Research On Key Technologies Of Optical Burst Switching In High Performance Computer

In 1990s ,the bandwidth of transmission has become very huge with the development of WDM and DWDM technologies. The record of the maximum bandwidth has reached T-byte. But the switching technologies have to complete the switching in electronic domain. Therefore, the switching speed is becoming the bottleneck that should be settled successfully. Meanwhile, the demand of optical switching is impending in high performance computer interconnetion networks.Optical burst switching(OBS) combines the character of optical circuit switching(OCS) and optical packet switching(OPS). It takes the burst packet as the minimum switching unit. This can reduce the complexity of core router and requirement of optical device. The burst packet can be transparent transmitted without O/E or E/O conversion, and it can get over the difficulty of electronic bottleneck. So OBS is a competitive switching model for next generation of optical networks and it will have a good application in the future.The basic theory and structure of OBS are introduced firstly in this paper. Some main technologies of OBS are described and analyzed, including packet assembly, reservation protocol, scheduling algorithm, the scheme of contention resolution and QoS strategy. These are the key technologies of OBS as the next generation of optical networks.The scheduling algorithm is carefully studied in the paper. On the base of the research on traditional scheduling algorithm, the priority-based burst rescheduling with void filling(PBR-VF) algorithm is proposed. It takes the LAUC-VF as the sub-algorithm and combines the rescheduling algorithm. The simulation result shows that, the proposed algorithm can provide better resource efficiency and the QoS of optical burst switching networks.The scheme of contention resolution is one of the key technologies of OBS, and it is researched particularly in this paper. For contention resolution in OBS, a new priority-based grouping and hybrid-assembly(GHA) policy is presented, which is combined with head-dropping and deflection routing scheme. Two concepts are proposed, which are the comparative length of contention burst and the point of deflection routing .The simulation result demonstrates that this policy can reduce packet loss probability, especially the packet with high priority. Therefore, it can be well used in the optical burst switched networks with QoS requirement.