Using BGP to Bind MPLS Labels to Address Prefixes
RFC 8277

Document Type RFC - Proposed Standard (October 2017; No errata)
Obsoletes RFC 3107
Last updated 2017-10-19
Replaces draft-rosen-mpls-rfc3107bis
Stream IETF
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Stream WG state Submitted to IESG for Publication
Document shepherd Loa Andersson
Shepherd write-up Show (last changed 2017-05-29)
IESG IESG state RFC 8277 (Proposed Standard)
Consensus Boilerplate Yes
Telechat date
Responsible AD Deborah Brungard
Send notices to Loa Andersson <loa@pi.nu>
IANA IANA review state Version Changed - Review Needed
IANA action state RFC-Ed-Ack
Internet Engineering Task Force (IETF)                          E. Rosen
Request for Comments: 8277                        Juniper Networks, Inc.
Obsoletes: 3107                                             October 2017
Category: Standards Track
ISSN: 2070-1721

           Using BGP to Bind MPLS Labels to Address Prefixes

Abstract

   This document specifies a set of procedures for using BGP to
   advertise that a specified router has bound a specified MPLS label
   (or a specified sequence of MPLS labels organized as a contiguous
   part of a label stack) to a specified address prefix.  This can be
   done by sending a BGP UPDATE message whose Network Layer Reachability
   Information field contains both the prefix and the MPLS label(s) and
   whose Next Hop field identifies the node at which said prefix is
   bound to said label(s).  This document obsoletes RFC 3107.

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
   https://www.rfc-editor.org/info/rfc8277.

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
   (https://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.

Rosen                        Standards Track                    [Page 1]
RFC 8277            BGP and Labeled Address Prefixes        October 2017

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Using BGP to Bind an Address Prefix to One or More MPLS
       Labels  . . . . . . . . . . . . . . . . . . . . . . . . . . .   4
     2.1.  Multiple Labels Capability  . . . . . . . . . . . . . . .   6
     2.2.  NLRI Encoding When the Multiple Labels Capability Is
           Not Used  . . . . . . . . . . . . . . . . . . . . . . . .   8
     2.3.  NLRI Encoding When the Multiple Labels Capability Is Used  10
     2.4.  How to Explicitly Withdraw the Binding of a Label to a
           Prefix  . . . . . . . . . . . . . . . . . . . . . . . . .  12
     2.5.  Changing the Label That Is Bound to a Prefix  . . . . . .  13
   3.  Installing and/or Propagating SAFI-4 or SAFI-128 Routes . . .  14
     3.1.  Comparability of Routes . . . . . . . . . . . . . . . . .  14
     3.2.  Modification of Label(s) Field When Propagating . . . . .  14
       3.2.1.  When the Next Hop Field Is Unchanged  . . . . . . . .  14
       3.2.2.  When the Next Hop Field Is Changed  . . . . . . . . .  15
   4.  Data Plane  . . . . . . . . . . . . . . . . . . . . . . . . .  16
   5.  Relationship between SAFI-4 and SAFI-1 Routes . . . . . . . .  18
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  19
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  19
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  20
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  20
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  22
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  23
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  23

1.  Introduction

   [RFC3107] specifies encodings and procedures for using BGP to
   indicate that a particular router has bound either a single MPLS
   label or a sequence of MPLS labels to a particular address prefix.
   (A sequence of labels would be organized as a contiguous part of an
   MPLS label stack as specified in [RFC3031] and [RFC3032].)  This is
   done by sending a BGP UPDATE message whose Network Layer Reachability
   Information field contains both the prefix and the MPLS label(s) and
   whose Next Hop field identifies the node at which said prefix is
   bound to said label(s).  Each such UPDATE also advertises a path to
   the specified prefix via the specified next hop.

Rosen                        Standards Track                    [Page 2]
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