Fault Tolerance Characteristics of FlexRay Central Devices

FlexRay is a communication system targeted at, among other things, fault tolerant applications. In contrast to some other communication systems, FlexRay systems often contain a central device such as an active star. Due to their ability to isolate portions of the communication system central devices offer opportunities to mitigate certain faults. This paper presents several alternatives for the central device of a FlexRay system, specifically active stars, FlexRay switches, and Central Bus Guardians. The paper analyzes the fault detection, isolation and mitigation mechanisms of each central device based on available documentation and specifications.