Route optimization in optical burst switched networks considering the streamline effect

Route optimization in optical burst switching (OBS) networks is investigated in this paper. Two route optimization problems are studied. The first problem considers the network in the normal working state where all the links are working properly. The route for each flow is decided so as to minimize the overall network burst loss. The second problem considers the failure states apart from the normal working state. The primary and backup paths for each flow are determined in such a way to minimize the expected burst loss over the normal and failure states. We argue that route selection based on load balancing or the traditional Erlang B formula is not efficient because of an important feature called the streamline effect. We analyze the streamline effect and propose a more accurate loss estimation formula which considers the streamline effect. Based on this formula, we develop mixed integer linear programming (MILP) formulations for the two problems. Since the MILP-based solutions are computationally intensive, we develop heuristic algorithms. We verify the effectiveness of our algorithms through numerical results obtained by solving the MILP formulations with CPLEX and also through simulation results.