Online Protocol Verification in Wireless Sensor Networks via Non-intrusive Behavior Profiling

Wireless communication protocols are centric to Wireless Sensor Network (WSN) applications. However, WSN protocols are prune to defects, even after their field deployments. A convenient tool that can facilitate the detection of post-deployment protocol defects is of great importance to WSN practitioners. This paper presents Probe-I (sensor network Protocol behavior Inspector), a novel tool to obtain, visualize, and verify the behaviors of WSN protocols after their field deployments. Probe-I collects the protocol behaviors in a non-intrusive manner, i.e., via passively listening to the packet exchanges in the target network. Then with a role-oriented behavior modeling approach, Probe-I models the protocol behaviors node by node based on the sniffed packets, which well reflects how the target protocol performs in each node. This allows the WSN practitioners to readily see if the target protocol behaves as intended by simply verifying the correctness of the behavior metrics in a simple, baseline test. Finally, the verified metrics allow Probe-I to automatically check the protocol behaviors from time to time during the network lifetime. The suggested behavior discrepancy can unveil potential protocol defects. We apply Probe-I to verify two WSN data collection protocols, and find their design defects. It shows that Probe-I can substantially facilitate WSN protocol verification.