Switching techniques for packetized data and for video communications are a key element in the evolution of the central office from IDN, to ISDN, and to broadband ISDN. An evolutionary scenario, based both on a short-term and on a longterm reference architecture for the switching system, is proposed, and two advanced switching techniques for labeled switching and for diffusive video switching, respectively, are analyzed which match the above scenario well. Plans and preliminary results are also reported on experimental research through laboratory demonstrators of the two switching techniques.

Digitalization of the Italian telecommunications network is underway, as in many other countries, and a significant diffusion of digital transmission has already been achieved. Digital switching has already been introduced at both transit and local levels, with some 450 exchanges presently in operation. Both packet- and circuit-switched data networks are in operation. CCITT No. 7 is presently being introduced. In this network scenario, the already planned Italian developments towards the ISDN will include the provision in 1986 of 64 kbit/s digital connectivity and, two years later, the activation of a pilot ISDN service, whose main characteristics are described in the paper. An overview on further developments in ISDN research areas is also given.