Using updated neighbor state information for efficient contention avoidance in OBS networks

In this paper, we introduce and evaluate a preventive contention avoidance protocol to reduce the burst loss probability in emerging OBS networks. The proposed solution reacts to highly loaded downstream node situations by preventively deflecting the bursts towards less loaded neighbors. To keep pace with OBS traffic dynamics while minimizing the related control overhead, we propose the current node state information to be propagated downstream in the burst control packet. As a result, accurate adjacent nodes state information can be maintained, improving either preventive or reactive deflection routing decisions. Using this information, two different routing heuristics are presented aiming to reduce the computational costs at intermediate nodes. Our proposals are discussed and further assessed by extensive simulation results, showing a significant burst loss reduction especially when the burst size increases.