History of the Internet

Mini Tutorial

Internet for You

Katarzyna J. Macura, M.D., Ph.D.

The Russell H. Morgan Department of Radiology and Radiological Science • Johns Hopkins Medical Institutions

Part 1 — History of the Internet
by Katarzyna J. Macura, M.D., Ph.D.

In 1957, the U.S.S.R. launched Sputnik, the first artificial earth satellite. The Sputnik missions happened during the midst of the Cold War between the U.S.S.R. and the United States. In response, the U.S. government made the space technology a national priority and formed the Advanced Research Projects Agency (ARPA), a segment of the Department of Defense (DoD) charged with ensuring U.S. leadership in science and technology with military applications. The DoD wanted to create a computer network that would continue to function in the event of a disaster, such as a nuclear war. If part of the network were damaged or destroyed, the rest of the system still had to work.

In late 1960s, researchers began working on an experiment to determine whether computers at different universities could communicate with each other without a central system. The corporation Bolt, Baranek and Newman (BBN) had been awarded the contract to develop the Interface Message Processor (IMP), the basis of the new communications system. IMPs would use a technology called packet switching, which split large sections of data into small parts called packets, each labeled with its destination address. Packets could be sent in any order and through different routes which all led to the same destination. Upon arrival at the destination computer, the packets could be reassembled.

In a traditional centralized approach, all information had to be channeled through one source, processed, and sent off somewhere else. The advantage of the packet-switching system was that it allowed information first to be sent to one place, and if that site was not working or processing too slowly, to be routed, on-the-fly, somewhere else. This concept, called dynamic re-routing, would allow all hosts to be "equal." With every computer having the same routing abilities, an enemy would have to destroy nearly all computers on the network to be sure that communication lines were dead.

In 1969, ARPA built an experimental computer network called the ARPAnet. It tied together military researchers and universities, allowing their computer resources to be shared. The network design was based on open and decentralized architecture utilizing packet-switching technology. A variety of computer hardware could run on it. It was the predecessor of today's Internet. ARPAnet initially connected major computers at the University of California at Los Angeles, the University of California at Santa Barbara, Stanford Research Institute, and the University of Utah, which performed the first packet-switching experiments.

The Birth of TCP/IP

Within a couple of years, several other government, educational and research institutions around the country joined the network. Researchers began working on a new protocol, which would be able to handle larger numbers of users, and the Transmission Control Protocol/Internet Protocol (TCP/IP) was born in the mid-1970s. The U.S. government in 1978 accepted this more sophisticated technology, and TCP/IP became the preferred networking tool. Many view January 1, 1983, when the entire ARPAnet was switched over to TCP, as the "official" beginning of the Internet.

During 1983, to provide operational separation, the military broke off from ARPAnet and formed MILnet. DoD continued to run and fund both networks. With time, more networks were emerging. Educational and commercial organizations that didn't fall into ARPA's original charter wanted to use the same packet-switching technologies. In the early 1980s, two large networks formed: CSnet (Computer Science Network), for members of the computer science academic and industrial community, and BITNET (Because It's Time Network), for the general academic community. Other small networks, like ones for space scientists and high-energy physicists grew for specific needs; the latter also helped develop the foundation of the World Wide Web in 1989.

While these networks existed separately from ARPAnet, there was a need for interconnection between all of them. In 1983, CSnet and ARPAnet negotiated an agreement, which allowed members of the two networks to exchange electronic mail. Further agreements followed, and the networks began building gateways between one another. In 1985, the National Science Foundation (NSF) created NSFnet, a series of networks for research and education communication. Based on ARPAnet protocols, the NSFnet created a national backbone service, provided free to any U.S. research and educational institution. At the same time, regional networks were created to link individual institutions with the national backbone service.

NSFnet grew rapidly as people discovered its potential, and as new software applications were created to make access easier. Corporations such as Sprint and MCI began to build their own networks, which they linked to NSFnet. As commercial firms and other regional network providers have taken over the operation of the major Internet arteries, NSF has withdrawn from the backbone business. In 1990, the ARPAnet was decommissioned, leaving the vast network-of-networks called the Internet.

Internet Interest Explodes

From 1989 until 1995, there were few changes in the structure of the Internet, but a mass explosion of interest. The number of hosts was more than doubling in two years. In 1995 the NSFnet was turned off and Internet traffic was handed over to commercial networks. The NSF is still funding research and setting guidelines for network providers, however new infrastructure is built and maintained by offspring of telephone companies and other organizations.

While the United States still leads the world in Internet-based technologies, other nations have developed similar networks, which connect through gateways. The Coordinating Committee for Intercontinental Research Networks (CCIRN) has led the way in bringing the world into internetworking.

Internet 2

The future of the Internet is the Internet2. Formed in 1996 and administered by the University Corporation for Advanced Internet Development (UCAID), Internet2 is a partnership between universities, corporations and government agencies. It's a "laboratory" for networking experiments. The project's goals are to advance the Internet to a new level of efficiency and security for networked communication and robust application development in education and research. Internet2 is a not a single network, but a consortium of hundreds of high-speed networks linked by fiber optic backbones that span the United States and link to other countries. It transmits data at speeds up to 2.4 gigabits per second; over 40,000 times faster than a 56 kilobit per second modem, allowing scientists to test their laboratory discoveries in the real world. The next-generation network went online in 1999, linking a number of universities around the world. It should be offered for commercial use in a few years. When it becomes available, services like interactive television, virtual 3D videoconferencing, movies-on-demand, sharing specialized equipment, and others will be widely available. High-speed networks will make it possible for professionals to work in ways that were never possible before.

Within 30 years, the Internet has grown from a Cold War concept for a command-and-control network in post-nuclear America, to the Information Superhighway. Many don't realize that there is more than a metaphor, which connects the Information Superhighway with the Interstate Highway System.

In 1957, while responding to the threat of the Soviets in general and the success of Sputnik in particular, President Eisenhower created both the Interstate Highway System and the Advanced Research Projects Agency (ARPA). Just as the railroads of the 19th century enabled the Machine Age, and revolutionized the society of the time, the Internet takes us into the Information Age, and greatly affects the world in which we live.

Brief history of the Internet: http://www.isoc.org/internet-history/brief.html

Internet Timeline: http://www.zakon.org/robert/internet/timeline/

www.aawr.org