In the last 20 years, autonomous decentralized systems (ADSs) have been developed, and now several hundred systems are in effective operation. As the ADS innovates the system concept, new system architectures and technologies have been induced to develop for increasing the merits and decreasing the demerits of ADSs. In this paper, two typical application systems are shown in order to describe the problems, the solutions and the further work required for realizing ADSs. These experiences teach us about the future of ADSs, which are heading towards telecommunications-based information service systems in which end users autonomously select the service they wish to utilize. The research and development for next-generation ADS technologies in telecommunications-based information services will be accomplished through world-wide cooperation.

An asynchronous transfer mode (ATM) switch architecture called a shared buffer memory switch whose output cell buffers are shared among all the output ports of the switch is proposed. Experimental measurements and a discussion about the traffic characteristics of the switch architecture are carried out to determine how much buffer memory will be reduced through buffer sharing under various traffic conditions and to roughly estimate how many buffers are needed for the switch to meet certain requirements. The resultant estimate shows that buffer sharing reduces the necessary buffer memory to less than 1/5 of what would otherwise be required, and the required buffer size is about 128 cells/output for a 32*32 switch when considering bursty traffic conditions. LSI implementation is also discussed to show that a 32*32 switch can be composed of about 12 chips mounted on one printed board.>