Routing path optimization in optical burst switched networks

Abstract

It is usually assumed that optical burst switched (OBS) networks employ shortest path routing along with next- hop burst forwarding. Shortest path routing minimizes delay and optimizes the utilization of resources, however, it often causes certain links to become congested while others remain underutilized. In a buffer-less OBS network in which burst drop probability is the primary metric of interest, the existence of a few highly congested links may lead to unacceptable performance for the entire network. In this paper, we take a traffic engineering approach to path selection in OBS networks with the objective of balancing the traffic across the network links in order to reduce congestion and improve overall performance. We present an approximate integer linear optimization problem, as well as a simple integer relaxation heuristic to solve the problem efficiently for large networks. Numerical results demonstrate that our approach is effective in reducing the network-wide burst drop probability, in many cases significantly, over shortest path routing.