An efficient preemption-based channel scheduling algorithm for service differentiation in OBS networks

Optical burst switching (OBS) is a promising switching technology for realization of an economical optical Internet. Quality-of-service (QoS) support is an important challenging issue of OBS networks, and a number of schemes have been proposed. However, the existing schemes have some limitations, such as QoS performance degradation, low wavelength utilization, and high implemental complexity. This paper proposes a bufferless preemption-based channel scheduling algorithm for service differentiation in OBS networks, which combines a preemption channel selection algorithm and a channel partitioning algorithm. The proposed preemption channel selection algorithm minimizes the length of preempted bursts to improve channel efficiency, and the channel partitioning algorithm controls the degree of service differentiation between service classes with low implemental complexity. An analytical model is derived and simulations are conducted to evaluate the performance. The results showed that the proposed scheme can improve channel efficiency and effectively provide controllable service differentiation for multi-class traffic in terms of the burst blocking probability and end-to-end throughput.