Experimental Assessment of ReCANcentrate, a Replicated Star Topology for CAN

Distributed embedded control systems for safety-critical applications require a high level of dependability. Despite the existence of protocols such as TTP or FlexRay specifically developed to provide that level of dependability, there has also been an increasing interest in CAN, given its low-cost, electrical robustness, good real-time properties and widespread use. However, the use of CAN in these applications has been controversial due to dependability limitations. In order to overcome some of those limitations, namely those arising from the bus topology of CAN, several active star topologies have been proposed, such as CANcentrate and, more recently, ReCANcentrate¹, which incorporates redundant hubs. In this paper we focus on the experimental assessment of ReCANcentrate, based on a prototype implementation using CAN COTS components. The experimental results illustrate the capabilities to detect and isolate faulty nodes, links and hubs, with transparent fault masking at the bit level, which is achieved by keeping all redundant hubs synchronized with the bit stream.