On hierarchical routing in wireless sensor networks

Hierarchical routing is a promising approach for point-to-point routing with very small routing state. While there are many theoretical analyses and high-level simulations demonstrating its benefits, there has been little work to evaluate it in a realistic wireless sensor network setting. Based on numerous proposed hierarchical routing infrastructures, we develop a framework that captures the common characteristics of the infrastructures and identifies design points where the infrastructures differ. We then evaluate the implementation of the framework in TOSSIM and on a 60-node testbed. We demonstrate that from the practical perspective hierarchical routing is also an appealing routing approach for sensor networks. Despite only logarithmic routing state, it can offer low routing stretch: the average of ∼1.25 and the 99-th percentile of 2. Moreover, a hierarchical routing infrastructure can be autonomously bootstrapped and maintained by the nodes. By exploring the design points within our framework, the hierarchy maintenance protocol can optimize different metrics, such as the latency of bootstrapping and repairing the hierarchy after failures or the traffic volume, depending on the application requirements. Finally, we also identify a number of practical issues which we believe the applications employing hierarchical routing should be aware of.