OBS网络中基于优先级与概率的偏射路由算法*

摘 要：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，提出了一种基于优先级与概率的偏射路由算法。该算法根据突发包的优先级和转发概率来控制突发包的偏射，并从网络突发阻塞概率的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；节点根据链路上指定的权值，按概率为分割突发包选择一条可以使网络突发阻塞概率最小的最佳偏射路由。仿真结果表明，虽然网络中可选路由数目的增加对网络性能的改善非常有限，但是该算法能够有效的降低整个网络的丢包率，并且得到的高优先级突发包的丢失率低于低优先级突发包的丢失率，从而很好的保障了网络的服务质量。故这种方法能够有效的提高OBS网络的性能。

Deflection routing algorithm based on priority and probability in optical burst switching networks

Abstract: 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 probability in optical burst switching networks is proposed. It controls the deflection of contending bursts according to the priority of bursts and the probability, and searches the optimum deflection path in terms of the burst blocking probability of networks. When competition occurs, low priority bursts are segmented, and the segmentation part of bursts are deflected to free links. For every source-to-destination node pair, different weights are assigned to the links. The switching node will select the optimum output link that the burst blocking probability of networks is least for the segmentation part of bursts according to the probability. Simulations show that although it is very limited to improve the OBS networks performance by increasing the number of the optional routing, the proposed algorithm can efficiently reduce the burst loss probability of entire networks, and the burst loss probability of the high-priority bursts are much less than those of the low-priority bursts. This mechanism also provides the good guarantee of QoS for OBS networks. So the scheme can efficiently improve the performance of OBS networks.