A New Proportional Differentiated QoS Scheme Based on Batch Scheduling and Preemption for Optical Burst Switching Networks

摘要

The proportional differentiated model is very convenient for network operators to quantitatively adjust the quality differentiation among service classes. And optical burst switching (OBS) is considered as the promising switching paradigm of optical internet. So it is very important for OBS to support the proportional differentiated model. A preemption scheme based on batch-scheduling is proposed to provide proportional differential QoS for OBS networks in the paper. The expected burst dropping probability equation of every service class is deduced from the proportional differentiated model. When a batch burst control packets and their corresponding bursts are completely scheduled by LAUC with burst arrival order and some bursts are scheduled unsuccessfully, the preemption scheme is triggered to keep proportional burst dropping probability among service classes according to the expected burst dropping probability equations. The proposed scheme adopts the batch scheduling based on LAUC and burst arrival scheduling order to decrease burst dropping probability. And it adopts the preemption scheme to keep proportional burst dropping probability among service classes. Simulation results show that the proposed scheme can provide proportional differential QoS and efficiently decrease the burst dropping probability.