System design and evaluation of a large modular photonic ATM switch

A photonic ATM switching node based on the Fibre Delay Line switching element developed in the framework of the RACE project ATMOS (ATM Optical Switching) is described. The feasibility of this switching element has been proved within the physical limitation of present day technology to support up to 16 input and 16 output lines and a buffer capacity of at least 16 cells for each output. In this paper various interconnection options are discussed with the aim of a large, high throughput switch implementation. In particular a Clos architecture is chosen for the design of a 256 x 256 switching fabric operating at 2.5 Gbit/s and its performance is evaluated by means of simulation in a random and bursty traffic environment. It is demonstrated that a multiplane configuration of optical matrices followed by an efficient concentration strategy is capable of meeting the target ATM requirements, that is cell loss probability less than 10(-9) with load up to 0.8. A detailed design of the switch and its complexity evaluation are also given.