Stabilizing health monitoring for wireless sensor networks

Abstract

Wireless sensor networks (WSNs) comprised of low-cost devices tend to be unreliable, with failures a common phenomenon. Being able to accurately observe the network health status - of nodes of each type and links of each type - is essential to properly configure applications on WSN fabrics and to interpret the information collected from them. In this paper we study accurate network health monitoring in WSNs. Specifically, we reconsider the well-known problem of message-passing rooted spanning tree construction and its use in PIF (propagation of information with feedback) for the case of a WSN. We present a stabilizing protocol, Chowkidar, that is initiated upon demand; that is, it does not involve ongoing maintenance, and it terminates with accurate results, including detection of failure and restart during the monitoring process. Our protocol is distinguished from others in two important ways. Given the resource constraints of WSNs, it is message-efficient in that it uses only a few messages per node. And it tolerates ongoing node and link failure and node restart, in contrast to requiring that faults stop during convergence. We have implemented the protocol as part of enabling a network health status service that is tightly integrated with a remotely accessible wireless sensor network, testbed, Kansei, at The Ohio State University. We report on experimental results. © Springer-Verlag Berlin Heidelberg 2006.