Scalable Explicit Multicasting on Internet: A Topological-Aware Approach

Explicit multicasting (Xcast) is a protocol to send data to multiple receivers in an efficient way. Compared with traditional stateful multicast, Xcast is based on a stateless approach that scales better in number of groups. Unfortunately, original Xcast brings up new challenges such as scalability of group size and efficiency issue. Therefore, Multiple Xcast (MXcast) and Generalized Xcast (GXcast) were proposed to retard the limitation of the group size by reconstructing the multicast group into multiple subgroups, and transferring multiple Xcast packets to different subgroups respectively. In this paper, we propose various sub grouping schemes and evaluate their performance based on hybrid simulation experiments. The results show that it can save up to 36.7% bandwidth consumption from Xcast to our proposed OGX cast in VoIP. The results reflect that the proposed scheme can improve the scalability of group size, achieve minimal packet delivery latency, reduce network bandwidth consumption, and reduce the loading of the source while compared with unicast and original Xcast, MXcast, and GXcast.