INTERNET

INTERNET. Arguably the most important communications tool ever created, the Internet connects millions of people to online resources each day. Grown from seeds planted during the Cold War, the roots of the Internet were formed to develop a reliable, national system for communications. Although early pioneers disagree over whether the computer-based communications network was built to withstand nuclear attack, the uneasy tension between the United States and the Soviet Union during the Cold War certainly increased the resolve of the United States to fund and develop relevant scientific and defense-related projects aimed at national security.

Home to many of the preeminent scientists of the time, the Massachusetts Institute of Technology (MIT) served as the birthplace of the Internet. It was there, in Cambridge, Massachusetts, that President Harry Truman's administration formed MIT's Lincoln Laboratories to begin work on the Semi-Automatic Ground Environment. SAGE's primary goal was to develop an air defense system that involved a network of interconnected computers across the United States. The push for advanced technology received an even larger boost in August 1957, when the Soviet Union test fired its first intercontinental ballistic missile and subsequently launched its Sputnik orbiter in October of that same year. Shortly thereafter, President Dwight D. Eisenhower convened a meeting of his Presidential Science Advisory Committee. From that meeting and subsequent congressional testimony on the progress of U.S. defense and missile programs, it became clear that the "science gap" between the two superpowers had widened. Eisenhower sought funding for the Advanced Research Projects Agency (ARPA) late in 1957 and obtained it the following year.

In the early 1960s, the Lincoln Laboratory researchers Lawrence Roberts and Leonard Kleinrock worked on developing a method of digitizing and transmitting information between two computers using a communications method called packet switching. Similar work on systems that used store-and-forward switching was also underway in the late 1950s under the direction of Paul Baran and Donald Davies at the National Physical Laboratory in England. At the heart of both research projects was the development of a communications system in which information would be distributed among all nodes on a network, so that if one or more nodes failed, the entire network would not be disabled. This type of network, in which messages were passed from node to node, with no single node responsible for the end-to-end traffic, was called hot-potato routing.

ARPA's first director, J. C. R. Licklider, moved from Lincoln Laboratory to a small Cambridge, Massachusetts–based consulting firm, Bolt, Beranek, and Newman (BBN), where researchers continued to explore the use of computers as tools of communication. While there, Licklider and his colleagues developed the necessary hardware to connect computers to telephone lines and also researched the collection of data from a wide array of other sources including antennae, submarines, and other real-time sensors. Most of BBN's projects were ARPA supported and sought to achieve ARPA's ultimate goal of helping close the science gap by creating a nationwide network of interconnected computers.

In the summer of 1968, ARPA issued a request for proposals to more than 130 different research centers with the goal of creating a digital network of computers conforming to ARPA's technical specifications. Roberts developed the criteria and served as the chief architect of the network's overall design, which included the deployment of "packet switching technology, using half-second response time, with measurement capability, and continuous operation"—that is, an Internet. Frank Heart and the team of scientists at BBN were awarded the contract in December 1968.Outfitted with specialized minicomputers and interface hardware, BBN set out to connect their "packet switches" or Interface Message Processors

(IMPs), at each ARPA-determined remote location (node), which would then communicate with the host computer at that location. Robert Kahn and Vincent Cerf, with Jon Postel and Charles Kline, developed the software to connect host computers to the IMPs, a host-to-host protocol on how packets would be routed. While America was absorbed in NASA's race to land on the moon in the summer of 1969, BBN air shipped its first IMP computer across the country—no small feat for the time. It arrived safely and was working at the first node, the University of California at Los Angeles, in August 1969.

This phase of the ARPA-BBN project was completed in nine months. Meanwhile, work continued on equipping the second node, the Stanford Research Institute (SRI) in Palo Alto—some four hundred miles away—to the interface message processor. On 1 October 1969 the Stanford node came online and the first message, "LO," was passed that day. BBN continued to progress, installing nodes three and four at the University of California at Santa Barbara (1 November 1969) and the University of Utah (1 December 1969).Only in March of the following year did BBN connect its Cambridge offices to the newly created ARPAnet.

The ARPAnet continued to evolve through the early 1970s with the addition of more diverse data networks such as the University of Hawaii's ALOHAnet packet radio network and the European-based packet satellite network. During this period, the first terminal interface processor (TIP) was introduced to the network, thereby allowing computer terminals to call directly into the ARPAnet using standard telephone lines. In 1972, the first electronic messaging program (e-mail) that supported incoming and outgoing messages was developed. In that same year, a file transfer protocol specification (FTP) to allow for the transmission of data files across the network was designed and tested. With these additions, ARPAnet truly began to fulfill its mission as an open-architecture network, accommodating a variety of different environments and allowing the free sharing of resources.

As the uses of the network grew, more efficient methods for carrying data were needed, forcing an evolution of transmission protocols—the underlying control layer in which the messages flowed—and addressing schemes. After many refinements, TCP/IP (transmission control protocol/Internet protocol) became the de facto standard for communicating on the network. A naming scheme also became necessary and the Domain Name System (DNS) was developed by Paul Mockapetris of the University of Southern California. DNS allowed for the assignment of names to networks and nodes, supplanting the use of numeric addresses. In 1973, Ethernet technology was developed, allowing for the rapid addition of nodes and workstations to the network. With the birth of the personal computer and local area networks (LANs) in the early 1980s, the network grew at a staggering pace.

The federal government funded the network and its infrastructure through 1995.The work of the National Science Foundation (NSF) was instrumental for under-standing the future evolution of the Internet as a true "information superhighway." However, federal funding of the Internet was terminated as a result of the NSF's privatization initiative to encourage commercial network traffic. Control of the large backbones of the network—the set of paths with which local or regional networks connected for long-haul connectivity—was redistributed to private regional network service providers.

The Internet serves as a vital network of communication in the form of e-mail, news groups, and chat. It also provides unparalleled resource sharing and resource discovery through the World Wide Web. At the end of 2001, the Internet continued its phenomenal annual rate of growth of 100 percent. At its start in 1981, the Internet connected just over two hundred researchers and scientists. By the end of 2002, it is estimated that the Internet had the capacity to reach more than six billion people worldwide.

INTERNET

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