A Network-Agnostic Approach to Enforcing Collision-Free Time-Triggered Communication

Collision-free time-triggered communication in distributed safety- and real-time-critical systems relies on approximately synchronized clocks, a-priori-defined communication schedules, and network guardians, synchronized in the same manner, which inhibit a node’s network access outside scheduled times. However, the ever-increasing complexity and interconnectivity of such systemsrender using contemporary network-aware guardians unsuitable: firstly, significant cost, complexity and certification efforts are incurred in developing new network protocol and topology specific guardian solutions. Secondly, contemporary network guardians lack the means to protect against repetitive cyberattacks that exhaust system synchrony.In this paper, we investigate a novel class of time-domain attacks, aimed at exhausting nodes by tampering with the synchrony of their network-agnostic guardians. We counter the attacks by introducing SyncGuard, the first, network-agnostic and time-domain attack-resilient guardian. SyncGuard-equipped systems avoid synchrony exhaustion attacks by jointly coordinating network access and node-rejuvenation.