HERMES: A Software Architecture for Visibility and Control in Wireless Sensor Network Deployments

Designing reliable software for sensor networks is challenging because application developers have little visibility into, and understanding of, the post-deployment behaviorof code executing on resource constrained nodes in remoteand ill-reproducible environments. To address this problem,this paper presents HERMES, a lightweight framework and prototype tool that provides fine-grained visibility and control of a sensor node’s software at run-time. HERMES’sarchitecture is based on the notion of interposition, which enables it to provide these properties in a minimally intrusive manner, without requiring any modification to software applications being observed and controlled. HERMES providesa general, extensible, and easy-to-use framework forspecifying which software components to observe and controlas well as when and how this observation and control is done. We have implemented and tested a fully functional prototype of HERMES for the SOS sensor operating system. Our performance evaluation, using real sensor nodesas well as cycle-accurate simulation, shows that HERMES successfully achieves its objective of providing fine-grained and dynamic visibility and control without incurring significant resource overheads. We demonstrate the utility and flexibility of HERMES by using our prototype to design, implement,and evaluate three case-studies: debugging and testing deployed sensor network applications, performing transparent software updates in sensor nodes, and implementingnetwork traffic shaping and resource policing.