects of the MPLS management and control planes.

   This document comprises a framework for the provision of
   survivability in an MPLS-TP network; it describes recovery elements,
   types, methods, and topological considerations.  To enable data-plane
   recovery, survivability may be supported by the control plane,
   management plane, and by Operations, Administration, and Maintenance
   (OAM) functions.  This document describes mechanisms for recovering
   MPLS-TP Label Switched Paths (LSPs).  A detailed description of
   pseudowire recovery in MPLS-TP networks is beyond the scope of this
   document.

   This document is a product of a joint Internet Engineering Task Force
   (IETF) / International Telecommunication Union Telecommunication
   Standardization Sector (ITU-T) effort to include an MPLS Transport
   Profile within the IETF MPLS and Pseudowire Emulation Edge-to-Edge
   (PWE3) architectures to support the capabilities and functionalities
   of a packet-based transport network as defined by the ITU-T.

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

Sprecher & Farrel             Informational                     [Page 1]
RFC 6372             MPLS-TP Survivability Framework      September 2011

   approved by the IESG are a candidate for any level of Internet
   Standard; see Section 2 of RFC 5741.

   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/rfc6372.

Copyright Notice

   Copyright (c) 2011 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1. Introduction ....................................................4
      1.1. Recovery Schemes ...........................................4
      1.2. Recovery Action Initiation .................................5
      1.3. Recovery Context ...........................................6
      1.4. Scope of This Framework ....................................7
   2. Terminology and References ......................................8
   3. Requirements for Survivability .................................10
   4. Functional Architecture ........................................10
      4.1. Elements of Control .......................................10
           4.1.1. Operator Control ...................................11
           4.1.2. Defect-Triggered Actions ...........................12
           4.1.3. OAM Signaling ......................................12
           4.1.4. Control-Plane Signaling ............................12
      4.2. Recovery Scope ............................................13
           4.2.1. Span Recovery ......................................13
           4.2.2. Segment Recovery ...................................13
           4.2.3. End-to-End Recovery ................................14
      4.3. Grades of Recovery ........................................15
           4.3.1. Dedicated Protection ...............................15
           4.3.2. Shared Protection ..................................16