History of Internet

The Internet is not a recent development but an idea that has been aroundfor more than 45 years. The concept first took shape during the early and mid-1960s and was based on the work of computer scientists at MIT and the RAND Corporation in the United States and the NPL Research Laboratory in Great Britain. The first proposal for building a computer network was made by J. C. R. Licklider of MIT in August 1962. He wrote his colleagues a memo titled (somewhat dramatically) “The Galactic Network,” in which he described a globally interconnected set of computers through which everyone could access data and software.

In 1966, Roberts moved to the Advanced Research Projects Agency(ARPA), a small research office of the Department of Defense charged with developing technology that could be of use to the U.S. military. ARPA was interested in packet-switched networking because it seemed to be a more secure form of communications during wartime.

ARPA funded a number of network-related research projects, and in1967 Roberts presented the first research paper describing ARPA’s plans to build a wide area packet-switched computer network. For the next twoyears, work proceeded on the design of the network hardware and software.The first two nodes of this new network, called the ARPANET, were constructed at UCLA and the Stanford Research Institute (SRI), and in October 1969, the first computer-to-computer network message was sent. Later that same year two more nodes were added (the University of California-Santa Barbara and the University of Utah), and by the end of 1969, the buddingfour-node network was off the ground.

The success of the ARPANET in the 1970s led other researchers to develop similar types of computer networks to support information exchange withintheir own specific scientific area: HEPNet (High Energy Physics Network),CSNET (Computer Science Network).

Farsighted researchers at ARPA, in particular Robert Kahn, realized that this rapid and unplanned proliferation of independent networks would lead to incompatibilities and prevent users on different networks from communicating with each other, a situation that brings to mind the problems that national railway systems have sharing railcars because of their use of a different gauge track. Kahn knew that to obtain maximum benefits from this new technology, all networks would need to communicate in a standardized fashion. He developed the concept of internetworking, which stated that any WAN is free to do whatever it wants infernally. However, at the point where two networks meet, both must use a common addressing scheme and identical protocols—that is, they must speak the same language.

Figure 7.21 is a diagram of a “network of networks.” It shows four WANs called A, B, C, and D interconnected by a device called a gateway that makes the internetwork connections and provides routing between different WANS. To allow the four WANs of Figure 7.21 to communicate, Kahn and his colleagues needed to create (1) a standardized way for a node in one WAN to identify a node located in a different WAN and (2) a universally recognized message format for exchanging information across WAN boundaries. 

Kahn and along with Dr. Vinton Cerf of Stanford, began working on these problems in 1973, and together they designed the solutions that became the framework for the Internet. Specifically, they created both the hierarchical host naming scheme that we use today and the TCP/IP protocols that are the “common language” spoken by networks around the world.

During the late 1970s and early 1980s, work proceeded on implementing and installing TCP/IP on not only mainframe computers but also on the PCs and desktop machines that were just starting to appear in the marketplace.It is a tribute to the power and flexibility of the TCP/IP protocols that they were able to adapt to a computing environment quite different from the one that existed when they were first created. Originally designed to work with the large mainframe computers of the 1970s, they were successfully implemented in the modern computing environment—desktop PCs connected by LANs.

By the early 1980s, TCP/IP was being used all around the world. Even networks that internally used other communication protocols implemented TCP/IP to exchange information with nodes outside their own community. At the same time, exciting new applications appeared that were designed to meet the growing needs of the networking community.For example, Telnet is a software package that allows users to log on remotely to another computer and use it as though it were their own local machine.FTP (File Transfer Protocol) provides a way to move files around the network quickly and easily. Along with e-mail (still wildly popular), these and other new applications added more fuel to the super heated growth of computer networks.With TCP/IP becoming a de facto networking standard, a global addressing scheme, and a growing set of important applications, the infrastructure was in place for the creation of a truly international network. The Internet, in its modern form, had slowly begun to emerge.

One last step was needed, and it was taken by the National Science Foundation (NSF) in 1984. In that year, the NSF initiated a project whose goal was to bring the advantages of the Internet to the entire academic and professional community, regardless of discipline or relationship with the DOD. The NSF planned and built a national network called NSFNet, which used TCP/IP technology identical to the ARPANET. This new network interconnected six NSF supercomputer centers with dozens of new regional networks set up by the NSF. These new regional networks included thousands of users at places like universities, government agencies, libraries, museums, medical centers, and even high schools. Thus, by the mid-1980s, this emerging “network of networks” had grown to include many new sites and, even more important, a huge group of first-time users, such as students, faculty, librarians, museum staff, politicians, civil servants, and urban planners, toname just a few.

At about the same time, other countries began developing wide area TCP/IP backbone networks like NSFNet to interconnect their own medical centers, schools, research centers, and government agencies. As these national networks were created, they were also linked into this expanding network, and the user population continued to expand. For the first time since the development of networking, the technology had begun to have an impact on the wider community. A diagram of the state of internetworking in the late 1980s is shown in Figure 7.22.

People began referring to this entire collection of interconnected networks as “the Internet,” though this name was not officially accepted by the U.S. government until October 24, 1995.By early 2011, the Internet had grown to over 800 million computers located in just about every country in the world. The extraordinary growthof the Internet continues to this very day.In April 2025, it's estimated that around 5.56 billion people are using the internet worldwide. This represents a significant portion of the global population, with around two-thirds currently connected to the internet.