Path Computation Element communication Protocol extension for relationship between LSPs and Attributes
draft-dhody-pce-association-attr-00

PCE Working Group                                               D. Dhody
Internet-Draft                                       Huawei Technologies
Intended status: Standards Track                                   Q. Wu
Expires: January 22, 2015                                         Huawei
                                                           July 21, 2014

     Path Computation Element communication Protocol extension for
                relationship between LSPs and Attributes
                  draft-dhody-pce-association-attr-00

Abstract

   The Path Computation Element (PCE) provides functions of path
   computation in support of traffic engineering in networks controlled
   by Multi-Protocol Label Switching (MPLS) and Generalized MPLS
   (GMPLS).

   This document defines a mechanism to create associations between a
   set of LSPs and a set of attributes (such as configuration parameters
   or behaviors).

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   carefully, as they describe your rights and restrictions with respect
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Motivation  . . . . . . . . . . . . . . . . . . . . . . . . .   3
     3.1.  Policy based Constraints  . . . . . . . . . . . . . . . .   3
     3.2.  Bundled requests  . . . . . . . . . . . . . . . . . . . .   4
   4.  Overview  . . . . . . . . . . . . . . . . . . . . . . . . . .   4
   5.  Attribute Association Group . . . . . . . . . . . . . . . . .   4
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   8.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   5
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .   5
     9.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Appendix A.  Contributor Addresses  . . . . . . . . . . . . . . .   6

1.  Introduction

   [RFC5440] describes the Path Computation Element communication
   Protocol (PCEP) which enables the communication between a Path
   Computation Client (PCC) and a Path Control Element (PCE), or between
   two PCEs based on the PCE architecture [RFC4655].

   [I-D.minei-pce-association-group] introduces a generic mechanism to
   create a grouping of LSPs which can then be used to define
   associations between a set of LSPs and a set of attributes (such as
   configuration parameters or behaviours).

   This document specifies a PCEP extension to associate one or more
   LSPs with a set of attributes, which includes, but not limited to -

   o  Configured Parameters

   o  Policies

   o  Behaviour

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1.1.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

2.  Terminology

   The following terminology is used in this document.

   AGID:  Association Group ID.

   LSR:  Label Switch Router.

   MPLS:  Multiprotocol Label Switching.

   PCC:  Path Computation Client.  Any client application requesting a
      path computation to be performed by a Path Computation Element.

   PCE:  Path Computation Element.  An entity (component, application,
      or network node) that is capable of computing a network path or
      route based on a network graph and applying computational
      constraints.

   PCEP:  Path Computation Element Communication Protocol.

3.  Motivation

   This section discusses in more detail the motivation and use cases
   for such a assosiation.

3.1.  Policy based Constraints

   In the context of policy-enabled path computation [RFC5394], path
   computation policies may be applied at both a PCC and a PCE.
   Consider an Label Switch Router (LSR) with a policy enabled PCC, it
   receives a service request via signaling, including over a Network-
   Network Interface (NNI) or User Network Interface (UNI) reference
   point, or receives a configuration request over a management
   interface to establish a service.  The PCC may also apply user- or
   service-specific policies to decide how the path selection process
   should be constrained, that is, which constraints, diversities,
   optimization criterion, and constraint relaxation strategies should
   be applied in order for the service LSP(s) to have a likelihood to be
   successfully established and provide necessary QoS and resilience
   against network failures.  The user- or service-specific policies
   applied to PCC and are then passed to the PCE along with the Path
   computation request, in the form of constraints [RFC5394].

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   PCEP speaker can use the generic mechanism as per
   [I-D.minei-pce-association-group] to assosiate a set of LSPs with
   policy and its resulting path computation constraints.  This way
   simplifying the path computation message exchanges.

3.2.  Bundled requests

   In some scenarios(e.g.,the topology example described in Section 4.6
   of [RFC6805]), there is a need to send multiple requests with the
   same constraints and attributes to the PCE.  Currently these requests
   are either sent in a separate path computation request (PCReq)
   messages or bundled together in one (or more) PCReq messages.  In
   either case, the constraints and attributes need to be encoded
   separately for each request even though they are exactly identical.

   If a assosiation is used to identify these constraints and attributes
   shared by multiple requests, thus simplifying the path computation
   message exchanges.

4.  Overview

   As per [I-D.minei-pce-association-group], LSPs are associated with
   other LSPs with which they interact by adding them to a common
   association group.  This document use the same association for
   attributes and called Attribute Association Group (AAG) based on the
   generic Association object.  This document defines a new association
   type called "Attribute Association Type" of value TBD.  An AAG can
   have one or more LSPs and its assosiated attributes.  The scope and
   handling of AAG identifier is similar to the generic association
   identifier defined in [I-D.minei-pce-association-group].

5.  Attribute Association Group

   The format of the Association object used for AAG is shown in
   Figure 1:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Type   |  Generic flags    |R| Type-specific flags             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             Association group id                              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   //            Optional TLVs                                    //
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                  Figure 1: The Association Object format

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   Type - TBD for the Path Protection Associaiton Type

6.  Security Considerations

   TBD

7.  IANA Considerations

   TBD

8.  Acknowledgments

   A special thanks to author of [I-D.minei-pce-association-group], this
   document borrow some of the text from it.

9.  References

9.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC4655]  Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
              Element (PCE)-Based Architecture", RFC 4655, August 2006.

   [RFC5440]  Vasseur, JP. and JL. Le Roux, "Path Computation Element
              (PCE) Communication Protocol (PCEP)", RFC 5440, March
              2009.

   [I-D.minei-pce-association-group]
              Minei, I., Crabbe, E., Sivabalan, S., Ananthakrishnan, H.,
              Zhang, X., and Y. Tanaka, "PCEP Extensions for
              establishing relationships between sets of LSPs", draft-
              minei-pce-association-group-00 (work in progress), June
              2014.

9.2.  Informative References

   [RFC5394]  Bryskin, I., Papadimitriou, D., Berger, L., and J. Ash,
              "Policy-Enabled Path Computation Framework", RFC 5394,
              December 2008.

   [RFC6805]  King, D. and A. Farrel, "The Application of the Path
              Computation Element Architecture to the Determination of a
              Sequence of Domains in MPLS and GMPLS", RFC 6805, November
              2012.

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Appendix A.  Contributor Addresses

   Xian Zhang
   Huawei Technologies
   Bantian, Longgang District
   Shenzhen  518129
   P.R.China

   EMail: zhang.xian@huawei.com

   Udayasree Palle
   Huawei Technologies
   Leela Palace
   Bangalore, Karnataka  560008
   INDIA

   EMail: udayasree.palle@huawei.com

Authors' Addresses

   Dhruv Dhody
   Huawei Technologies
   Leela Palace
   Bangalore, Karnataka  560008
   INDIA

   EMail: dhruv.ietf@gmail.com

   Qin Wu
   Huawei Technologies
   101 Software Avenue, Yuhua District
   Nanjing, Jiangsu  210012
   China

   EMail: sunseawq@huawei.com

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