Path Computation Element Protocol (PCEP) for RSVP-TE

The MPLS RSVP-TE functionality is extended to provide a partial client-side implementation of the stateful Path Computation Element (PCE) architecture (draft-ietf-pce-stateful-pce). The PCE computes path for the traffic engineered LSPs (TE LSPs) of ingress routers that have been configured for external control. The ingress router that connects to a PCE is called a Path Computation Client (PCC). The PCC is configured with the Path Computation Client Protocol (PCEP) (defined in RFC 5440, but limited to the functionality supported on a stateful PCE only) to facilitate external path computing by a PCE. In this new functionality, the active stateful PCE sets parameters for the PCC's TE LSPs, such as bandwidth, path (ERO), and priority. The TE LSP parameters configured from the PCC's CLI are overridden by the PCE-provided parameters. The PCC re-signals the TE LSPs based on the path specified by the PCE. Since the PCE has a global view of the bandwidth demand in the network and performs external path computationsafter looking up the traffic engineering database, this feature provides a mechanism for offline control of TE LSPs in the MPLS RSVP TE enabled network. To enable external path computing by a PCE, include the lsp-external-controller statement on the PCC at the [edit mpls] and [edit mpls lsp lsp-name] hierarchy levels. To enable PCE to PCC communication, configure pcep on the PCC at the [edit protocols] hierarchy level.