On the limits of electronic ATM switching

This article discusses the principal advantages and limitations of electronic switching in asynchronous transfer mode (ATM) networks. Key design parameters of ATM switch implementations are defined, and their relationships with respect to performance, complexity, and cost are modeled and discussed. Design and implementation experience is reported on a very high-performance four-input, four-output ATM switch that has been designed as part of the DARPA-sponsored "Thunder and Lightning" project at the University of California, Santa Barbara. This research project is focused on the design and prototype demonstration of ATM links and electronic switches operating at 40 Gb/s per link (TDM), with potential scalability to 100 Gb/s. Such aggressive link rates are near the implementation limits for electronic ATM switches; they place severe requirements on switch architecture, particularly the buffering scheme.