NGL01-5: Reliability Enhanced Large-Scale Application Layer Multicast

Reliability has become the major concern in application layer multicast because the participating users may join and leave at will. The overlay network, built on-the-fly, is highly dynamic. It is getting worse in reality because single-tree based multicast structures are preferred, due to their efficient usage of network resources. In these single multicast tree based schemes, users´ departure may cause serious service disruption for all the downstream users. A new tree construction algorithm is proposed to enhance reliability for application layer multicast. It exploits the property that the participating users´ lifetime follow a Pareto distribution, which has the used better than new (UBTN) feature, and dynamically adjusts the multicast tree. The participating nodes are mapped into a hierarchy which is organized in such a way that it reflects the relative stability among the participating nodes. The proposed approach is light-weight and no a prior knowledge about users´ lifetime is needed. A minimum of 50% reduction can be achieved in terms of service disruption frequency. Detailed mathematical analysis and simulation results are presented to validate the proposed algorithm.