The DoD funded research sites throughout the United States, and in 1968, the Advanced Research Projects Agency (ARPA) contracted with Bolt, Beranek, and Newman, Inc. (BBN), a private company, to build a network based on the packet switching technology that had been developed for better transmission of computer data.

The 1970s: The Growth Spurt Begins
When the Advanced Research Projects Agency Network (ARPANET) project began, no one anticipated that the network would grow to the extent that it did. Throughout the 1970s, more nodes or access points were added, both domestically and abroad.

The 1980s: More Is Better 
In 1983 the ARPANET was split, and Military Network (MILNET), which was integrated with the Defense Data Network (DDN), took 68 of the 113 existing nodes. The DDN had been created the previous year. The Domain Name System (DNS) was introduced in 1984, providing a way to map "friendly" host names to IP addresses. It was much more efficient and convenient than previous methods. These methods are discussed in Chapter 8, "Networking Fundamentals". In 1984, there were more than 1,000 host computers on the network.

During the last half of the 1980s, networking increased considerably. For instance, the National Science Foundation (NSF) created supercomputer centers in the United States at Princeton, the University of California, the University of Illinois, and Cornell University. The Internet Engineering Task Force (IETF) was also created during this time. By 1987, there were 10,000 hosts on the network, and by 1989, that number increased to over 100,000.

The 1990s: The Net Becomes Big Business
The phenomenal growth rate of the 1980s was nothing compared to what came in the 1990s. ARPANET evolved into the Internet, with the U.S. government getting involved in pushing the development of the so-called information superhighway. The National Science Foundation Network (NSFNET) backbone was upgraded to T3 speed (that is, 44.736 Mbps), and in 1991, it sent more than 1 trillion bytes per month. The Internet Society (ISOC) was formed, and in 1992 more than 1 million hosts existed on the Internet.

The 1990s saw the explosion of commerce on the Internet. As more and more college students, faculty, individual home users, and companies of all sizes got connected, the business world recognized the opportunity to reach a large and expanding affluent market. By 1995, online advertising had caught on, online banking had arrived, and even a pizza could be ordered over the Internet.

The last half of the last decade of the century ushered in new major developments on an almost daily basis. Streaming audio and video, "push" technologies, and Java and ActiveX scripting took advantage of higher performance connectivity that was available at lower and lower prices. Domain names became big business, with particularly desirable names selling for upwards of one million U.S. dollars. Today, there are millions of sites that exist on the World Wide Web, with millions of host computers participating in this great linking. Figure shows a timeline of significant events in PC networking history. Figure shows a graph illustrating the growth of the Internet.