Abstract: A growable ATM switch architecture is desired for constructing a large scale ATM switch. All the current ATM switch architectures are based on uniform connections of unit switch elements. When the switch size becomes large, the uniform switch architecture is no longer suitable for the nonuniform traffic conditions. In this paper, we propose a nonuniform modular growth ATM switch architecture by using a knockout switch as the basic unit. All the internal traffic of the proposed switch has the best delay and throughput performance. An analysis is also presented to study the relationship between the cell-loss performance and the switch parameters. The knockout principle proves to be very efficient for the nonuniform concentration in the proposed switch architecture. The proposed switch architecture is cost-effective compared with the growable switch architecture which employs the uniform connection pattern.