Research On Real-time Performance Of Network Control System Based On Industrial Ethernet

With the rapid development of network control technology, industrial Ethernet is used in auto-control fields. However, the real-time problem is still the main obstacle in applications to network control system based on Ethernet. To break through the real-time researches on Ethernet, this topic chooses the switched Ethernet as main object, studies and improves the IEEE802.1p priority scheduling protocol.The paper starts from the analysis of the whole delay of network control system based on Ethernet, studies the network derivational delay and the industrial Ethernet delay and makes sure that the switched Ethernet is the main studied object. In view of the interior queuing delay in switches using IEEE802.1p priority scheduling protocol, the paper presents the scheduling improved idea and gives a scheme. To further study on the performances of network delay in improved IEEE802.1p priority scheduling protocol, the paper designs a typical switched Ethernet model with tree topology, calculates the maximum delay of periodic real-time data in every transmitted part and derives the base conditions in improved priority scheduling protocol. Lastly, the paper validates the feasibility and validity which the improved IEEE802.1p priority scheduling protocol can decrease the maximum network delays in switched Ethernet.The results of Network calculus and OPNET simulation show that the suitable improvement of IEEE802.1p priority scheduling protocol can improve the real-time performances of hard real-time data transmitted in the switched Ethernet.