Dependability-aware routing and scheduling for Time-Sensitive Networking

Time-Sensitive Networking (TSN) extends IEEE 802.1 Ethernet for safety-critical and real-time applications in several areas, for example, automotive, aerospace or industrial automation. However, many of these systems also have stringent security requirements, and security attacks may impair safety. Given a TSN-based distributed architecture, a set of applications with tasks and messages as well as a set of security and redundancy requirements, the authors are interested to synthesise a system configuration such that the real-time, safety and security requirements are upheld. The Timed Efficient Stream Loss-Tolerant Authentication (TESLA) low-resource multicast authentication protocol is used to guarantee the security requirements and redundant disjunct message routes to tolerate link failures. The authors consider that tasks are dispatched using a static cyclic schedule table and that the messages use the time-sensitive traffic class in TSN, which relies on schedule tables (called Gate Control Lists, GCLs) in the network switches. A configuration consists of the schedule tables for tasks as well as the disjoint routes and GCLs for messages. A Constraint Programing-based formulation, which can be used to find an optimal solution with respect to the cost function, is proposed. Additionally, a Simulated Annealing-based metaheuristic, which can find good solution for large test cases, is proposed. The authors evaluate both approaches on several test cases.