Virtual topology design for flexible periodic traffic demands

In recent years, two possible approaches have been investigated for solving the virtual topology design problem for periodic (multi-hour) traffic demands. The first approach attempts to design a static topology that can accommodate all the traffic variations over time. The second option is to determine an appropriate series of virtual topologies to accommodate the different traffic loads at different times. This can lead to some cost savings in terms of the number of transceivers needed, but it requires the use of costly reconfigurable switching equipment. In this paper we present an integer linear program (ILP) formulation for designing an optimal, stable virtual topology for time-varying demands. Unlike previous work in the area, we consider the case where the exact start and end times of the demands are not known beforehand, but can slide within a larger time window. Our novel design approach integrates the topology design problem with proper scheduling of the demands in time, to create an optimal static topology capable of handling the set of periodic traffic demands.