Interrupt based Switching for Multi-Cluster FlexRay Systems

This paper deals with a new straightforward approach to significantly increase the bandwidth usage in FlexRay networks. We propose a new hardware component, termed FlexWay, that facilitates partitioning the network into multiple clusters. This component provides a switching service that enables the execution of synchronous communications inside each cluster. Further, it is in compliance with the FlexRay protocol specification v2.1 as no change at the protocol layer is required. We place a great deal of emphasis on minimizing the inter-frame gap regarding the new topology and the proposed switching mechanism which is based on interrupts. Furthermore, we describe how FlexWay improves the fault-tolerance of the whole system by limiting the impact of babbling idiot and short circuit failures. Various experiments, carried out for an example system, show that all nodes keep their local clocks synchronized even in presence of a single failure and that the proposed approach perceptibly increases both the band width and the safety.