Efficient Multicasting in MANET Using RSGM Technique

In mobile ad hoc network (MANET) the designing of multicast transmission is a challenge due to the difficulty in group membership management, multicast packet forwarding, and the maintenance of multicast structure over the dynamic network topology for a large group size or network size. For this, we propose a novel Robust and Scalable Geographic Multicast Protocol (RSGM). Several virtual architectures are used in the protocol without need of maintaining state information for more robust and scalable membership management and packet forwarding in the presence of high network dynamics due to unstable wireless channels and node movements. Specifically, scalable and efficient group membership management is performed through a virtual-zone-based structure, and the location service for group members is integrated with the membership management. Both the control messages and data packets are forwarded along efficient tree-like paths, but there is no need to explicitly create and actively maintain a tree structure. The stateless virtual-tree-based structures significantly reduce the tree management overhead, support more efficient transmissions, and make the transmissions much more robust to dynamics. Geographic forwarding is used to achieve further scalability and robustness. To avoid periodic flooding of the source information throughout the network, an efficient source tracking mechanism is designed. The results demonstrate that RSGM can scale to a large group size and a large network size, and can more efficiently support multiple multicast groups in the network. Compared to existing protocols ODMRP and SPBM, RSGM achieves a significantly higher delivery ratio under all circumstances, with different moving speeds, node densities, group sizes, number of groups, and network sizes. RSGM also has the minimum control overhead and joining delay.