A Cooperative Framework for Reliable Multicast Forwarding in Mobile Ad Hoc NETworks

In this paper an innovative framework based on the cooperation between MAC and routing protocols is proposed with the purpose of improving the reliability of multicast transmissions in a Mobile Ad hoc NETwork (MANET). The proposed framework adds new features to the On-Demand Multicast Routing Protocol (ODMRP) and to the IEEE 802.11MAC layer. This choice allows to exploit the mesh-based nature of the ODMRP forwarding scheme, which offers higher reliability and connectivity among multicast members compared to other multicast routing protocols proposed for MANETs. Simulation results have shown the advantages achieved by the proposed solution compared to the straight forward application of legacy ODMRP when coupled with either the standard IEEE 802.11 MAC or the Multicast aware MAC Protocol (MMP). Several scenarios have been analyzed by varying the multicast group size, the node mobility, and by properly tuning the protocols' parameters (e.g., the maximum number of MAC layer retransmissions). In the various examined scenarios, the proposed solution improves the performance in terms of successfully conveyed multicast packets with a negligible increase in the signaling overhead necessary to guarantee reliable data delivery.