EDF-Based Real-Time Message Scheduling of Periodic Messages on a Master-Slave-Based Synchronized Switched Ethernet

Switched Ethernet has many features for real-time communications but cannot guarantee the timely delivery of a real-time message due to possible collisions on the output ports. This paper first suggests a feasible condition for real-time communication of periodic messages on a master-slave-based synchronized switched Ethernet. Then an EDF (Earliest Deadline First)-based scheduling algorithm that satisfies the proposed scheduling condition is proposed. The master node checks the feasible condition for messages and makes a message transmission schedule for feasible messages. The proposed scheduling algorithm can handle dynamic message requests and performs the real-time communication without any modification in the switch. The performance of the proposed scheduling algorithm has been evaluated by simulation to show the timely delivery of real-time messages and the real-time communication capacity of the switched Ethernet.