Mobility Protocols and Handover Optimization: Design, Evaluation and Application

Chapter 9Handoff Optimization for Multicast Streaming

In this chapter, we propose a few optimization techniques that expedite the delivery of a multicast stream during handoff in a hierarchically scoped multicast architecture. First, we propose a hierarchically scoped multicast content distribution network, describe the functional components of the architecture and their implementation, introduce optimization techniques to reduce the join and leave latencies for multicast traffic, and finally compare performance results obtained in our prototype test bed for both optimized and nonoptimized handoffs. The previous chapters have focused on fast-handoff techniques for unicast traffic. However, in this chapter, we apply some of the optimization techniques that were discussed in Chapter 6 to provide fast delivery of multicast traffic in a hierarchically scoped multicast environment.

9.1 Summary of Key Contributions and Indicative Results

Currently, multicast-based content distribution systems lack flexible features such as local and global program management and automatic advertisement insertion. These systems also do not support fast handoff when the mobile moves between subnets. Unlike unicast traffic, multicast traffic is receiver-oriented. A mobile receiving multicast traffic is subject to handoff delay and associated media interruption due to multicast join latency during its movement between layer 2 access points or layer 3 subnets. Contributions to the multicast join latency ...