Mobility and its impact on the performance of hierarchical multicast retransmission

Although the application level hierarchical retransmission framework has been shown to be effective in providing reliable multicast transmission, it requires retransmission tree hierarchy construction and maintenance. If the retransmission tree is not congruent with the underlying multicast transmission tree, it results in performance degradation. For multicast networks with mobile hosts, the multicast transmission tree changes with great frequency. We examine the performance degradation due to the mobility of receivers and propose a retransmission hierarchy maintenance scheme to alleviate the problem. Simulation is done to measure the network overhead and latency of the proposed scheme. The proposed scheme is shown to exhibit significant improvement over the conventional hierarchical multicast retransmission scheme.