An enhanced approach of inter-domain path computation in hierarchical PCE-based GMPLS multi-region networks

An integrated hierarchical PCE model is proposed to relieve the path selection policy constraint by the parent PCE in the hierarchical PCE (H-PCE) framework. The parent and child PCEs are unified by routing at a higher level in this new model, where each PCE maintains the summarized information of all the other domains apart from its interior link states in the Traffic Engineering Database (TED). This article puts forward a new procedure named Source-driven Hierarchical PCE-based Computation (SHPC) to compute shortest inter-domain paths in this new model, which provides a better approach to the solution of routing problems in PCE-based GMPLS multi-region networks. Numeric results show that SHPC does not ensure the best effectiveness of wavelength utilization but it achieves the lowest blocking probability in the IP-over-DWDM multi-domain environment under the scheme of routing with distributed wavelength assignment (R+DWA), which has been investigated and validated in the Dual Routing Engine (DRE) experimental platform.