Priority scheduling in switched industrial Ethernet

Switched Ethernet is increasingly advocated as a solution for industrial communication. One typical requirement in such fields is the need to guarantee deterministic transfer delay for cyclic control data, but traditional Ethernet communication does not provide priority feature for industrial data transfer. To address this problem, the IEEE 802.1p queuing feature is introduced into both Ethernet switches and communication nodes to give real-time data, especially cyclic control data the priority to access network resources. On the other hand, it is necessary to provide different priority services for real-time data with different urgencies, so EDF (earliest deadline first) queuing is also introduced to real-time data queues to provide this feature. Finally the effectiveness of these priority-scheduling methods is verified by a network simulation using OPNET modeler.