Queueing in space-division packet switching

The authors study the performance of four different approaches for providing the queuing necessary to smooth fluctuations in packet arrivals to a space-division packet switch. They are (1) input queueing, where a separate first-in, first-out (FIFO) buffer is provided at each input to switch; (2) input smoothing, where a frame of b packets is stored at each of the N input lines to the switch and simultaneously launched into a switch fabric of size Nb*Nb; (3) output queuing, where packets are queued in a separate FIFO buffer located at each output of the switch; and (4) completely shared buffering, where all queuing is done at the outputs and all buffers are completely shared among all the output lines.<>