Protocol Extension Requirement for Cooperation between PCE and Distributed Routing Controller in GMPLS Networks
Path Computation Element (PCE) is proposed for path computation in multi-layer and multi-domain networks where PCE can be implemented in centralized method or distributed method. In the former case, PCE can serve tens or hundreds of nodes simultaneously, while in the later case, each node is equipped with a PCE, which can be regarded as a distributed routing controller (DRC) in GMPLS networks providing similar path computation capability. PCE and DRC have different advantages in path computation respectively. PCE is suitable for cross-layer and cross-domain path computation, especially in multi- constraints environment. But distributed routing controller is good at path computation in parallel and distributed network control in local domain. A cooperative path computation architecture named Dual Routing Engine (DRE) is necessary in the future networks, for it based on the two path computation engines and can take the advantages of both centralized and distributed method. The corresponding PCE communication protocol extension and other protocol requirements for cooperation between PCE and distributed routing controller are listed in this document.