Soft Real-Time Guarantee for Control Applications Using Both Measurement and Analytical Techniques

In this paper, we present a probabilistic admission control algorithm over switched Ethernet to support soft real-time control applications with heterogeneous periodic flows. Our approach is purely end host based, and it enables real-time application-to-application QoS management over switched Ethernet without sophisticated packet scheduling or resource reservation mechanisms in Ethernet switches or middleware on end hosts. In designing the probabilistic admission control algorithm, we employ both measurement and analytical techniques. In particular, we provide a new and efficient method to identify and estimate the queueing delay probability inside Ethernet switches for heterogeneous periodic flows with variable message sizes and periods. We implemented the probabilistic admission control algorithm on the Windows operating system, and validated its efficacy through extensive experiments.