PERFORMANCE EVALUATION OF MULTICAST PROTOCOLS

In this paper, we report an analytic comparison of control bandwidth overheads (CBOs) fordifferent implementations of protocol independent multicast (PIM) variants in a hierarchicalnetwork environment using combinatorial technique. We find that over networks with severalnumbers of hierarchies PIM variants can have significantly different CBO per group member. Inparticular, the modified dense mode (DM) with state refresh (DMSR) typically has significantlylower CBO per group member than DM with flood and prune (DMFP) mechanism. Also studiedis the precise measure of the relative performance between sparse mode (SM) and source specificmulticast (SSM) protocols. The results show that the overhead costs of these protocols dependstrongly on the choice of the protocol and the operating conditions present. Our findings show thatat low network utilisation (i.e., a sparse network) there is a great sensitivity as SM is by far themost efficient protocol. The performance difference between SSM and DMSR protocols is alsosignificant as SSM is better than DMSR for small groups while for large groups DMSR is superior.These results provide useful information to the network community, particularly networkdesigners, integrators and users. Keywords: Control bandwidth overhead, Hierarchical networks, Multicast, Sensitivity, Networkutilisation.