Exploring Use of Ethernet for In-Vehicle Control Applications: AFDX, TTEthernet, EtherCAT, and AVB

Vehicle communication networks are challenged by increasing demands for bandwidth, safety, and security. New data is coming into the vehicle from personal devices (e.g. mobile phones), infotainment systems, camera-based driver assistance, and wireless communication with other vehicles and infrastructure. Ethernet (IEEE 802.3) provides high levels of bandwidth and security, making it a potential solution to the challenges of vehicle communication networks. However, in order to be used in control applications, Ethernet must provide known timing performance (e.g. bounded latency and jitter), and in some cases redundancy. This paper explores use of Ethernet for in-vehicle control applications. It begins by providing an overview of four Ethernet-based protocols under consideration for in-vehicle control: Avionics Full Duplex Switched Ethernet (AFDX), Time-Triggered Ethernet (TTEthernet), Ethernet for Control Automation Technology (EtherCAT), and standard Ethernet (IEEE 802.1 including Audio Video Bridging). The paper continues with discussion of key topics related to use of these Ethernet protocols for in-vehicle control. The topics include cost, physical layer, topology, startup time, redundancy, timetriggered scheduling, security, gateways, and higher layer software (e.g. AUTOSAR). Given the real-time nature of the application domain, the paper devotes a section to latency analysis (for communication based on the Ethernet protocols), which computes the worst-case transmission time for control data from source to destination(s).