Path Computation Element (pce) ------------------------------ Charter Last Modified: 2009-11-05 Current Status: Active Working Group Chair(s): JP Vasseur Julien Meuric Routing Area Director(s): Stewart Bryant Adrian Farrel Routing Area Advisor: Adrian Farrel Secretary(ies): Daniel King Mailing Lists: General Discussion:pce@ietf.org To Subscribe: http://www.ietf.org/mailman/listinfo/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 Point to Point and Point to Multi-point 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 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 Jun 2008 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 PCE P2MP communication requirements Done Submit first draft of the PCE P2MP PCEP protocol extensions Sep 2008 Submit PCE P2MP communication requirements to the IESG to be considered as an Informational RFC Nov 2008 Submit applicability statement to the IESG as informational RFC Dec 2008 Submit PCE P2MP PCEP protocol extensions to the IESG to be considered as an Proposed Standard RFC Feb 2009 Submit the PCE MIB Internet-Draft to the IESG for consideration as Proposed Standard Done Submit applicability and metrics documents to the IESG Feb 2009 Evaluate WG progress, recharter or close Internet-Drafts: Posted Revised I-D Title ------ ------- -------------------------------------------- Nov 2005 Feb 2010 PCC-PCE Communication and PCE Discovery Requirements for Inter-Layer Traffic Engineering Dec 2006 Oct 2009 Definitions of Managed Objects for Path Computation Element Discovery Dec 2006 Oct 2009 Definitions of Textual Conventions for Path Computation Element Jan 2007 Feb 2010 Inclusion of Manageability Sections in PCE Working Group Drafts Sep 2007 Mar 2010 A set of monitoring tools for Path Computation Element based Architecture Feb 2008 Sep 2009 Extensions to the Path Computation Element communication Protocol (PCEP) for Inter-Layer MPLS and GMPLS Traffic Engineering Aug 2008 Jan 2010 PCC-PCE Communication Requirements for Point to Multipoint Multiprotocol Label Switching Traffic Engineering (MPLS-TE) Sep 2008 Mar 2010 Extensions to the Path Computation Element Communication Protocol (PCEP) for Point-to-Multipoint Traffic Engineering Label Switched Paths Sep 2008 Feb 2010 The use of SVEC (Synchronization VECtor) list for Synchronized dependent path computations Jan 2009 Mar 2010 PCE communication protocol(PCEP) Management Information Base Mar 2009 Oct 2009 PCC-PCE Communication Requirements for VPNs Jul 2009 Mar 2010 Conveying Vendor-Specific Constraints in the Path Computation Element Protocol Sep 2009 Mar 2010 PCEP Requirements for WSON Routing and Wavelength Assignment Request For Comments: RFC Stat Published Title ------- -- ----------- ------------------------------------ RFC4655 I Aug 2006 A Path Computation Element (PCE) Based Architecture RFC4657 I Sep 2006 Path Computation Element (PCE) Communication Protocol Generic Requirements RFC4674 I Oct 2006 Requirements for Path Computation Element (PCE) Discovery RFC4927 I Jun 2007 PCE Communication Protocol (PCECP) Specific Requirements for Inter-Area Multi Protocol Label Switching (MPLS) and Generalized MPLS (GMPLS) Traffic Engineering RFC5089 PS Jan 2008 IS-IS Protocol Extensions for Path Computation Element (PCE) Discovery RFC5088 PS Jan 2008 OSPF Protocol Extensions for Path Computation Element (PCE) Discovery RFC5376 I Nov 2008 Inter-AS Requirements for the Path Computation Element Communication Protocol (PCECP) RFC5394 I Dec 2008 Policy-Enabled Path Computation Framework RFC5440 PS Mar 2009 Path Computation Element (PCE) Communication Protocol (PCEP) RFC5455 PS Mar 2009 Diff-Serv Aware Class Type Object for Path Computation Element Communication Protocol RFC5441 PS Apr 2009 A Backward Recursive PCE-Based Computation (BRPC) Procedure To Compute Shortest Constrained Inter-Domain Traffic Engineering Label Switched Paths RFC5521 PS Apr 2009 Extensions to the Path Computation Element Communication Protocol (PCEP) for Route Exclusions RFC5520 PS Apr 2009 Preserving Topology Confidentiality in Inter-Domain Path Computation Using a Path-Key-Based Mechanism RFC5541 PS Jun 2009 Encoding of Objective Functions in the Path Computation Element Communication Protocol (PCEP) RFC5557 PS Jul 2009 Path Computation Element Communication Protocol (PCEP) Requirements and Protocol Extensions in Support of Global Concurrent Optimization RFC5623 I Sep 2009 Framework for PCE-Based Inter-Layer MPLS and GMPLS Traffic Engineering RFC5671 I Oct 2009 Applicability of the Path Computation Element (PCE) to Point-to-Multipoint (P2MP) Multiprotocol Label Switching (MPLS) and Generalized MPLS (GMPLS) Traffic Engineering (TE)