MPLS Working Group                                          Kamran Raza
Internet Draft                                             Sami Boutros
Updates: 5036, 4447, 5918, 6388, 3212                      Luca Martini
Intended status: Standards Track                    Cisco Systems, Inc.
Expires: July 19, 2014
                                                        Nicolai Leymann
                                                       Deutsche Telekom

                                                       January 20, 2014

                Label Advertisement Discipline for LDP FECs



  The label advertising behavior of an LDP speaker for a given FEC is
  governed by the FEC type and not necessarily by the LDP session's
  negotiated label advertisement mode. This document updates RFC 5036
  to make that fact clear, as well as updates RFC 3212, RFC 4447,
  RFC 5918, and RFC 6388 by specifying the label advertisement mode
  for all currently defined FECs.

 Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on July 19, 2014.

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Copyright Notice

   Copyright (c) 2014 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.

Table of Contents

  1. Introduction                                                     2
  2. Label Advertisement Discipline                                   3
     2.1. Update to RFC-5036                                          3
     2.2. Specification for LDP FECs                                  4
  3. Security Considerations                                          4
  4. IANA Considerations                                              4
  5. References                                                       5
     5.1. Normative References                                        5
     5.2. Informative References                                      5
  6. Acknowledgments                                                  5

1. Introduction

  Label Distribution Protocol (LDP) [RFC5036] allows label
  advertisement mode negotiation at the time of session establishment.
  LDP specification also dictates that only single label advertisement
  mode is negotiated, agreed and used for a given LDP session between
  two LSRs.

  The negotiated label advertisement mode defined in RFC 5036 and
  carried in the LDP Initialization message is only indicative. It
  indicates how the LDP speakers on a session will advertise labels for
  some FECs, but it is not a rule that restricts the speakers to behave
  in a specific way.  Furthermore, for some FEC types the advertising
  behavior of the LDP speaker is governed by the FEC type and not by

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  the negotiated behavior.

  This document updates [RFC5036] to make that fact clear, and updates
  [RFC3212], [RFC4447], [RFC5036], [RFC5918], and [RFC6388] to indicate
  for each FEC type that has already been defined whether the label
  binding advertisements for the FEC are constrained by the negotiated
  label advertisement mode or not. Furthermore, this document specifies
  the label advertisement mode to be used for all currently defined

2. Label Advertisement Discipline

   To remove any ambiguity and conflict regarding label advertisement
   discipline amongst different FEC types sharing a common LDP session,
   this document specifies a label advertisement disciplines for FEC

   This document introduces following types for specifying a label
   advertisement discipline for a FEC type:

     -  DU (Downstream Unsolicited)
     -  DoD (Downstream On Demand)
     -  As negotiated (DU or DoD)
     -  Upstream ([RFC6389])
     -  Not Applicable

2.1. Update to RFC-5036

   The section 3.5.3 of [RFC5036] is updated to add following two
   statements under the description of "A, Label Advertisement

     - Each document defining an LDP FEC must state the applicability
        of the negotiated label advertisement discipline for label
        binding advertisements for that FEC. If the negotiated label
        advertisement discipline does not apply to the FEC, the
        document must also explicitly state the discipline to be used
        for the FEC.

     - This document defines the label advertisement discipline for
        the following FEC types:

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        | FEC Type | FEC Name | Label advertisement discipline |
        | 0x01     | Wildcard | Not applicable                 |
        | 0x02     | Prefix   | As negotiated (DU or DoD)      |

2.2. Specification for LDP FECs

   Following is the specification of label advertisement disciplines to
   be used for currently defined LDP FEC types.

   | FEC  | FEC Name       | Label advertisement discipline |RFC   |
   | Type |                |                                |      |
   | 0x01 | Wildcard       | Not applicable                 | 5036 |
   | 0x02 | Prefix         | As negotiated (DU or DoD)      | 5036 |
   | 0x04 | CR-LSP         | DoD                            | 3212 |
   | 0x05 | Typed Wildcard | Not applicable                 | 5918 |
   | 0x06 | P2MP           | DU                             | 6388 |
   | 0x07 | MP2MP-up       | DU                             | 6388 |
   | 0x08 | MP2MP-down     | DU                             | 6388 |
   | 0x80 | PWid           | DU                             | 4447 |
   | 0x81 | Gen. PWid      | DU                             | 4447 |

  The above table also lists the RFC (in which given FEC type is
  defined), and hence this document updates all the above listed RFCs.

3. Security Considerations

   This document specification only clarifies the applicability of LDP
   session's label advertisement mode, and hence does not add any LDP
   security mechanics and considerations to those already defined in
   the LDP specification [RFC5036].

4. IANA Considerations

  This document mandates the specification of a label advertisement
  discipline for each defined FEC type, and hence extends IANA's
  "Forwarding Equivalence Class (FEC) Type Name Space" registry under
  IANA's "Label Distribution Protocol (LDP) Parameters" as follows:

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       - Add a new column titled "Label advertisement discipline" with
          following possible values:
            o DU
            o DoD
            o As negotiated (DU or DoD)
            o Upstream
            o Not applicable

       - For the existing FEC types, populate this column with the
          values listed under section 2.2.

5. References

5.1. Normative References

   [RFC5036] L. Andersson, I. Minei, and B. Thomas, "LDP
             Specification", RFC 5036, September 2007.

   [RFC3212] B. Jamoussi, et al., "Constraint-Based LSP Setup using
             LDP", RFC 3212, January 2002

   [RFC4447] L. Martini, Editor, E. Rosen, El-Aawar, T. Smith, G.
             Heron,  "Pseudowire Setup and Maintenance using the Label
             Distribution Protocol", RFC 4447, April 2006.

   [RFC5918] R. Asati, I. Minei, and B. Thomas, "Label Distribution
             Protocol Typed Wildcard FEC", RFC 5918, August 2010.

   [RFC6388] I. Minei, I. Wijnands, K. Kompella, and B. Thomas, "LDP
             Extensions for P2MP and MP2MP LSPs", RFC 6388, November

   [RFC6389] R. Aggarwal, and JL. Le Roux, "MPLS Upstream Label
             Assignment for LDP", RFC 6389, November 2011.

5.2. Informative References


6. Acknowledgments

   We acknowledge Eric Rosen and Rajiv Asati for their initial review
   and input on the document.

   This document was prepared using 2-Word-v2.0.template.dot.

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Authors' Addresses

  Kamran Raza
  Cisco Systems, Inc.
  2000 Innovation Drive,
  Ottawa, ON K2K-3E8, Canada.
  E-mail: skraza@cisco.com

  Sami Boutros
  Cisco Systems, Inc.
  3750 Cisco Way,
  San Jose, CA 95134, USA.
  E-mail: sboutros@cisco.com

  Luca Martini
  Cisco Systems, Inc.
  9155 East Nichols Avenue, Suite 400,
  Englewood, CO 80112, USA.
  E-mail: lmartini@cisco.com

  Nicolai Leymann
  Deutsche Telekom AG,
  Winterfeldtstrasse 21,
  Berlin 10781, Germany.
  E-mail: N.Leymann@telekom.de

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