A Fair Channel Scheduling Algorithm in Optical Burst-Switched Networks

Among various signaling protocols designed for OBS networks, the most popular one is just-enough-time (JET) protocol. JET can utilize the network capacity efficiently and reduce end-to-end transmission delay effectively. However, it may suffer from an intrinsic deficiency -fairness problem. Fairness problem is a traditional problem existing in various kinds of networks. It not only results in a phenomenon that bursts with shorter hops are generally favored but also deteriorates the networks utilization. In this paper, we investigated this problem and proposed a fair channel scheduling algorithm as a solution. Generally speaking, there is usually a tradeoff between fairness and blocking performance. Hence, our objective is to keep balanced between the two conflicting metrics. It gives each burst a dynamic priority which is defined by several characteristics of the burst. When a contention occurs, the proposed scheme picks the preferable burst and drops the other one according to their priorities then. Simulation results show that our scheme can improve fairness without degrading dropping performance too much. In addition, it increases the effective link utilizations as well.