Proposed PCE Working Charter and Milestones

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 be removed from the head-end LSR. There may be many applications for such a model, but the primary concern of this Working Group is the application to inter-domain TE LSPs where a domain can be a layer, IGP area or Autonomous System such that there is limited topology visibility from the head-end LSR.

One of the main area for standardization is the specification of a communication protocol for use between LSRs (termed Path Computation Clients – PCCs) and PCEs, and between cooperating PCEs. This protocol must be capable of representing requests for path computation including a full set of constraints, must be able to return multiple paths with consideration of confidentiality and security, and must itself be secure.

The Working Group will determine requirements for extensions to existing routing and signaling protocols in support of such functions as PCE discovery and the secure and confidential signaling of inter-domain paths. Any necessary extensions will be produced in collaboration with the Working Groups responsible for the protocols.

The Working Group will also work on protocol-independent metrics defining path quality measurement criteria and scalability criteria related to path computation techniques.

Work Items:

• Functional specification of MPLS and GMPLS Traffic Engineered LSP path computation techniques involving Path Computation Element(s). This includes the case of intra and inter-domain (where a domain might be a specific layer, an IGP area or an Autonomous System) TE LSPs path computation and applies to Point to Point and Point to Multipoint TE LSPs. Such path computation techniques include primary, protection and recovery paths as well as load balancing techniques.
• Specification of the PCE-based architecture.
• 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 by PCE-based path computation techniques.
• Specification of techniques in support of PCE discovery within and across domains. Where such techniques result in the extensions of existing protocols, 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 protocol-independent metrics defining path quality measurement criteria and scalability criteria related to path computation techniques.
• Specification of requirements and protocol extensions related to the policy, security and confidentiality aspects of PCE-based path computation techniques involving PCEs of multiple administrative entities.
• Definition of MIBs and management procedures related to the new protocols, protocol extensions and operational elements defined by the WG.

The WG will work closely with the following other WGs for the derivation of requirements and for the specification of any necessary protocol extensions: CCAMP, MPLS, ISIS, OSPF and IDR;

Proposed WG Goals and initial Milestones (date to be determined)

Submit a requirements draft describing the function necessary for the use of PCE to compute the paths of inter-domain (G)MPLS TE LSPs.

Submit a draft describing the PCE architecture.

Submit a draft specifying requirements for a communication protocol for use between a PCC and a PCE, and between PCEs.

Submit a draft of a communication protocol for use between a PCC and a PCE, and between PCEs.

Submit an applicability draft describing the processes and procedures for the use of the PCE architecture, protocols and protocol extensions for inter-domain (G)MPLS Traffic Engineering.