The paper is focused on the architectural and technological solutions that will allow the transition from small to huge capacity ATM Switching Systems. This path starts from the industrial nodes available today and will arrive at the photonic switching architecture. The progressive introduction of photonics has already started with the use of optical interconnections in ATM nodes of hundreds of Gbit/s. A balanced use of microelectronics and photonics is the correct answer to the Terabit/s switching system challenge. After presenting a modular ATM Switching System, some technological solutions like Multichip Modules and Optical Interconnections are presented in order to explain how node capacity can be expanded. Some results of the research activity on photonic Switching are finally shown in order to exploit the great attitude of this technique to obtain very high throughput nodes.