Routing and capacity assignment for survivable WDM network based protected working capacity envelope concept

Protected working capacity envelope concept has been proposed to simplify network management and operation in survivable WDM networks. Dynamic lightpath provisioning within working capacity envelope is only required to perform shortest path routing algorithm. Based on PWCE concept, we propose an efficient approximation approach, called Lagrangean relaxation with binary exponential reduction heuristics (LBER), aimed, to resolve the routing and capacity assignment (RCA) problem in survivable WDM networks to protect any single link failure. The task is first formulated as a mixed integer non-linear optimization problem in which the bottleneck link blocking probability for call setup is to be minimized. By sequentially solving a series of Lagrangean relaxation problems, the range of uncertainty of target blocking probability is reduced by half between the solutions of two adjacent problems such that the near optimal solution can be obtained in short time. We conduct a performance study on the proposed algorithms under different parameter settings. We further draw comparisons between LBER and a minimum working hop heuristic approach via experiments over two well known benchmark networks. Numerical results demonstrate that LBER outperforms minimum working hop approach for networks with both uniform and non-uniform demand distributions.