Classification of Activated Faults in the FlexRay-Based Networks

FlexRay communication protocol is expected to become the de-facto standard for distributed safety-critical systems. This paper classifies the effects of transient single bit-flip fault injections into the FlexRay communication controller. In this protocol, when an injected fault is activated, this may result in one or more error types, i.e.: Boundary violation, Conflict, Content, Freeze, Synchronization, Syntax, and Invalid frame. To study the activated faults, a FlexRay bus network, composed of four nodes, was modeled by Verilog HDL; and a total of 135,600 transient faults was injected in only one node, called the target node. The results show that only 9,342 of the faults (about 6.9%) were activated and their effects were observed in the network nodes. The results also show that the Synchronization error is the widespread error with the occurrence rate of 70.1%. The Invalid frame, Boundary violation, Syntax, Content, Freeze, and Conflict errors have the occurrence rates of 51.1%, 32.4%, 24.6%, 20.6%, 17.3%, and 0.0%, respectively. Among the error types, the Freeze errors are the most critical errors as they mostly result in system failures. The results also show that most of the activated faults, about 75.3%, were observed simultaneously in the target node and a neighbor node. About 11.1% of the activated faults were observed only in the target node and about 13.5% only in the neighbor node.