Label Advertisement Discipline for LDP FECs

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Document Type Active Internet-Draft (mpls WG)
Authors Kamran Raza  , Sami Boutros  , Luca Martini  , Nicolai Leymann 
Last updated 2014-03-09 (latest revision 2014-01-20)
Replaces draft-raza-mpls-ldp-applicability-label-adv
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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 

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Internet-Draft   Label Advertisement Discipline for LDP FECs   Jan 2014 
Copyright Notice 

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   This document is subject to BCP 78 and the IETF Trust's Legal 
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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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Internet-Draft   Label Advertisement Discipline for LDP FECs   Jan 2014 
  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 
  LDP FECs. 

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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Internet-Draft   Label Advertisement Discipline for LDP FECs   Jan 2014 
        | 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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Internet-Draft   Label Advertisement Discipline for LDP FECs   Jan 2014 
       - 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 

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Authors' Addresses 

  Kamran Raza 
  Cisco Systems, Inc. 
  2000 Innovation Drive, 
  Ottawa, ON K2K-3E8, Canada. 
  Sami Boutros 
  Cisco Systems, Inc. 
  3750 Cisco Way, 
  San Jose, CA 95134, USA. 
  Luca Martini 
  Cisco Systems, Inc. 
  9155 East Nichols Avenue, Suite 400, 
  Englewood, CO 80112, USA. 
  Nicolai Leymann 
  Deutsche Telekom AG, 
  Winterfeldtstrasse 21, 
  Berlin 10781, Germany. 

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