Cost vs capacity analysis of non-blocking ATM switching networks composed of ATM switching modules

Structures of multistage non-blocking networks composed of ATM switching modules (ASM) are described. The condition under which the network will be non-blacking is formulated, and the relationship between the maximal capacity of the network and the number of switching stages is discussed. Formulas for designing optimal three-stage network is derived. In this document ASM will be considered as a black box in which information can be transferred from any channel of any incoming grouped link into any outgoing grouped link. In other words, within the ASM module each incoming signal is destined only to a output grouped link, not destined to a single outgoing channel. Therefore, the number of cross-points within an ASM is reduced by the factor of the group size. The cost (in terms of lasers and cross-points) of achieving a low latency output queued structure with minimal buffering is quantified