Improving Fairness for Multi-Hop Bursts in Optical Burst Switching Networks

The loss probability of bursts in an optical burst switching (OBS) network tends to be proportional to the number of hops between the burst’s ingress and egress switches because no buffers are implemented for the data bursts at the core switches. This causes unfairness for multi-hop bursts. We propose a preemption scheme, called hop based preemption (HBP), in order to resolve the unfairness issues in OBS networks. In our scheme, a burst that has traveled through many nodes, but will travel through fewer nodes to arrive at a destination can preempt a channel from other scheduled bursts. We evaluated the performance of the HBP in simulated NSF and ARPA networks. The numerical results presented in this paper show that the HBP reduces unfairness for multi-hop bursts in OBS networks.