Assessing and Extending SSM for Highly Dynamic Mobility Environments

Although application-layer multicast has deserved some attention in the last few years due to the failure to deploy multicast at the network layer, recent work at this level has come up with a promising solution: source specific multicast (SSM). Nevertheless, in spite of the reduction in complexity inherent to SSM, there are still several problems to solve, especially when mobility is concerned. In this paper, an analysis of the limitations and drawbacks of SSM in mobile environments is presented, showing that existing proposals still suffer from the complexity and overhead syndromes characteristic of previous multicast proposals. In addition to this analysis, the paper presents a simple proposal for SSM-based multicast in wireless environments that uses the concept of multicast servers in order to limit the instability of multicast trees under highly dynamic conditions. The evaluation of this proposal was carried out by prototyping and simulation, showing that it has several advantages over the current internet draft proposal for mobile SSM, with no performance costs