Adaptive Proportional Flow Routing in Optical Burst Switching Networks

In this paper, we investigate the problem of multipath dynamic traffic routing in optical burst switching (OBS) networks. In this work, traffic is split among the multiple link-disjoint paths between each source and destination pair. Taking into consideration the packet reordering problem, we propose a new adaptive proportional routing scheme that operates on flow level. The objective of the proposed scheme is to reduce the overall burst loss in the network and at the same time avoid the packet out-of-sequence arrival problem. This is achieved by adaptively adjusting the traffic flow proportions assigned to the multiple paths between a source and destination pair based on the measurement of the impact of the offered traffic load on each of them in the past. When a new flow arrives, an appropriate path is chosen for it based on the calculated flow proportions. In addition, burst assembly time between different paths can also be adjusted to further enhance the performance. Through extensive simulations, we show that the proposed flow-based multi-path traffic routing approach not only provides significantly better burst loss performance than the basic equal-proportion and hop-length based traffic routing algorithms, but is also void of any packet re-orderings.