Clos-Knockout: a large-scale modular multicast ATM switch

A large-scale modular multicast ATM switch based three-stage Clos network architecture is proposed and its performance is studied. Although it is a multipath network, the cell sequence is preserved because only output buffers are used in this architecture. The proposed multicast switch has the following advantages: (1) it is modular and suitable for large scale deployment; (2) no dedicated copy network is required since copying and switching are performed simultaneously; (3) two-stage packet replication is used which gives a maximum fan-out of n ²; (4) translation tables are distributive which gives manageable table sizes; (5) high throughput performance for both uniform and nonuniform input traffic; and (6) a self-routing scheme is used. An analytical model for the switch under uniform input traffic is studied and numerical examples demonstrate that the cell loss probability is very small when the expansion ratio is properly chosen