Lightweight message tracing for debugging wireless sensor networks

Wireless sensor networks (WSNs) deployments are subjected not infrequently to complex runtime failures that are difficult to diagnose. Alas, debugging techniques for traditional distributed systems are inapplicable because of extreme resource constraints in WSNs, and existing WSN-specific debugging solutions address either only specific types of failures, focus on individual nodes, or exhibit high overheads hampering their scalability. Message tracing is a core issue underlying the efficient and effective debugging of WSNs. We propose a message tracing solution which addresses key challenges in WSNs - besides stringent resource constraints, these include out-of-order message arrivals and message losses - while being streamlined for the common case of successful in-order message transmission. Our approach reduces energy overhead significantly (up to 95% and on average 59% smaller) compared to state-of-the-art message tracing approaches making use of Lamport clocks. We demonstrate the effectiveness of our approach through case studies of several complex faults in three well-known distributed protocols.