DREAM: dual routing engine architecture in multilayer and multidomain optical networks

With the development of large-scale multilayer and multidomain optical networks, the path computation process becomes increasingly complicated in consideration of various policies and constraints. In particular, to meet the rigid requirements of multiple layers and multiple domains, dynamic routing has become one of the key issues in GMPLS/ASON networks. In this article, a novel dual routing engine architecture in multilayer and multidomain scalable and constraint-aware policy-enabled optical networks, DREAM, is proposed. This new architecture exploits the advantages of both the GMPLS control plane and path computation element PCE. The cooperation of a group engine and a unit engine effectively optimizes the path computation process, especially under the multiple constraints. In this article, the functional compositions of dual routing engines, core elements of DREAM, are described in detail. Six cooperation modes between group and unit engines are investigated. Two different routing schemes (DRE-FPC and HDRE-BRPC) are proposed and evaluated on a DREAM-based testbed, which is able to support over 1000 nodes divided into 20 or more domains. Numerical results are given and analyzed based on the testbed. Some future discussion and exploration issues are presented in the conclusion.