Real-time communication in plant-monitoring/controlling systems with ATM networks

We propose a method for a schedulability check in ATM networks which provide fixed prioritized virtual connections. Our method does not need any run-time scheduling other than fixed priority scheduling at each output link of all switch nodes and traffic shaping at each output link of cell terminal nodes in a network. Rate monotonic analysis assumes a critical instance in which all tasks arrive at the same time. We, however, can obtain information on the times when messages arrive at switch nodes in a network. Using such information, our method can check the schedulability of a set of channels more exactly than the method assuming a critical instance.