Application-Level Evaluation of IEEE 802.1AS Synchronized Time and Linux for Distributed Real-Time Systems

The use of Ethernet and Linux is becoming common in industrial applications, even for those with real-time requirements, although neither of them were originally designed for this purpose. The emergence of Industry 4.0 (also known as Industrial Internet of Things, IIoT) has encouraged the evolution of these technologies to better handle real-time issues. On the one hand, Linux now supports mechanisms to configure certain real-time parameters, as well as core isolation and interrupt allocation facilities in multicore processors. On the other hand, the set of Ethernet standards IEEE 802.1 Time-Sensitive Networking (TSN) includes a high precision clock synchronization protocol (IEEE 802.1AS). The purpose of this work is to outline an execution framework for distributed systems based on TSN and Linux, which allows the execution of time-aware applications. We have studied and evaluated different configurations available for the proposed execution framework. In particular, a detailed characterization of the clock synchronization mechanism, from the application point of view, has been performed. Some conclusions about the current real-time capabilities of these technologies are also presented.