ABSTRACT
Controller area network (CAN) has been and will most likely remain a prominent network in passenger cars for at least two more car generations. One of the issues CAN will have to face is the growth of traffic with the increasing amount of data exchanged between electronic control units (ECUs). A car manufacturer has to make sure that the set of frames will be schedulable, that is, the response time of the frames is kept small enough to ensure that the freshness of the data is still acceptable when used at the receiver end. Clearly here, for most messages, even periodic ones, we are in the realm of soft real-time constraints: a deadline constraint can be occasionally missed 14_2without major consequences. However, the issue on CAN is that worst-case response times (WCRT) increase drastically with the load, which may explain why currently the bus utilization is typically kept at low levels (up to 30% or 40%) and why FlexRay is considered as a must for next generation architectures.
