A parallel-tree switch architecture for ATM networks

We present a novel ATM switch called parallel-tree Banyan switch fabric (PTBSF) that consists of parallel Banyans arranged in a tree topology. Packets enter at the topmost Banyan. Internal conflicts are eliminated by using a conflict free 3/spl times/4 switching element which distributes conflicting cells over different Banyans. Thus, cell loss may occur only at the lowest Banyan. Increasing the number of Banyans leads to noticeable decrease in the cell loss rate. The switch can be engineered to provide arbitrarily high throughput and low cell loss rate without the use of input buffering nor cell pre-processing. The performance of the switch is evaluated analytically under uniform traffic load and by simulation under a variety of ATM traffic loads. Compared to other proposed architectures, the switch exhibited stable and excellent performance with respect to cell loss and switching delay for all studied conditions as required by ATM traffic sources. The advantages of PTBF are modularity, regularity, self-routing, low processing over head, high throughput and robustness under a variety of ATM traffic conditions.