An efficient dynamic offset time mechanism to reduce burst contention in OBS networks

Optical Burst Switching (OBS) is a switching paradigm to efficiently support the ever-growing broadband multimedia traffic over optical networks which has been proposed with the consideration that future optical networks should provide efficient support for bursty traffic. Although research in OBS networks has evolved from theoretical investigations to proof-of-concept demonstrations, several key issues need to be investigated further before OBS prototypes can clearly outperformed Optical Circuit Switched (OCS) networks. In OBS networks, data loss may occur when bursts contend for network resources. There have been several proposed solutions to resolve contention. Most contention resolution techniques only react to the contention, but do not share the contention information. Based on the presented offset time determination technologies, we propose a novel dynamic offset time mechanism which concerns how to adjust offset time at source. In this mechanism, the intermediate node will send a signal to the source to notice the contention. Source will adjust the offset time in different strategies according to the situation of the network. Numerical results demonstrate that the proposed mechanism effectively reduces the contention at the expense of the increase the packet average end-to-end delay.