Multicast has wide applications in distributed interactive applications

online games

streaming media and etc.To meet the application layer multicast QoS requirement

this paper builds a multi-constrained application layer multicast tree model and tries to find the optimal spanning tree based on genetic algorithm and dichromatic coding. The algorithm can meet the real-time requirement and node load limit as well as minimize network resource consumption and take full advantage of network resources. It turns out to be featured by fast convergence and high reliability.