Switched Real-Time Ethernet for Industrial Applications

Sammanfattning: The research reported in this thesis has been focused on developing and analyzing how to support real-time traffic over a switched Ethernet network without any hardware or protocol modifications. The work has resulted in a proposed systems model, supporting both real-time and non real-time traffic. Currently this model is intended for a one-switch network, with no shared media. All added traffic handling to support real-time communication is positioned in a thin layer (RT layer) added between the Ethernet layer and the TCP/IP suite. This assures adaptation to the surrounding protocol standards. The RT layer manages traffic on the basis of virtual connections, denoted as RT channels, as well as packet level scheduling. RT channels are created between end-nodes prior to any occurrence of real-time traffic. Asymmetric deadline partitioning between the links of the RT channels is also proposed, in order to increase the number of possible RT channels.