Formal evaluation and comparison of real time embedded automotive networks

Automotive constructors want to replace critical mechanical functions by electronical components communicating by a real time embedded network (X-by-Wire technologies) on future cars. To implement such critical functions, these networks have hard real-time and fault tolerance constraints. There exist two automotive protocol families: event-triggered (e.g. CAN) and time-triggered (e.g. TTP/C). The aim of this paper is to compare these two protocols efficiency using quality of service (QoS) criteria. A methodology based on timed automata modeling (UPPAAL) is used to obtain efficiency measurements. An example of X-by-Wire application (engine control) is used to show impact of network properties on application QoS. The X-by-Wire application QoS gives from application point of view the protocol efficiency.