Datapath architecture and technology for large scale ATM switching systems

Datapath architecture and technologies for large scale switching systems are studied. Two main key-factors, the complexity of the functional blocks such as the switch fabric, and the interconnection between the functional blocks should be considered. This paper mainly focuses on the interconnection, which is the most important issue to be resolved before achieving a practical multi-hundreds-Gbps switching system. The complexity of the switch fabric would not be the constraints considering the progress of very large scale integrated circuit (VLSI) technology, which allows more than one-mega gates on a chip. Many aspects of interconnection technologies have been investigated including switch fabric functional allocation to functional blocks, datapath width expansion between VLSI chips or shelves, and high-speed transmission utilizing CMOS and optical technologies. This paper also shows a single card ATM unit switch with a throughput of 20-Gbps as an example of the feasibility of these technologies.