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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。
Network applications based on multimedia transmission all have urgent demands on quality of service (QoS), such as bandwidth, delay and packet loss rate. Finding the multicast tree that satisfies the above QoS requirements is an NP-complete problem. In the existing multi-constrained QoS multicast routing algorithms are mainly local search algorithm or centralized search algorithm, which can not guarantee to find the global solution in the real network. In this paper, an ant colony optimization algorithm based on cross-entropy is proposed to solve the problem of multi-constrained QoS multicast routing. NS2 simulation results show that the algorithm can quickly find the approximate optimal solution.