Routing Optimization in Optical Burst Switching Networks: a Multi-path Routing Approach

Abstract

AbstractThis chapter concerns routing optimization in optical burst switching (OBS) networks. OBS is a photonic network technology aiming at efficient transport of IP traffic. OBS architectures are in general bufferless and therefore sensitive to burst congestion. An overall burst loss probability (BLP) which adequately represents the congestion state of the entire network is the primary metric of interest in an OBS network. The network congestion can be reduced by using proper routing. We consider multi-path source routing and aim at optimal distribution of traffic over the network. In this context, we study three network loss models, a well-known loss model of an OBS network and two original approximate models. Since the objective function of each model is nonlinear, either linear programming formulations with piecewise linear approximations of this function or nonlinear optimization gradient methods can be used. The presented solution is based on nonlinear optimization; for this purpose we provide the formulas for calculation of partial derivatives. The main goal of this chapter is to show that the use of approximate models allows us to speed up significantly the optimization procedure without losing much accuracy. Moreover we show that our method effectively distributes the traffic over the network, and the overall BLP can be reduced compared with both shortest path routing and alternative routing.Keywordsmulti-path routingnetwork optimizationnonlinear optimizationoptical burst switching