OBS网络中基于优先级与参数可调的偏射路由算法

A Deflection Routing Algorithm Based on Priority and Parameter-tunable in Optical Burst Switching Networks

为了保证OBS网络中不同优先级业务的服务质量和解决偏射算法在偏射控制上的问题,提出一种基于优先级与参数可调的偏射路由算法.该算法通过设置可调参数"偏射概率"来控制冲突突发包的偏射,并从可调丢包率和偏射路径长度意义上寻找最佳偏射路由.当冲突发生时,分割优先级低的突发包,并将分割突发包偏射到空闲的链路上;在空闲的链路中选择若干条"在偏射路径上第k级突发包和总突发包的可调丢失率最小"的路由作为候选路由,最后在这些候选路由中选择一条偏射路径长度最短的最佳偏射路由.仿真结果表明,该算法能够有效地降低整个网络的丢包率,很好地保护高优先级突发包的完整性,并且在一定程度上可以有效地减少端到端的传输时延,减轻偏置时间对偏射突发服务质量保证的压力,从而提高整个网络的性能.

In order to guarantee quality of service（QoS） of different priority bursts and solve the problem of deflection control of deflection algorithm in OBS networks,a deflection routing algorithm based on priority and parameter-tunable in OBS networks is proposed.It intercalates the definition of a tunable-parameter（deflection probability） to control the deflection of contending bursts,and searches the optimum deflection path in terms of the burst loss probability and the deflection path length.When competition occurs,low priority bursts are segmented,and the segmentation part of bursts are deflected to free links.The algorithm selects many candidate routes which the tunable-burst loss probability of the first k priority burst and overall bursts in the deflection path is the least.At last,it chooses the shortest deflection path.Simulations show that the algorithm can reduce the burst loss probability of entire networks and protect the integrity of some high priority bursts.It also can efficiently reduce the delay,and reduce the offset time deficit on QoS guarantee.So the scheme can improve the performance of OBS networks.