Fault-Tolerant Support for Reliable Multicast in Mobile Wireless Systems: Design and Evaluation

In this paper we present a protocol for reliable multicast within a group of mobile hosts that communicate with a wired infrastructure by means of wireless technology. The protocol assumes that the wireless coverage may be incomplete and message losses could occur even within cells, due to physical obstructions or to the high error rate of the wireless technology, for example. A novel feature of our proposal is that it tolerates failures in the wired infrastructure, i.e., crashes of stationary hosts and partitions of wired links. In particular, upon such failures mobile hosts simply observe that the covered area has shrunk. The covered area will enlarge back to its original extension when the failure recovers. We evaluate our protocol by means of an extensive simulation analysis. The main findings of our analysis are: the protocol exhibits very good scalability properties; the performance degradation induced by fault-tolerance is moderate.