Virtual Synchrony Guarantees for Cyber-Physical Systems

By integrating computational and physical elements through feedback loops, CPSs implement a wide range of safety-critical applications, from high-confidence medical systems to critical infrastructure control. Deployed systems must therefore provide highly dependable operation against unpredictable real- world dynamics. However, common CPS hardware—comprising battery-powered and severely resource-constrained devices inter- connected via low-power wireless—greatly complicates attaining the required communication guarantees. VIRTUS fills this gap by providing atomic multicast and view management atop resource- constrained devices, which together provide virtually synchronous executions that developers can leverage to apply established concepts from the dependable distributed systems literature. We build VIRTUS upon an existing best-effort communication layer, and formally prove the functional correctness of our mechanisms. We further show, through extensive real-world experiments, that VIRTUS incurs a limited performance penalty compared with best-effort communication. To the best of our knowledge, VIRTUS is the first system to provide virtual synchrony guarantees atop resource-constrained CPS hardware.