Experimental determination of network quality of service in Ethernet: UDP, OPC, and VPN

Abstract

As network speeds continue to increase, the delays at the application layers can become more important than the delays on the network. These delays can be significant for control system applications, but are not often specified. Network protocol standards are often more focused on transmission reliability and correctness than on transmission delays. For many control system applications, timeliness is more important than accuracy. Recognizing the importance of the application-layer delays, this paper presents the results of a series of experiments on the quality of service in Ethernet networks. For UDP, OPC, and VPN communications, the end-to-end time delays are measured and characterized. The different factors that contribute to the delays are discussed. The paper concludes with some comments on future research directions