Using a Single Switch with O(M) Inputs/Outputs for the Construction of an Optical Priority Queue with O(M3) Buffer

In this paper, we consider the construction of an optical priority queue with a single (M + 1) × (M + 1) switch and M fiber delay lines. The M fiber delay lines are connected from M outputs of the switch back to M inputs of the switch, leaving one input (resp. output) of the switch for the input (resp. output) of the priority queue. It was known in [8][9] that with an appropriate choice of the lengths of the delay lines, such a construction can be used for exact emulation of an optical priority queue with O(M) buffer size. In this paper, we show that the buffer size can be further extended to O(M) using the same construction. The improvement relies on establishing a partial ordering for all the packets stored in the delay lines.