Path Computation Element (pce)

Last Modified: 2008-04-23

Additional information is available at tools.ietf.org/wg/pce

Chair(s):

  • JP Vasseur <jpv@cisco.com>

  • Adrian Farrel <adrian@olddog.co.uk>

    Routing Area Director(s):

  • Ross Callon <rcallon@juniper.net>
  • David Ward <dward@cisco.com>

    Routing Area Advisor:

  • Ross Callon <rcallon@juniper.net>

    Mailing Lists:

    General Discussion: pce@ietf.org
    To Subscribe: pce-request@ietf.org
    In Body: subscribe pce
    Archive: http://www.ietf.org/mail-archive/web/pce/

    Description of Working Group:

    The PCE Working Group is chartered to specify a Path Computation
    Element
    (PCE) based architecture for the computation of paths for MPLS and
    GMPLS
    Traffic Engineering LSPs.

    In this architecture path computation does not occur on the head-end
    (ingress) LSR, but on some other path computation entity that may
    physically not be located on the head-end LSR.

    The PCE WG will work on application of this model within a single
    domain
    or within a small group of domains (where a domain is a layer, IGP area
    or Autonomous System with limited visibility from the head-end LSR).
    At this time, applying this model to large groups of domains such as
    the
    Internet is not thought to be possible, and the PCE WG will not spend
    energy on that topic.

    The WG will specify a protocol for communication between LSRs (termed
    Path Computation Clients - PCCs) and PCEs, and between cooperating
    PCEs.
    This protocol will be capable of representing requests for path
    computation including a full set of constraints, will be able to return
    multiple paths, and will include security mechanisms such as
    authentication and confidentiality.

    The WG will determine requirements for extensions to existing routing
    and signaling protocols in support of PCE discovery and signaling of
    inter-domain paths. Candidate protocols for extensions are RSVP-TE,
    OSPF-TE, ISIS-TE and BGP. Any necessary extensions will be produced in
    collaboration with the Working Groups responsible for the protocols.

    The Working Group will also work on the definition of metrics to
    evaluate path quality, scalability, responsiveness and robustness of
    path computation models.

    Work Items:

    - Functional specification of MPLS and GMPLS Traffic Engineered LSP
    path
    computation models involving Path Computation Element(s). This
    includes the case of computing the paths of intra and inter-domain
    TE LSPs. Such path computation includes the generation of primary,
    protection and recovery paths, as well as computations for
    (local/global) reoptimization and load balancing. The WG will address
    the inter-area (single IGP domain) scenario first. WG progress will be
    evaluated before inter-AS related work is started.

    - Specification of the PCE-based architecture.

    - Specification of requirements and protocol extensions related to
    the policy, and security aspects of PCE-based path computation
    involving
    PCEs of multiple administrative entities.

    - In cooperation with protocol specific Working Group (OSPF, ISIS, IDR,
    MPLS, CCAMP), development of routing (OSPF, ISIS, BGP) and LSP
    signaling (RSVP-TE) extensions required to support PCE-based path
    computation models.

    - Specification of techniques in support of PCE discovery within and
    across domains. Where such techniques result in the extensions of
    existing protocols (e.g., OSPF, ISIS or BGP), this work will be done in
    conjunction with the appropriate WGs.

    - Specification of a new communication protocol for use between a PCC
    and a PCE, and between PCEs. A single protocol will be selected from
    among candidates that include the existing protocols defined in other
    WGs.

    - Definition of objective metrics to evaluate various criteria such as
    the measurement of path quality, response time, robustness and
    scalability of path computation models.

    Review of the document "Requirements for path computation element in
    GMPLS inter-domain networks" produced by the CCAMP WG.

    Goals and Milestones:

    Done  Submit first draft of PCE architecture document
    Done  Submit first draft of PCE discovery requirements and protocol extensions documents
    Done  Submit first draft of the PCE communication protocol requirements
    Done  Submit first draft of the definition of objective metrics
    Done  Submit first draft of the PCE communication protocol specification
    Done  Submit PCE architecture specification to the IESG to be considered as Informational RFC
    Nov 2005  Submit first draft of applicability statement (describing the processes and procedures for the use of the PCE architecture, protocols and protocol extensions for inter-area MPLS and GMPLS Traffic Engineering)
    Done  Submit first draft of the MIB module for the PCE protocol
    Done  Submit PCE communication protocol requirements to the IESG to be considered as an Informational RFC
    Done  Submit PCE discovery protocol extensions specifications to the IESG to be considered as a Proposed Standard
    Done  Submit PCE communication protocol specification to the IESG to be considered as a Proposed Standard
    Feb 2006  Submit the applicability and metrics documents to the considered as Informational RFCIESG to be
    Feb 2006  Evaluate WG progress, recharter or close

    Internet-Drafts:

    Path Computation Element (PCE) Communication Protocol (PCEP) (168600 bytes)
    PCC-PCE Communication and PCE Discovery Requirements for Inter-Layer Traffic Engineering (29675 bytes)
    Framework for PCE-Based Inter-Layer MPLS and GMPLS Traffic Engineering (79941 bytes)
    Policy-Enabled Path Computation Framework (79534 bytes)
    Inter-AS Requirements for the Path Computation Element Communication Protocol (PCEP) (35650 bytes)
    A Backward Recursive PCE-based Computation (BRPC) Procedure To Compute Shortest Constrained Inter-domain Traffic Engineering Label Switched Paths (41403 bytes)
    Definitions of Managed Objects for Path Computation Element Discovery (46036 bytes)
    Inclusion of Manageability Sections in PCE Working Group Drafts (28618 bytes)
    Extensions to the Path Computation Element Communication Protocol (PCEP) for Route Exclusions (38327 bytes)
    Preserving Topology Confidentiality in Inter-Domain Path Computation Using a Key-Based Mechanism (45082 bytes)
    Path Computation Element Communication Protocol (PCECP) Requirements and Protocol Extensions In Support of Global Concurrent Optimization (55632 bytes)
    Encoding of Objective Functions in Path Computation Element communication Protocol (PCEP) (40157 bytes)
    A set of monitoring tools for Path Computation Element based Architecture (39998 bytes)
    Extensions to the Path Computation Element communication Protocol (PCEP) for Inter-Layer MPLS and GMPLS Traffic Engineering (25673 bytes)

    Request For Comments:

    A Path Computation Element (PCE) Based Architecture (RFC 4655) (97561 bytes)
    Path Computation Element (PCE) Communication Protocol Generic Requirements (RFC 4657) (45284 bytes)
    Requirements for Path Computation Element (PCE) Discovery (RFC 4674) (40321 bytes)
    PCE Communication Protocol (PCECP) Specific Requirements for Inter-Area Multi Protocol Label Switching (MPLS) and Generalized MPLS (GMPLS) Traffic Engineering (RFC 4927) (25016 bytes)
    IS-IS Protocol Extensions for Path Computation Element (PCE) Discovery (RFC 5089) (34259 bytes)
    OSPF Protocol Extensions for Path Computation Element (PCE) Discovery (RFC 5088) (40936 bytes)
    IETF Secretariat - Please send questions, comments, and/or suggestions to ietf-web@ietf.org.

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