The Origin of the Internet

The ancestor of the Internet was the ARPANET, a project funded by the Department of Defense (DOD) in 1969, both as an experiment in reliable networking and to link DOD and military research contractors, including the large number of universities doing military-funded research. ARPA stand for Advanced Research Projects Administration, the branch of Defense in charge of handing out grant money. For enhanced confusion, the agency is now known ad DARPA, the added D is for Defense, just in case there was any doubt where the money was coming from. The ARPANET started small, connecting 3 computers in CA with one in Utah, but it quickly grew to span the continent.

The reliable networking part involved dynamic routing. If one of the network links became disrupted by enemy attack, the traffic on it could automatically be rerouted to other links.

The ARPANET was wildly successful, and every university in the country wanted to sign up. This success meant that the ARPANET began getting difficult to manage, particularly with the large and growing number of university sites on it. So it was broken into 2 parts: MILNET, which had the military sites, and the new, smaller ARPANET, which had the nonmilitary sites. The two networks remained connected, however, thanks to a technical scheme called IP (Internet Protocol), which enabled traffic to be routed from one network to another as necessary. All the networks connected in the Internet speak IP, so they all can exchange messages.

Although there were only 2 networks at that time, IP was designed to all for tens of thousands of networks. An unusual fact about the IP design is that every computer in an IP network is, in principle, just a capable and any other, so ay machine can communicate with any other machine. This communication scheme may seem obvious, but at the time most networks consisted of a small number of enormous central computers and a large number of remote terminals, which could communicate only with the central systems, not with other terminals.

Berkeley and UNIX

Beginning around the 1980, university computing was moving from a small number of large time-sharing machines, each of which served hundreds of simultaneous users, to a large number of smaller desktop workstations for individual users. Because users had gotten used to the advantages of time-sharing systems, such as shared directories of files and e-mail, they wanted to keep those same facilities on their workstations.

Most of the new workstations ran a variety of UNIX, an OS that had been developed at ATandT and the University of CA Berkeley. The people at Berkeley were big fans of computer networking, so their version of UNIX included all the software necessary to hook up to a network. Workstation manufactures began to include the necessary network hardware also, so all you had to do to get a working network was to string the cable to connect the workstations.

Then, rather than have one or two computers to attack to the ARPANET, a site would have hundreds. What's more, because each workstation was considerably faster than entire the 1970s multi-user system, one workstation could generate enough network traffic to swamp the AEPANET, which was getting creakier by the minute. Something had to give.

National Science Foundation

The next event was the National Science Foundation (NSF) decided to set up 5 supercomputers, a really fast computer, centers for research use. The NSF figured that it would fund a few supercomputers, let researchers from all over the country use the ARPANET to send their programs to be "supercomputer," and then send back the results.

The Plan to use the ARPANET didn't work out for a variety of reasons, some technical and political. So the NSF, never shy about establishing a new political empire, built its own network to connect the supercomputing centers: the NSFNET. Then it arranged to set up a bunch of regional networks to connect the users in each region, with the NSFNET connecting all the regional networks.

The NSFNET worked like a charm. By 1990, in fact, so much business had moved from the ARPNET to the NSFNET that, after 20 years, the ARPANET had outlived its usefulness and was shut down. The supercomputer centers the NSFNET was supposed to support turned out to be a fizzle: some of the supercomputers didn't work, and the ones that did were so expensive to use that most potential customers decided that a few high-performance workstations would serve their need just as well. Fortunately, by the time it became clear that the supercomputers were on the way out, the NSFNET had become so fixed in the Internet that it lived on without its original purpose. By 1994, several large, commercial Internet networks had grown up within the Internet, some run by large, familiar organizations such as IBM and Sprint and others by such specialist Internet companies as Performance Systems International (aka PSI) and Alternet. The NSFNET has been wound down, with its traffic taken over by commercial networks.

The NSFNET permitted traffic related only to research and education, but the independent, commercial IP network services can be used for other kinds of traffic. The commercial networks connect to the regional networks just like the NSFNET does, and they provide direct connections for customers.

Outside the US, IP networks have appeared in many countries, either sponsored by the local telephone company or run by independent national or regional providers. The first international connections were in 1973 with England and Norway. Nearly all countries are connected directly or indirectly to some US network, meaning that they all can exchange traffic with each other.

The term Internet first appeared in 1982 with DARPA's launch of the Internet Protocol, IP.

Source: The internet for Dummies, 3rd edition. Authors: John R. Levine, Carol Baroudi, and Mary Levine Young. Published by: IDG Books Worldwide, Inc. 1995