Schedulability analysis of multi-packet messages in segmented CAN

The CAN bus is one of the most used networks in distributed real-time systems. The CAN bus can be divided by means of bridges in order to distribute the network load among different segments and contribute positively to the schedulability of the system. On the other hand, CAN supports the fragmentation of a message in multiple packets when it does not fit into one single CAN frame. The schedulability analysis of CAN has been extensively studied in the literature. Although the proposed methods analyze non-segmented CAN buses, they can be applied to segmented networks. However, the techniques from the related literature obtain quite pessimistic results in the analysis of segmented CAN networks with multi-packet messages. This paper proposes a less pessimistic CAN schedulability analysis method for the mentioned kind of networks. Moreover, this optimized technique can be integrated with methods oriented to the holistic schedulability analysis of a complete distributed real-time system.