The IBM Enterprise Systems Connection (ESCON) Director: A dynamic switch for 200Mb/s fiber optic links

This paper describes the function and hardware structure of the Enterprise Systems Connection (ESCON™) Director™, an I/O switch capable of providing dynamic, nonblocking, any-to-any connectivity for up to 60 fiber optic links operating at 200 Mb/s. Optoelectronic conversion at the switch ports allows the switching of the fiber optic links to be done electronically. The establishment of paths in the switching matrix is done by means of a hard-wired, pipelined controller at a maximum rate of five million connections/disconnections per second. Routing information is provided in the header of data frames. The switch-port function, switching matrix, and matrix controller were implemented in the IBM 1-µm CMOS “standard cell” technology. The paper discusses the system interconnection philosophy, details of the data flow, the switch hardware architecture, the design methodology, and the approach to technology implementation.