An Architecture for IP/LDP Fast Reroute Using Maximally Redundant Trees (MRT-FRR)
RFC 7812

Document Type RFC - Proposed Standard (June 2016; No errata)
Last updated 2016-06-16
Replaces draft-atlas-rtgwg-mrt-frr-architecture
Stream IETF
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Reviews
Stream WG state Submitted to IESG for Publication Jul 2015
Document shepherd Janos Farkas
Shepherd write-up Show (last changed 2015-12-10)
IESG IESG state RFC 7812 (Proposed Standard)
Consensus Boilerplate Yes
Telechat date
Responsible AD Alvaro Retana
Send notices to "Janos Farkas" <janos.farkas@ericsson.com>, aretana@cisco.com
IANA IANA review state Version Changed - Review Needed
IANA action state RFC-Ed-Ack
Internet Engineering Task Force (IETF)                          A. Atlas
Request for Comments: 7812                                     C. Bowers
Category: Standards Track                               Juniper Networks
ISSN: 2070-1721                                                G. Enyedi
                                                                Ericsson
                                                               June 2016

                An Architecture for IP/LDP Fast Reroute
               Using Maximally Redundant Trees (MRT-FRR)

Abstract

   This document defines the architecture for IP and LDP Fast Reroute
   using Maximally Redundant Trees (MRT-FRR).  MRT-FRR is a technology
   that gives link-protection and node-protection with 100% coverage in
   any network topology that is still connected after 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/rfc7812.

Copyright Notice

   Copyright (c) 2016 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.

Atlas, et al.                Standards Track                    [Page 1]
RFC 7812              MRT Unicast FRR Architecture             June 2016

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Importance of 100% Coverage . . . . . . . . . . . . . . .   4
     1.2.  Partial Deployment and Backwards Compatibility  . . . . .   5
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   5
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   5
   4.  Maximally Redundant Trees (MRT) . . . . . . . . . . . . . . .   7
   5.  MRT and Fast Reroute  . . . . . . . . . . . . . . . . . . . .   9
   6.  Unicast Forwarding with MRT Fast Reroute  . . . . . . . . . .   9
     6.1.  Introduction to MRT Forwarding Options  . . . . . . . . .  10
       6.1.1.  MRT LDP Labels  . . . . . . . . . . . . . . . . . . .  10
         6.1.1.1.  Topology-Scoped FEC Encoded Using a Single Label
                   (Option 1A) . . . . . . . . . . . . . . . . . . .  10
         6.1.1.2.  Topology and FEC Encoded Using a Two-Label Stack
                   (Option 1B) . . . . . . . . . . . . . . . . . . .  11
         6.1.1.3.  Compatibility of MRT LDP Label Options 1A and 1B   12
         6.1.1.4.  Required Support for MRT LDP Label Options  . . .  12
       6.1.2.  MRT IP Tunnels (Options 2A and 2B)  . . . . . . . . .  12
     6.2.  Forwarding LDP Unicast Traffic over MRT Paths . . . . . .  13
       6.2.1.  Forwarding LDP Traffic Using MRT LDP Label Option 1A   13
       6.2.2.  Forwarding LDP Traffic Using MRT LDP Label Option 1B   14
       6.2.3.  Other Considerations for Forwarding LDP Traffic Using
               MRT LDP Labels  . . . . . . . . . . . . . . . . . . .  14
       6.2.4.  Required Support for LDP Traffic  . . . . . . . . . .  14
     6.3.  Forwarding IP Unicast Traffic over MRT Paths  . . . . . .  14
       6.3.1.  Tunneling IP Traffic Using MRT LDP Labels . . . . . .  15
         6.3.1.1.  Tunneling IP Traffic Using MRT LDP Label Option
                   1A  . . . . . . . . . . . . . . . . . . . . . . .  15
         6.3.1.2.  Tunneling IP Traffic Using MRT LDP Label Option
                   1B  . . . . . . . . . . . . . . . . . . . . . . .  15
       6.3.2.  Tunneling IP Traffic Using MRT IP Tunnels . . . . . .  16
       6.3.3.  Required Support for IP Traffic . . . . . . . . . . .  16
   7.  MRT Island Formation  . . . . . . . . . . . . . . . . . . . .  16
     7.1.  IGP Area or Level . . . . . . . . . . . . . . . . . . . .  17
     7.2.  Support for a Specific MRT Profile  . . . . . . . . . . .  17
     7.3.  Excluding Additional Routers and Interfaces from the MRT
           Island  . . . . . . . . . . . . . . . . . . . . . . . . .  18
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