![]() ![]() ![]() The paper presents the proposed analysis and a performance comparison between the response times calculated by the analysis and the response times obtained through OMNeT++ simulations in three different scenarios. In this context, this work presents a response time analysis of TSN networks that encompasses the enhancements for scheduled traffic and preemption, in various combinations. Both amendments, that are now enrolled in the IEEE802.1Q-2018 standard, are very important for industrial networks, where scheduled traffic and low-latency real-time flows have to coexist, on the same network, with best-effort transmissions. ![]() In particular, the IEEE802.1Qbv-2015 amendment introduces enhancements that provide temporal isolation for scheduled traffic, i.e., a traffic class that requires transmission based on a known timescale, while the IEEE802.1Qbu-2016 introduces preemption as a mechanism to allow time-critical messages to interrupt ongoing non time-critical transmissions. The Time-Sensitive Networking (TSN) set of standards introduces in IEEE 802.1 switches and end stations novel features to meet the requirements of a broad spectrum of applications that are characterized by time-sensitive and mission-critical traffic flows. The work also points at the open challenges and future research directions. In this context, this work provides an overview of TSN in automotive applications and discusses the recent technological developments relevant to the adoption of TSN in automotive embedded systems. Moreover, throughout the development of automotive embedded systems, the safety and security requirements specified on these systems need to be duly taken into account. Some of the core phases in these processes include software architecture modeling, timing predictability verification, simulation, and hardware realization and deployment. In order to fully utilize the potential of these novel protocols in the automotive domain, TSN should be seamlessly integrated into the state-of-the-art and state-of-practice model-based development processes for automotive embedded systems. TSN standards offer, for example, a common notion of time through accurate and reliable clock synchronization, delay bounds for real-time traffic, time-driven transmissions, improved reliability, and much more. In a recent effort to meet these requirements, the IEEE Time-Sensitive Networking (TSN) task group has developed a set of standards that introduce novel features in Switched Ethernet. The functionality advancements and novel customer features that are currently found in modern automotive systems require high-bandwidth and low-latency in-vehicle communications, which become even more compelling for autonomous vehicles. ![]() Moreover, we present an extension to our method that finds the most favourable schedule for TT tasks with respect to ET schedulability, thus increasing the probability of the computed TT schedule remaining feasible when ET tasks are later added or changed. Using this novel technique, we show that we achieve equal or better schedulability and a faster schedule generation for most use-cases compared to simple polling approaches. The second step consists of modeling this envelope as a burst limiting constraint and building the TT schedule via simulating a modified Least-Laxity-First (LLF) scheduler. The approach first expresses a constraint for the TT task schedule in the form of a maximal affine envelope that guarantees that as long as the schedule generation respects this envelope, all sporadic ET tasks meet their deadline. We introduce a new paradigm for synthesizing TT schedules that guarantee the correct temporal behavior of TT tasks and the schedulability of sporadic ET tasks with arbitrary deadlines. In time-triggered systems, where the schedule table is predefined and statically configured at design time, sporadic event-triggered (ET) tasks are handled within specially dedicated slots or when time-triggered (TT) tasks finish their execution early. ![]()
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