Multicast Video-on-Demand Service in an Enterprise Network with Client-Assisted Patching

Multicast video-on-demand (VoD) systems are scalable and cheap-to-operate. In such systems, a single stream is shared by a batch of common user requests. In this research, we adopt multicast communication technique in an enterprise network where multimedia data are stored in distributed servers. We consider batching with patching. Batching incurs service latency but increases the possibility of larger group formation. Patching eliminates this service latency and further improves the performance of multicast communication in VoD systems. However, in conventional patching, each shortly requested client requires a separate server stream to patch the missing portion. We consider a novel patching scheme called client-assisted patching which outperforms conventional patching. Clients' buffer of a multicast group can be used to patch the missing portion of the clients who will request the same movie shortly. The newly admitted client in turn can also provide patching stream to the later client. This scheme significantly reduces the server load without requiring larger client cache space than conventional patching scheme. The conserved server bandwidth can be used to serve more client requests. Simulation experiments show that our scheme is more scalable and cheap-to-operate than conventional patching.