Negotiating Strict Latency Limits for Dynamic Real-Time Services in Vehicular Time-Sensitive Networks

Future vehicles are expected to dynamically deploy in-vehicle applications within a Service-Oriented Architecture (SOA). Critical services operate under hard real-time constraints, which Time-Sensitive Networking (TSN) complements on the in-vehicle Ethernet layer. TSN ensures deterministic communication between critical services and its Credit-Based Shaper (CBS) supports dynamic resource reservations. However, the dynamic nature of service deployment challenges network resource configuration, since any new reservation may change the latency of already validated flows. In addition, standard methods of worst-case latency analysis for CBS have been found incorrect, and current TSN stream reservation procedures lack mechanisms to signal application layer Quality-of-Service (QoS) requirements or verify deadlines. In this paper, we propose a QoS negotiation scheme within the automotive SOA that interacts with the TSN network controller to reserve resources while ensuring latency bounds. We comparatively evaluate reservation schemes using worst-case analysis and simulations of a realistic In-Vehicle Network (IVN) for demonstrating their impact on QoS guarantees, resource utilization, and setup times. We find that only a reservation scheme utilizing per-queue delay budgets and network calculus provides valid configurations and guarantees acceptable latency bounds throughout the IVN. The proposed service negotiation mechanism efficiently establishes 450 vehicular network reservations in just 11ms.