Off-line configuration of a MPLS over WDM network under time-varying offered traffic

Coupling MPLS traffic engineering on top of a wavelength-routed WDM layer offers great flexibility to operators to allocate traffic demands in their networks. We consider the problem of off-line joint configuration at both packet and optical layers. We consider time-variant offered traffic, and assume that the operator has knowledge of the traffic dynamics as a set of traffic matrices at different instants. A novel mixed integer linear programming (MILP) formulation is proposed, which takes as input this set of traffic matrices, and provides an optimal static configuration capable of accommodating the time-varying traffic. We provide a resolution strategy based on heuristics, and give numerical results for some sample cases. The proposed method is compared with a simple alternative approach for obtaining a single static solution, to show that our method utilizes much fewer resources. The solution under the proposed formulation is also compared with the set of solutions obtained by running distinct optimization problems at different instants, showing that the increase of resource is minimal. Hence our approach can provide a static configuration with about the same resources as a fully adaptable dynamical configuration.