A recursive modular terabit/second ATM switch

The author proposes a recursive modular architecture for a very large scale asynchronous transfer mode (ATM) switch. By extending the concept of the original knockout switch, the cell filtering and contention resolution functions are distributed over many small switch elements, which are arranged in a crossbar structure. The output ports of a switch fabric are partitioned into a number of groups by a novel grouping network to permit sharing of the routing paths in the same group. This partitioning and sharing concept is applied recursively to construct the entire switch elements. The technique of channel grouping for trunk circuits can be incorporated in the proposed ATM switch to improve the cell loss/delay performance while the cells´ sequences are retained. A prototype circuit for the key switch element has been designed, and it has been shown that more than 4000 of the switch elements can be integrated into a VLSI chip with existing CMOS 1-μm technology