RoMR: Robust multicast routing in mobile wireless networks

Support for multicast services is crucial for content distribution in mobile wireless networks (MWNs). Efficient multicasting in MWNs faces challenges not encountered in other types of networks such as the mobility of nodes, the tenuous status of communication links, limited resources, and indefinite knowledge of the network topology. This paper addresses these challenges by providing a framework and architecture with proactive and reactive components to support multicasting in MWNs emphasizing reliability and efficiency of end-to-end packet delivery. The architecture includes the Robust Multicast Routing protocol (RoMR) to provide efficient multicast services for content distritbution MWNs. RoMR's architecture includes a proactive and reactive component. The proactive component calculates multiple multicast trees based on the prediction of future availability of the links and the assumption that the trees will become disconnected over time. The reactive components respond to changes in the network topology due to the mobility of the nodes and to changes in the multicast group's membership. The novelty of the proposed protocol stems from integrating techniques that have not previously been combined into a multicasting protocol and a unique method to calculate the relative weights of the links. In addition to the specifications of the protocol, a simulation framework was developed to test different implementations of the various components of RoMR. Simulations compared the performance of the basic version of RoMR to a version that ignored link weights, and to the Multicast Optimized Link State Routing (MOLSR) protocol, a source tree-based, topology-aware multicast protocol. A statistical analysis of the results showed that RoMR performed better, overall, than the other two protocols.