Towards adaptable TSN-based communications: A virtual Ethernet switch for embedded real-time systems.

Modern embedded real-time systems are experiencing a sharp increase in both the number, diversity, and data-intensive of the components---e.g., Electronic Control Units (ECUs) and sensors---, leading to newer challenges for these systems where deterministic communication and predictable performance are essential. Traditional communication standards are no longer sufficient to meet these new bandwidth requirements. As a consequence, Ethernet technology has been selected as a solution that can reach the required data-throughput. However, Ethernet native communication models lack the deterministic behavior required by real-time applications. To address this, Time-Sensitive Networking (TSN) extends Ethernet by introducing mechanisms for precise synchronization, scheduled traffic handling---e.g., by prioritizing and filtering data-flows---, and fault tolerance. In parallel, the consolidation of diverse software workloads on shared System-on-Chip platforms has driven the widespread adoption of virtualization. Virtualization allows heterogeneous applications---potentially running different operating systems and providing varied functionalities---to coexist on the same platform as virtual machines (VMs). This approach optimizes hardware utilization, reduces deployment costs, and enhances security and reliability by enforcing strong isolation between software components. Moreover, virtualization facilitates dynamic scaling of the embedded system by adding or removing virtual machines in response to changing demands, thereby offering better system adaptability. However, the shared use of physical interfaces, such as network ports, across multiple virtual machines presents challenges in maintaining predictable latency, which is critical for real-time applications. This thesis presents a TSN-enabled virtual Ethernet switch (VTSN) to accommodate the adaptability, predictability, and low-latency requirements of embedded real-time systems. Implemented in a dedicated virtual machine, VTSN provides full switching functionality and enables co-located VMs to communicate with external networks using TSN. The solution is described in detail and compared with a similar alternative. Finally, to validate the feasibility and adaptability of VTSN, two TSN-enabled real-time case studies, respectively, an autonomous driving car and a logistic facility, are analyzed. Part of the work presented in this thesis has been published in ``Time-Sensitive Autonomous Architectures'' by [D.Ferraro, L.Palazzi et al.], Springer, Real-Time Systems, 2023.