uCast: Unified connectionless multicast for energy efficient content distribution in sensor networks

In this paper, we present uCast, a novel multicast protocol for energy efficient content distribution in sensor networks. We design uCast to support a large number of multicast sessions, especially when the number of destinations in a session is small. In uCast, we do not keep any state information relevant to ongoing multicast deliveries at intermediate nodes. Rather, we directly encode the multicast information in the packet headers and parse these headers at intermediate nodes using a scoreboard algorithm proposed in this paper. We demonstrate that 1) uCast is powerful enough to support multiple addressing and unicast routing schemes and 2) uCast is robust, efficient, and scalable in the face of changes in network topology, such as those introduced by energy conservation protocols. We systematically evaluate the performance of uCast through simulations, compare it with other state-of-the-art protocols, and collect preliminary data from a running system based on the Berkeley motes platform.