Scalable Routing in Sensor Actuator Networks with Churn

Routing in wireless networks is inherently difficult since their network topologies are typically unstructured and unstable. Therefore, many routing protocols for ad-hoc networks and sensor networks revert to flooding to acquire routes to previously unknown destinations. However, such an approach does not scale to large networks, especially when nodes need to communicate with many different destinations. This paper advocates a novel approach, the scalable source routing (SSR) protocol. It combines overlay-like routing in a virtual network structure with source routing in the physical network structure. As a consequence, SSR can efficiently provide the routing semantics of a structured routing overlay, making it an efficient basis for the scalable implementation of fully decentralized applications. In T. Fuhrmann (2005) it has been demonstrated that SSR can almost entirely avoid flooding, thus leading to a both memory and message efficient routing mechanism for large unstructured networks. This paper extends SSR to unstable networks, i. e. networks with churn where nodes frequently join and leave, the latter potentially ungracefully