Abstract:

To schedule the messages transmission over master-slave-based multi-switch Ethernet and meet the realtime requirements, we propose a method for calculating the arrival time of the messages scheduled in each elementary cycle to the switch output. In addition, we also present a novel feasibility analysis algorithm called ECSchedTest f for periodic realtime messages scheduled in one elementary cycle, and prove its correctness. Moreover, an EDF-based realtime scheduling algorithm and an admission control algorithm for periodic messages are presented to take full advantage of multiple transmission paths of the switched network. In every elementary cycle, by calculating the time of each message's arrival to the output ports of the switches that it traverses, and considering the FCFS message scheduling policy used in the switch, the scheduler with ECSchedTest  can handle the message transmission precisely and efficiently. Simulation results show the advantages of the proposed real-time scheduling algorithm in terms of the network bandwidth utilization, thus enhancing real-time communication over a master-slave-based multi-switch Ethernet.

Key words: master-slaver-based switched Ethernet；EDF-based scheduling algorithm；real-time periodic message;elementary cycle