Reconfiguration of Survivable MPLS/WDM Networks

We present a novel group-based mechanism to reconfigure the virtual topology of survivable MPLS/WDM networks by using the existing shared protection backup resource. With this mechanism, lightpaths are divided into groups and those in the same group can be reconfigured simultaneously at one step. Ideally, this mechanism won’t incur any service disruption during the reconfiguration process. The optimal reconfiguration policy is obtained through solving following two problems: the Grouping problem which minimizes the reconfiguration steps, and the Sequencing problem which minimizes the network resource used during the reconfiguration process. We prove these two problems to be NP-hard and present efficient heuristic algorithms. A general mathematical method of rollout is applied to the heuristics to improve the solution quality. Numerical results are presented to show the optimal tradeoff between the reconfiguration duration and the required redundant capacity.