Dynamic reconfiguration based on balanced alternate routing algorithm (BARA) for all-optical wavelength-routed WDM networks

This paper studies the virtual topology reconfiguration problem for all-optical wavelength-routed WDM networks. We consider dynamic reconfiguration in response to changing traffic demands and formulate the problem as an Integer Programming problem with multiple optimization objectives, aiming at maximizing the network throughput, minimizing the average propagation delay over a lightpath, and minimizing the reconfiguration cost. We use heuristics to obtain approximate optimal solutions and propose a balanced alternate routing algorithm (BARA) based on a genetic algorithm. To make the problem computational tractable, we assume wavelength converters at each network node and approximately divide the optimization process into two relatively independent stages: route computation and lightpath routing. At the route computing stage, the aim is to compute a set of alternate routes for each pair of source and destination nodes in the network. At the lightpath routing stage, the aim is to decide an "optimal" route for each of the lightpaths between a pair of source and destination nodes from a set of alternate routes, and the decisions are subject to the formulated constraints and optimization objectives. Through simulation experiments, we show the effectiveness of BARA.