Towards understanding the sensitivity of the reliability achievable by simplex and replicated star topologies in CAN

Star-based field buses are gaining importance in the context of highly-dependable systems. However, although the error-containment and fault-tolerance capabilities of different stars have been evaluated, no one had appropriately quantified the system dependability benefits stars actually yield. Thus, in previous work, we quantitatively demonstrated, for the case of CAN, that a simplex and a replicated star called CANcentrate and ReCANcentrate can improve the system reliability when compared with a bus. However, we characterized all the dependability-related aspects of the system and the network to favor whenever possible the bus; except in one case, in which we studied the benefits of the simplex star over the bus depending on the error-containment capabilities of the nodes. Thus, to completely understand the full potential of stars, it is still necessary to assess how variations in each one of those aspects affect the reliability achievable with them when compared with the bus. This paper presents two of the set of analyses we are carrying out in this direction.