MPLS Upstream Label Assignment for LDP
RFC 6389

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Internet Engineering Task Force (IETF)                       R. Aggarwal
Request for Comments: 6389                              Juniper Networks
Category: Standards Track                                    JL. Le Roux
ISSN: 2070-1721                                                   Orange
                                                           November 2011

                 MPLS Upstream Label Assignment for LDP

Abstract

   This document describes procedures for distributing upstream-assigned
   labels for the Label Distribution Protocol (LDP).  It also describes
   how these procedures can be used for avoiding branch Label Switching
   Router (LSR) traffic replication on a LAN for LDP point-to-multipoint
   (P2MP) Label Switched Paths (LSPs).

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/rfc6389.

Copyright Notice

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

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   described in the Simplified BSD License.

Aggarwal & Le Roux           Standards Track                    [Page 1]
RFC 6389         MPLS Upstream Label Assignment for LDP    November 2011

   This document may contain material from IETF Documents or IETF
   Contributions published or made publicly available before November
   10, 2008.  The person(s) controlling the copyright in some of this
   material may not have granted the IETF Trust the right to allow
   modifications of such material outside the IETF Standards Process.
   Without obtaining an adequate license from the person(s) controlling
   the copyright in such materials, this document may not be modified
   outside the IETF Standards Process, and derivative works of it may
   not be created outside the IETF Standards Process, except to format
   it for publication as an RFC or to translate it into languages other
   than English.

Table of Contents

   1. Introduction ....................................................3
   2. Specification of Requirements ...................................3
   3. LDP Upstream Label Assignment Capability ........................3
   4. Distributing Upstream-Assigned Labels in LDP ....................4
      4.1. Procedures .................................................4
   5. LDP Tunnel Identifier Exchange ..................................5
   6. LDP Point-to-Multipoint LSPs on a LAN ...........................9
   7. IANA Considerations ............................................11
      7.1. LDP TLVs ..................................................11
      7.2. Interface Type Identifiers ................................11
   8. Security Considerations ........................................12
   9. Acknowledgements ...............................................12
   10. References ....................................................12
      10.1. Normative References .....................................12
      10.2. Informative References ...................................13

Aggarwal & Le Roux           Standards Track                    [Page 2]
RFC 6389         MPLS Upstream Label Assignment for LDP    November 2011

1.  Introduction

   This document describes procedures for distributing upstream-assigned
   labels [RFC5331] for Label Distribution Protocol (LDP) [RFC5036].
   These procedures follow the architecture for MPLS upstream label
   assignment described in [RFC5331].

   This document describes extensions to LDP that a Label Switching
   Router (LSR) can use to advertise whether the LSR supports upstream
   label assignment to its neighboring LSRs.

   This document also describes extensions to LDP to distribute
   upstream-assigned labels.

   The usage of MPLS upstream label assignment using LDP to avoid branch
   LSR traffic replication on a LAN for LDP point-to-multipoint (P2MP)
   Label Switched Paths (LSPs) [RFC6388] is also described.

2.  Specification of Requirements

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",