1985

NSFNET

ARPANET was a restrictive club. The precursor to today’s internet, ARPANET was open only open to organizations directly supporting the US Department of Defense (DOD), which was picking up the bill. Expanding the club meant expanding the funding base. The US National Science Foundation (NSF) did just that in 1980, when it gave a consortium of universities $5 million to create the Computer Science Network (CSNET), and again in 1985, when it commissioned the National Science Foundation Network (NSFNET). The networks interconnected at universities that had both DOD and NSF contracts.

CSNET featured a mix of technologies with the short-term goal of providing computer science departments with email and limited-access remote terminal capability. The number of hosts jumped from three in 1981 to 24 in 1982 and 84 in 1984. But the network’s fundamental goal was to get its academic members access to the ARPANET so they could exchange email and use the other resources.

NSFNET had the much broader goal of creating a nationwide network—and, in particular, providing researchers around the US with access to the NSF’s five supercomputing centers. The original NSFNET went live in 1986 with seven 56-kilobit-per-second links—and they were almost immediately saturated. In 1988, the network was expanded to 13 nodes interconnected by 1.5-megabit-per-second T1 links. Within three years, those T1 links were upgraded to 45-megabit-per-second T3 links. By that point, NSFNET linked 3,500 networks at 16 sites. Few users noticed when ARPANET was shut down on February 28, 1990—the non-Defense users had all migrated.

While NSFNET could purchase faster network links, there was no hardware or software that could run at such speeds. “No one had ever built a T3 network before,” said Allan Weis, president of Advanced Network and Services, Inc., the nonprofit created to manage the network, as reported in the NSFNET final report. It took years of work before the T3s were running at full speed.

But while NSFNET greatly improved access to the internet, it also had an “acceptable use policy” that limited the use of the network to the support of research and education—and prohibited commercial ventures.

A visualization study of inbound traffic measured in billions of bytes on the NSFNET T1 backbone for the month of September 1991, ranging from purple (0 bytes) to white (100 billion bytes).