Switched Real-Time Ethernet with Earliest Deadline First Scheduling—Protocols, Trafic Handling and Simuation Analysis


H. Hoang
M. Jonsson
U. Hagstorm
A. Kallerdahl


There is a strong interest of using the cheap and simple Ethernet technology for industrial and embedded systems. This far, however, the lack of real-time services has prevented this change of used network technology. This paper presents enhancements to full-duplex switched Ethernet for the ability of giving throughput and delay guarantees. The switch and the end-nodes controls the real-time tra.c with Earliest Deadline First (EDF) scheduling on the frame level. No modi.cation to the Ethernet standard is needed in the network that supports both real-time and nonreal- time TCP/IP communication. The switch is responsible for admission control where feasibility analysis is made for each link between source and destination. The switch broadcasts Ethernet frames regularly to clock synchronize the end nodes and to implement .ow control for non-real-time tra.c. We have characterized the performance of the network in terms of channel acceptance ratio by simulations with di.erent number of nodes connected to the switch.


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