An evaluation of Opportunistic Native Multicast

Hybrid multicast opportunistically combines Application Layer Multicast and native multicast protocols. This paper presents an evaluation of Opportunistic Native Multicast which uses the AMT multicast tunnelling protocol. We describe our opportunistic multicasting approach that tries to solve the islands phenomenon by building unicast tunnels to connect these islands while attempting to utilise the native multicast capability of the islands. It is expected that this hybrid approach will improve both efficiency and availability of multicast. We compare our approach to the ALM protocol SCRIBE. The comparison here was done using five metrics: Stress, Stretch, intra-island traffic, interisland traffic and Delivery rate. In all of them, our proposed model has shown improved results over ALM. Moreover, we investigated what effect the number of islands that the receivers are distributed into, has on performance.