NodeMD: Diagnosing Node-Level Faults in Remote Wireless Systems ; CU-CS-1017-06

Software failures in wireless sensor systems are notoriously difficult to debug. Resource constraints in wireless deployments substantially restrict visibility into the root causes of node-level system and application faults. At the same time, the high cost of deployment of wireless sensor systems often far exceeds the cumulative cost of all other sensor hardware, so that software failures that completely disable a node are prohibitively expensive to repair in realworld applications, e.g. by on-site visits to replace or reset nodes. We describe NodeMD, a deployment management system that successfully implements lightweight runtime detection, logging, and notification of software faults on wireless mote-class devices. NodeMD introduces a debug mode that catches a failure before it completely disables a node and drops into a state that enables further diagnosis and correction, thus avoiding on-site redeployment. We present detailed analyses of NodeMD on real world applications of wireless sensor systems.