中文摘要：

基于多媒体传输的网络应用均对服务质量（quality of service,QoS）有迫切的需求,如带宽、延迟、丢包率等。寻找满足上述QoS要求的组播树问题是一个NP-完全问题。在已有的多约束QoS组播路由算法中主要是局部搜索算法或集中式搜索算法,这些均不能保证在实际网络中找到全局解。本文提出用基于交叉熵的蚁群优化算法来求解多约束QoS组播路由问题,NS2仿真结果表明该算法能够快速找到近似最优解。

英文摘要：

Many applications in network like multimedia transmission have stringent demands for quality of service （QoS）,such as bandwidth,delay,and packet loss rate.Finding the multicast tree that satisfies these requirements is an NP-complete problem.Among the existing algorithms for multiple QoS constrained multicast are local search algorithms or centralized algorithms,which cannot guarantee the finding of global solutions in a real network.In this paper,an ant colony algorithm based on cross-entropy was proposed for multiple QoS constrained multicast routing.Simulation results in the NS-2 environment indicated that this algorithm could quickly find the close-to-the-best solution.