A gigabit ATM-LAN protocol for multimedia communications

An ATM (asynchronous transfer mode) based MAC (medium access control) protocol for gigabit LAN/MANs is proposed and its performance behavior for various load conditions is evaluated. The main design object of the protocol called HMR (high-speed multimedia ring) is the minimization of medium bandwidth loss by the function of fairness and priority control in the 1 Gbps-times-100 Km class. The effective solution of this object is the multiple window-token algorithm where each priority level has its own window-token for fairness control. In the multiple window-token algorithm, the rotation time of priority k window-token represents the offered load of priority k and higher. If the window-token rotation time of priority k exceeds a given threshold, access units cannot transmit cells of priority lower than k and they hold tokens of priority lower than k. As a result, the maximum access delay can be bounded in a certain range with minimum bandwidth loss whereas the window-token rotation time is kept under a certain value.<>