IEEE 802.1AS Multi-Domain Aggregation for Virtualized Distributed Real-Time Systems

Cyber-physical systems like cars, mobile agriculture machines, or duty vehicles are increasingly connected to public networks. Thus, in addition to their inherent fault-tolerance requirements, there is a pressing need to design these systems cost-effectively to withstand cyber-attacks, i.e., to ensure cyber resiliency. This paper implements a cyber-resilient clock synchronization architecture that features fault-tolerant dependent clocks and a fault-tolerant average (FTA) using standardized protocols (e.g., IEEE 802.1AS) and open-source software (e.g., ACRN hypervisor). Our experiments show how OS diversification can improve the cyber resiliency of the FTA. Furthermore, our 24 h fault injection experiment demonstrates the robustness of the architecture against fail-silent grandmaster clocks and clock synchronization virtual machines. Therefore our architecture can serve as proof of concept to extend commercial offerings.