Queue Prediction: an efficient scheduler for fast ATM cell transmission

A central problem in ATM switches is the selection of cells to be transmitted on an output line. In general each line has a number of queues, all of which must be handled in a timely manner to provide throughput for each circuit and guarantee its required quality of service. While the problem of the queuing disciplines has been addressed, many of the solutions are computationally complex and appear to be difficult, if not impossible within the time constraints of fast ATM transmission (622 Mbps or higher). This paper presents a solution to this problem. By scheduling in advance the transmissions from queues it allows all output queues for a line to be serviced with minimal overhead and with timings appropriate to each specific queue. Desirable queuing strategies follow automatically as a consequence of the scheduling mechanism. The mechanism appears to be capable of handling many queues (hundreds or thousands) for each output line. A mechanism is proposed for the efficient handling of Variable Bit Rate, time critical traffic. K e y w o r d s ATM cell transmission, queue management, Queue Prediction scheduling