Routing In Optical Burst Switching Networks Research Articles

Improving Fairness With Novel Adaptive Routing in Optical Burst-Switched Networks

In most existing studies of optical burst-switched networks, adaptive routing is based on deflection routing and/or feedback from the past intervals which often introduces excessive transmission delay and architectural complexity. Our proposed novel adaptive routing schemes, however, consider the transient link congestion at the moment when the bursts arrive and have potential to reduce the overall burst loss probability. Moreover, they can utilize the same offset times for the same node pairs implying zero additional transmission delay and simplicity. The proposed hop-by-hop routing schemes also aim to address the intrinsic unfairness defect of existing popular signaling protocols by increasing the effective link utilization. The results show that the proposed schemes generally outperform shortest path routing and depending on the routing strategy involved, the network topology and the traffic load, this improvement can be substantial. We develop analytical loss models to demonstrate the need for such an adaptive routing scheme at each hop and show its effectiveness. We also verify the analytical results by simulation.

A Study on Deflection Routing in Optical Burst-Switched Networks

A major concern in optical burst-switched networks is contention,which occurs when multiple bursts contend for the same link. While a deflection routing protocol is proposed as one of the contention resolution techniques,there has been no appropriate deflection routing algorithm to find an alternate route. In this paper, we formulate a deflection routing problem based on the burst blocking rate resulting from resource contention in an optical burst-switched network. This algorithm minimizes the contention on the alternate path with the minimum distance. Furthermore, in this paper, we develop an analytical model for the deflection routing time when deflection routing is performed to resolve contention. In this model, we investigate the expected deflection routing time considering that the burst could be dropped even with deflection routing due to another contention on the alternate path. Simulations are conducted to show that there is an improvement in terms of burst loss rate and network throughput.