Nonblocking ATM switching networks composed of ATM switching modules

A way of interconnecting output queued ATM switching modules together as a Clos-like architecture to build very large ATM switching networks is proposed. Switching modules can be electronic or free-space photonic based ATM switches but, these should be generalised knockout switches with output queued modules. These make use of output grouping, which also minimises the number of fibre optic interconnections required. This approach takes advantage of internal speed-up within the modest size ATM switching modules as well as the external speed-up at the output of these switching modules. Both analytical and computer simulation techniques are used to assess the performance of the proposed switching network.