Dynamic alternative routing: load balancing and contention avoidance in optical burst switched networks

Abstract

The most critical challenge in the design of burst optical networks is burst contention, which occurs when multiple bursts contend for the same wavelength on the same link at a certain node simultaneously. The techniques to address this problem include contention resolutions as well as contention avoidance. In contention resolution approaches, conflicts are resolved in wavelength, time or space domain when they have occurred. In contention avoidance approaches, bursty traffic is distributed through routes that are dynamically re-computed or selected according to network congestion status to avoid potential conflicts in advance. Current dynamic routing schemes for OBS are all based on global information, resulting in bandwidth consumption at signaling channels and a considerable delay between network status change and adaptation of the routing tables. In this paper, we propose a novel dynamic routing selection mechanism based on local statistical information, namely <i>dynamic alternative routing</i>, to balance load and avoid contentions in OBS networks. In this mechanism, a route is dynamically selected from the primary path and the alternative route for an incoming burst. The simulation results show the blocking probability of the proposal is significantly reduced and load balancing is efficiently achieved compared to the general OBS.