Application protocols for safety-critical CAN-networked systems

In the industrial and automotive appliances, distributed systems are more and more frequently used. They require the coordinate action of several units for the systems to operate correctly. Therefore the units must exchange each other information on their activities and this is done through serial communication networks. CAN is a simple protocol that rules the operation of these networks. However, the native CAN does not have such features like determinism and fault tolerance, which are required by safety-critical appliances. To get round of the CAN limitations, there are two solutions, namely the recourse to the so-called time-triggered (TT) protocols or the supplement of the native CAN with ad-hoc developed application protocols. After reviewing the CAN limitations, the paper discusses at first the TT protocols and then the application protocols enhancing determinism and fault tolerance of the CAN networks. At last, a novel CAN application protocol that outperforms the existing ones is outlined.