QoS routing algorithm in overlay multicast network

In order to enhance the quality of multi-media service, in this paper, degree-constraint conditions are simultaneously concerned during the process of minimizing the maximal multicast delays. An integral method is employed to deal with the delay resulted from transportation and node processing. Based on this method, an optimization model for QoS-constrained Overlay multicast routing is introduced; and then, a heuristic algorithm for solving this model is proposed. The time complexity of the algorithm is O(|V|³), which is better than O(|V|⁴) of the complexities of most algorithms for solving the same problem, where V is the node number of the given network. Meanwhile, the simulation presented in this paper suggests that the quality of the solutions from our algorithm is better, i.e., there are less delays.