The Label Distribution Protocol (LDP) Implementation Survey Results
RFC 5038

Network Working Group                                          B. Thomas
Request for Comments: 5038                           Cisco Systems, Inc.
Category: Informational                                     L. Andersson
                                                                Acreo AB
                                                            October 2007

  The Label Distribution Protocol (LDP) Implementation Survey Results

Status of This Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Abstract

   Multiprotocol Label Switching (MPLS), described in RFC 3031, is a
   method for forwarding packets that uses short, fixed-length values
   carried by packets, called labels, to determine packet next hops.  A
   fundamental concept in MPLS is that two Label Switching Routers
   (LSRs) must agree on the meaning of the labels used to forward
   traffic between and through them.  This common understanding is
   achieved by using a set of procedures, called a Label Distribution
   Protocol (as described in RFC 3036) , by which one LSR informs
   another of label bindings it has made.  One such protocol, called
   LDP, is used by LSRs to distribute labels to support MPLS forwarding
   along normally routed paths.  This document reports on a survey of
   LDP implementations conducted in August 2002 as part of the process
   of advancing LDP from Proposed to Draft Standard.

Table of Contents

   1. Introduction ....................................................2
      1.1. The LDP Survey Form ........................................2
      1.2. LDP Survey Highlights ......................................3
   2. Survey Results for LDP Features .................................4
   3. Security Considerations .........................................7
   4. References ......................................................7
   Appendix A. Full LDP Survey Results ................................8
   Appendix B. LDP Implementation Survey Form ........................13

Thomas & Andersson           Informational                      [Page 1]
RFC 5038           LDP Implementation Survey Results        October 2007

1.  Introduction

   Multiprotocol Label Switching (MPLS) is a method for forwarding
   packets that uses short fixed-length values carried by packets,
   called labels, to determine packet next hops [RFC3031].  A
   fundamental MPLS concept is that two Label Switching Routers (LSRs)
   must agree on the meaning of the labels used to forward traffic
   between and through them.  This common understanding is achieved by
   using a set of procedures by which one LSR informs another of label
   bindings it has made.

   Label Distribution Protocol (LDP) specifies a set of procedures LSRs
   use to distribute labels to support MPLS forwarding along normally
   routed paths.  LDP was specified originally by [RFC3036].  The
   current LDP specification is [RFC5036], which obsoletes [RFC3036].
   [RFC3037] describes the applicability of LDP.

   This document reports on a survey of LDP implementations conducted in
   August 2002 as part of the process of advancing LDP from Proposed to
   Draft standard.

   This section highlights some of the survey results.  Section 2
   presents the survey results for LDP features, and Appendix A presents
   the survey results in full.  Appendix B contains a copy of the survey
   form.

1.1.  The LDP Survey Form

   The LDP implementation survey requested the following information
   about LDP implementation:

   -  Responding organization.  Provisions were made to accommodate
      organizations that wished to respond anonymously.

   -  The status, availability, and origin of the LDP implementation.

   -  The LDP features implemented and for each whether it was tested
      against an independent implementation.  The survey form listed
      each LDP feature defined by [RFC3036] and requested one of the
      following as the status of the feature:

         t: Tested against another independent implementation
         y: Implemented but not tested against independent
            implementation
         n: Not implemented
         x: Not applicable to this type of implementation

Thomas & Andersson           Informational                      [Page 2]
RFC 5038           LDP Implementation Survey Results        October 2007

      In addition, for the 'n' status, the responder could optionally
      provide the following additional information:

         s: RFC specification inadequate, unclear, or confusing
         u: Utility of feature unclear
         r: Feature not required for feature set implemented

   This document uses the following conventions for reporting survey