Remote Loop-Free Alternate (LFA) Fast Reroute (FRR)
RFC 7490

 
Document Type RFC - Proposed Standard (April 2015; No errata)
Last updated 2015-04-22
Replaces draft-shand-remote-lfa
Stream IETF
Formats plain text pdf html
Stream WG state Submitted to IESG for Publication Nov 2014
Consensus Yes
Document shepherd Alvaro Retana
Shepherd write-up Show (last changed 2014-09-29)
IESG IESG state RFC 7490 (Proposed Standard)
Telechat date
Responsible AD Alia Atlas
Send notices to rtgwg-chairs@ietf.org, draft-ietf-rtgwg-remote-lfa@ietf.org
IANA IANA review state Version Changed - Review Needed
IANA action state No IC
Internet Engineering Task Force (IETF)                         S. Bryant
Request for Comments: 7490                                   C. Filsfils
Category: Standards Track                                     S. Previdi
ISSN: 2070-1721                                            Cisco Systems
                                                                M. Shand
                                                 Independent Contributor
                                                                   N. So
                                                           Vinci Systems
                                                              April 2015

          Remote Loop-Free Alternate (LFA) Fast Reroute (FRR)

Abstract

   This document describes an extension to the basic IP fast reroute
   mechanism, described in RFC 5286, that provides additional backup
   connectivity for point-to-point link failures when none can be
   provided by the basic mechanisms.

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 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/rfc7490.

Copyright Notice

   Copyright (c) 2015 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.

Bryant, et al.               Standards Track                    [Page 1]
RFC 7490                     Remote LFA FRR                   April 2015

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Requirements Language . . . . . . . . . . . . . . . . . .   4
   3.  Overview of Solution  . . . . . . . . . . . . . . . . . . . .   4
   4.  Repair Paths  . . . . . . . . . . . . . . . . . . . . . . . .   6
     4.1.  Tunnels as Repair Paths . . . . . . . . . . . . . . . . .   6
     4.2.  Tunnel Requirements . . . . . . . . . . . . . . . . . . .   7
   5.  Construction of Repair Paths  . . . . . . . . . . . . . . . .   8
     5.1.  Identifying Required Tunneled Repair Paths  . . . . . . .   8
     5.2.  Determining Tunnel Endpoints  . . . . . . . . . . . . . .   8
       5.2.1.  Computing Repair Paths  . . . . . . . . . . . . . . .   9
       5.2.2.  Selecting Repair Paths  . . . . . . . . . . . . . . .  11
     5.3.  A Cost-Based RLFA Algorithm . . . . . . . . . . . . . . .  12
     5.4.  Interactions with IS-IS Overload, RFC 6987, and Costed
           Out Links . . . . . . . . . . . . . . . . . . . . . . . .  17
   6.  Example Application of Remote LFAs  . . . . . . . . . . . . .  17
   7.  Node Failures . . . . . . . . . . . . . . . . . . . . . . . .  18
   8.  Operation in an LDP Environment . . . . . . . . . . . . . . .  19
   9.  Analysis of Real World Topologies . . . . . . . . . . . . . .  21
     9.1.  Topology Details  . . . . . . . . . . . . . . . . . . . .  21
     9.2.  LFA Only  . . . . . . . . . . . . . . . . . . . . . . . .  22
     9.3.  RLFA  . . . . . . . . . . . . . . . . . . . . . . . . . .  22
     9.4.  Comparison of LFA and RLFA results  . . . . . . . . . . .  24
   10. Management and Operational Considerations . . . . . . . . . .  25
   11. Historical Note . . . . . . . . . . . . . . . . . . . . . . .  25
   12. Security Considerations . . . . . . . . . . . . . . . . . . .  25
   13. References  . . . . . . . . . . . . . . . . . . . . . . . . .  26
     13.1.  Normative References . . . . . . . . . . . . . . . . . .  26
     13.2.  Informative References . . . . . . . . . . . . . . . . .  26
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  28
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  29

Bryant, et al.               Standards Track                    [Page 2]
RFC 7490                     Remote LFA FRR                   April 2015
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