Weighted round-robin cell multiplexing in a general-purpose ATM switch chip

The authors present the architecture of a general-purpose broadband-ISDN (B-ISDN) switch chip and, in particular, its novel feature: the weighted round-robin cell (packet) multiplexing algorithm and its implementation in hardware. The flow control and buffer management strategies that allow the chip to operate at top performance under congestion are given, and the reason why this multiplexing scheme should be used under those circumstances is explained. The chip architecture and how the key choices were made are discussed. The statistical performance of the switch is analyzed. The critical parts of the chip have been laid out and simulated, thus proving the feasibility of the architecture. Chip sizes of four to ten links with link throughput of 0.5 to 1 Gb/s and with about 1000 virtual circuits per switch have been realized. The results of simulations of the chip are presented