Fault-tolerant distributed systems based on fieldbuses may benefit to a great extent from the availabilityof semantically rich communication services,such as those provided by group communication, clock synchronization, membership and failure detection. This is specially true of distributed critical control applications. However, the migration of those services to the realm of simple fieldbuses, such as the native Controller Area Network (CAN) protocol family, presents non-negligible problems, since it lacks most of the functionality required of a fault-tolerant distributed system, such as reliable message broadcast guarantees, distributed node failure detection, and site membership services. As part of our endeavor to design a CAN-based infrastructure support for extremely reliable distributed computer control, dubbed CAN Enhanced Layer (CANELy), we have been addressing the problem of fault-tolerant communications on fieldbuses in a comprehensive way. In this paper, we show that ...