Enforcing Timing Requirements in Time-Sensitive Networks

Much effort has been put into Time-Sensitive Networking for Cyber- Physical Systems. Methods and tools have been proposed to support the design and operation of such networks. However, the incorporation of novel technologies, such as computer vision, cloud integration, and decision-making for autonomy, requires an operation regimen that cannot always be modeled at design-time. In this paper, we introduce algorithms to determine whether the load imposed on a Time-Sensitive Networking is within bounds, and to extract formal properties from message headers in order to dynamically verify the network's temporal requirements. We also introduce a formalism based on Signal Temporal Logic to express such properties, a set of Time-Sensitive Networking-specific property monitors, and a lightweight verification engine that can check them at runtime with little overhead. These mechanisms are used by a Safety Enforcement Unit to continuously monitor the network, triggering actions such as best-effort and low-priority traffic cancellations whenever a property fails verification. We evaluated the proposed mechanisms on a prototype autonomous vehicle that uses a Time-Sensitive Networking to interconnect GNSS, IMU, LiDAR, RADAR, and Camera to an ECU. Results demon-strate that these mechanisms can run in real-time, consuming 3% of the processing power of one of the cores in the ECU.