Usability of Legacy p2p Multicast in Multi-hop Ad hoc Networks: an Experimental Study

There has recently been an increasing interest in convergence of p2p and ad hoc network research. Actually, p2p systems and multihop ad hoc networks share similar features, such as self-organisation, decentralisation, self-healing, and so forth. It is thus interesting to understand if p2p systems designed for the wired Internet are suitable also for ad hoc networks and, if they are not, in which direction they should be improved. In this paper, we report our experience in running p2p applications in real multihop ad hoc network testbeds. Specifically, we used group-communication applications that require p2p systems made up of an overlay network and a p2p multicast protocol. In this paper, we present experimental results specifically related to the performance of a well-known p2p shared-tree multicast protocol (Scribe). Our results show that such a solution is far from being efficient on ad hoc networks. We emphasize that the structured multicast approach is one of the main causes of inefficiency, and suggest that stateless solutions could be preferable.