An Approach to the Synchronization of Backup Masters in Dynamic Master-Slave Systems

This paper considers the case in which master-slave fieldbus networks are used in safety-critical embedded applications, such as transportation systems. The communication in these networks is controlled by the master that contains a cyclic traffic dispatching table. Master replication is used to achieve fault-tolerance. Traditional approaches to system design, also due to faulttolerance reasons, have considered static tables, only. However, there is a growing demand for flexibility, mainly to improve the efficiency in using system resources. This calls for the replacement of such static tables with dynamic tables, containing the current communication requirements, and for on-line traffic scheduling. This paper considers such dynamic master-slave architectures and addresses the problem of synchronizing the active and backup masters. In particular, the master node uses a scheduling co-processor to speed up the traffic on-line scheduling and schedulability analysis, as well as to achieve synchronization in a short period of time.