Active congestion control mechanism for non-cumulative layered multicasting

A new noncumulative layered multicast congestion control algorithm is proposed that can identify the location of congested branch(es) in the multicast tree and intelligently assign a dropping preference for each candidate layer. These preferences are assigned in a way that minimizes the number of affected receivers by dropping the corresponding layer. The algorithm assigns higher dropping preferences to the layers that cause simultaneous congestion in the multicast tree. It also minimizes the effect of receivers intentionally ignoring the congestion control algorithm, which provides tighter control of the receivers, and a bounded TCP-friendly behavior. Complexity analysis proves that the proposed algorithm has a linear computation time complexity. Simulation results show that the proposed congestion control algorithm in conjunction with a suitable layer coordination mechanism can increase the average normalized throughput of the receivers in the multicast session by more than 24%.