We propose an efficient multicast cell-scheduling algorithm, railed multipl
e-slot cell-scheduling algorithm, for multicast ATM switching systems with
input queues. Cells in an input-queueing system are usually served based on
the first-in-first-out (FIFO) discipline, which may have a serious head-of
-line (HOL) blocking problem, Our algorithm differs from previous algorithm
s in that we consider the output contention resolution for multiple time sl
ots instead of the current time slot only. Like window-based scheduling alg
orithm, our algorithm allows cells behind an HOL cell to be transmitted pri
or to the HOL cell in the same input port. Thus, HOL blocking can he allevi
ated, We have illustrated that the delay-throughput performance of our algo
rithm outperforms most of those algorithms that consider only the output co
ntention resolution for the current time slot. We also present a simple and
efficient architecture for realizing our algorithm, which can dramatically
reduce the time complexity, Wt believe that the proposed architecture is v
ery suitable for multicast asynchronous transfer mode (ATM) switching syste
ms with input queues.