32×32 shared buffer type ATM switch VLSIs for B-ISDNs

A set of 0.8 μm CMOS VLSIs developed for shared buffer switches in asynchronous transfer mode (ATM) switching systems is described. A 32×32 unit switch consists of eight buffer memory VLSIs, two memory control VLSIs, and two commercially available first in first out (FIFO) memory LSIs. Using the VLSIs, the switch can be mounted on a printed board. To provide excellent traffic characteristics not only under random traffic conditions but also under burst traffic conditions, this switch has a 2-Mb shared buffer memory, the largest reported to date. which can save 4096 cells among 32 output ports. This switch has a priority control function to meet the different cell loss rate requirements and switching delay requirements of different service classes. A multicast function and a 600 Mb/s link switch architecture, which are suitable for ATM network systems connecting various media, and an expansion method using the 32×32 switching board to achieve large-scale switching systems such as 256×256 or 1024×1024 switches are discussed