Pseudowire (PW) Endpoint Fast Failure Protection
RFC 8104

Document Type RFC - Proposed Standard (March 2017; No errata)
Last updated 2017-03-15
Replaces draft-ietf-pwe3-endpoint-fast-protection
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Stream WG state Submitted to IESG for Publication
Document shepherd Stewart Bryant
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IESG IESG state RFC 8104 (Proposed Standard)
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Responsible AD Deborah Brungard
Send notices to "Stewart Bryant" <stewart.bryant@gmail.com>
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Internet Engineering Task Force (IETF)                           Y. Shen
Request for Comments: 8104                              Juniper Networks
Category: Standards Track                                    R. Aggarwal
ISSN: 2070-1721                                             Arktan, Inc.
                                                           W. Henderickx
                                                                   Nokia
                                                                Y. Jiang
                                           Huawei Technologies Co., Ltd.
                                                              March 2017

            Pseudowire (PW) Endpoint Fast Failure Protection

Abstract

   This document specifies a fast mechanism for protecting pseudowires
   (PWs) transported by IP/MPLS tunnels against egress endpoint
   failures, including egress attachment circuit (AC) failure, egress
   provider edge (PE) failure, multi-segment PW terminating PE failure,
   and multi-segment PW switching PE failure.  Operating on the basis of
   multihomed customer edge (CE), redundant PWs, upstream label
   assignment, and context-specific label switching, the mechanism
   enables local repair to be performed by the router upstream adjacent
   to a failure.  The router can restore a PW in the order of tens of
   milliseconds, by rerouting traffic around the failure to a protector
   through a pre-established bypass tunnel.  Therefore, the mechanism
   can be used to reduce traffic loss before global repair reacts to the
   failure and the network converges on the topology changes due to the
   failure.

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
   http://www.rfc-editor.org/info/rfc8104.

Shen, et al.                 Standards Track                    [Page 1]
RFC 8104           PW Endpoint Fast Failure Protection        March 2017

Copyright Notice

   Copyright (c) 2017 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.

Shen, et al.                 Standards Track                    [Page 2]
RFC 8104           PW Endpoint Fast Failure Protection        March 2017

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   4
   2.  Specification of Requirements . . . . . . . . . . . . . . . .   5
   3.  Reference Models for Egress Endpoint Failures . . . . . . . .   5
     3.1.  Single-Segment PW . . . . . . . . . . . . . . . . . . . .   6
     3.2.  Multi-Segment PW  . . . . . . . . . . . . . . . . . . . .   9
   4.  Theory of Operation . . . . . . . . . . . . . . . . . . . . .  10
     4.1.  Applicability . . . . . . . . . . . . . . . . . . . . . .  10
     4.2.  Local Repair  . . . . . . . . . . . . . . . . . . . . . .  11
     4.3.  Context Identifier  . . . . . . . . . . . . . . . . . . .  14
       4.3.1.  Semantics . . . . . . . . . . . . . . . . . . . . . .  15
       4.3.2.  FEC . . . . . . . . . . . . . . . . . . . . . . . . .  16
       4.3.3.  IGP Advertisement and Path Computation  . . . . . . .  16
     4.4.  Protection Models . . . . . . . . . . . . . . . . . . . .  17
       4.4.1.  Co-located Protector  . . . . . . . . . . . . . . . .  17
       4.4.2.  Centralized Protector . . . . . . . . . . . . . . . .  19
     4.5.  Transport Tunnel  . . . . . . . . . . . . . . . . . . . .  20
     4.6.  Bypass Tunnel . . . . . . . . . . . . . . . . . . . . . .  21
     4.7.  Examples of Forwarding State  . . . . . . . . . . . . . .  22
       4.7.1.  Co-located Protector Model  . . . . . . . . . . . . .  22
       4.7.2.  Centralized Protector Model . . . . . . . . . . . . .  26
   5.  Restorative and Revertive Behaviors . . . . . . . . . . . . .  29
   6.  LDP Extensions  . . . . . . . . . . . . . . . . . . . . . . .  30
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