Deterministic performance bounds in a window-based token ring network supporting two priorities

A window-based token ring protocol supporting two priority traffic streams is proposed. This protocol uses the window timers to limit the packet transmissions of a token holding station. The packets arriving during a window period are always transmitted before those arriving during subsequent window periods. Nonpreemptive priority service discipline is used to serve high priority packets. A call admission control policy based on delay bound is then employed to guarantee QoS such as the packet delay, delay jitter, and the packet loss-free requirement for both priority traffic streams. Under such window-based token ring operation and call admission control, network-wide fairness can be achieved and the network output traffic characteristics become predictable. With these properties, we would expect that the window-based token protocol is more appropriate for real-time communications.