Split and merge multicast: live media streaming with application level multicast

Application-level multicasting overcomes the problems linked with IP multicasting and provides an effective mechanism to support media streaming without placing a huge demand on the network. Webcasting live content using peer-to-peer technology is an excellent example of the use of application-level-multicast. One key problem associated with the peer-to-peer approach is the restriction on the content that can be distributed, because the upstream capacity of the peers is utilized to forward content to other peers. As the upstream bandwidth of most peers is restricted, Webcasting high bandwidth content is a continuing problem with no satisfactory technique proposed to date. In this paper we present a solution to this problem. We first introduce the concept of inverted multicast and then build on that to present the concept of split and merge multicast, a technique that can be used to stream high bandwidth content to a large number of users, without any constraints imposed by upstream bandwidth. Simulation results demonstrate that the proposed technique can achieve significant benefits due to a reduction in the number of streams required from the source and also by improving the quality of the Webcast as perceived by the end-users.