Schedulability analysis for real-time messages over switched Ethernet with EDF scheduling

To overcome the drawback that switched Ethernet can not meet the real-time requirements in industrial communications, an improved message transmission model in which switch and the end-nodes control the real-time traffic with Earliest Deadline First (EDF) scheduling was proposed. In addition, a distributed admission control method for periodic messages which is performed by the source and the destination nodes without the modification of the operational features of Ethernet switch was presented. Moreover, a more general schedulability condition for real-time periodic message over switched Ethernet was given and proved by using real-time scheduling theory.