Hybrid broadcasting protocols: a comparative study

Video on demand (VoD) protocols is classified into two categories: proactive and reactive protocols. Proactive protocols are recommended to broadcast frequently requested (popular) movies. For less frequently requested (unpopular) videos reactive protocols perform much better in terms of bandwidth and hence are recommended. As the request frequency changes over time, VoD service providers are not able to optimally allocation to different ongoing requested movies. A hybrid broadcasting protocol that performs like reactive protocols at low workload and like proactive protocols at high workload is needed. Unfortunately, only few works have focused on this issue. In this paper we present a comparative study between previous known hydride protocols namely the universal broadcasting protocols (UD), the dynamic heuristic broadcasting protocol (DHB) and our recent hybrid protocol slotted stream tapping (SST). We show that SST outperforms the two others at low workloads. While at high workloads, UD and DHB provide a slight bandwidth saving, SST is more practical and extremely easier to implement.