Computer Science Network

CSNET (the "Computer Science Network") was funded by the U.S. National Science Foundation in the early 1980s (the initial contract was for the three-year period 1981-1984) with leadership by Larry Landweber (University of Wisconsin), David J. Farber (University of Delaware), Peter Denning (Purdue University), and Douglas Comer (Purdue University). Rand Corporation was the fourth institution involved in the project. CSNET was a computer network linking academic Computer Science departments nationwide.

The CSNET project had three primary components: the Phonenet mail system (Delaware), a name server (Wisconsin), and a TCP/IP-over-X.25 tunnel (Purdue). It was intended as an extension to ARPANET, to which many Computer Science departments didn't have the privilege of access. CSNET connected with ARPANET using TCP/IP, and ran TCP/IP over X.25, but it also supported departments without sophisticated network connections, using automated dial-up mail exchange. Phonenet allowed an institution to have Unix mail services with the underlying transport mechanism being a loosely-connected phone relay network. The name server allowed manual and automated email address lookup based on a variety of attributes of a user (e.g., name, title, institution, etc.). The X.25 tunneling allowed an institution to connect directly to the ARPANET via a commercial X.25 service (e.g., Telenet), where the institution's TCP/IP traffic would be tunneled through to a CSNET machine that would act as a relay between the ARPANET and the commercial X.25 networks. CSNET was developed on DEC VAX 11/750 and 11/780 systems using BSD Unix, but it grew to support a variety of hardware and OS platforms.

CSNET was a forerunner to NSFNet. It operated autonomously until 1989, when it merged with Bitnet to form CREN. By 1991 the growth of the Internet had made the CSNET services redundant, and CREN discontinued them.