Research into packet switching started in the early 1960s and packet switched networks such as Mark I at NPL in the UK,[8]ARPANET,CYCLADES,[9][10]Merit Network,[11]Tymnet, and Telenet, were developed in the late 1960s and early 1970s using a variety of protocols. The ARPANET in particular led to the development of protocols for internetworking, where multiple separate networks could be joined together into a network of networks.[citation needed]
The first two nodes of what would become the ARPANET were interconnected betweenLeonard Kleinrock's Network Measurement Center at the UCLA's School of Engineering and Applied Science and Douglas Engelbart'sNLS system at SRI International (SRI) inMenlo Park, California, on 29 October 1969.[12] The third site on the ARPANET was the Culler-Fried Interactive Mathematics center at the University of California at Santa Barbara, and the fourth was the University of Utah Graphics Department. In an early sign of future growth, there were already fifteen sites connected to the young ARPANET by the end of 1971.[13][14] These early years were documented in the 1972 film Computer Networks: The Heralds of Resource Sharing.
Early international collaborations on ARPANET were sparse. For various political reasons, European developers were concerned with developing the X.25networks.[15] Notable exceptions were theNorwegian Seismic Array (NORSAR) in June 1973,[16] followed in 1973 by Sweden with satellite links to the Tanum Earth Station andPeter T. Kirstein's research group in the UK, initially at the Institute of Computer Science,University of London and later at University College London.[citation needed]
In December 1974, RFC 675 – Specification of Internet Transmission Control Program, by Vinton Cerf, Yogen Dalal, and Carl Sunshine, used the term internet as a shorthand forinternetworking and later RFCs repeat this use.[17] Access to the ARPANET was expanded in 1981 when the National Science Foundation (NSF) developed the Computer Science Network (CSNET). In 1982, theInternet Protocol Suite (TCP/IP) was standardized and the concept of a world-wide network of fully interconnected TCP/IP networks called the Internet was introduced.
TCP/IP network access expanded again in 1986 when the National Science Foundation Network (NSFNET) provided access tosupercomputer sites in the United States from research and education organizations, first at 56 kbit/s and later at 1.5 Mbit/s and 45 Mbit/s.[18] Commercial Internet service providers (ISPs) began to emerge in the late 1980s and early 1990s. The ARPANET was decommissioned in 1990. The Internet was commercialized in 1995 when NSFNET was decommissioned, removing the last restrictions on the use of the Internet to carry commercial traffic.[19] The Internet started a rapid expansion to Europe and Australia in the mid to late 1980s[20][21] and to Asia in the late 1980s and early 1990s.[22]
Since the mid-1990s the Internet has had a tremendous impact on culture and commerce, including the rise of near instant communication by email, instant messaging,Voice over Internet Protocol (VoIP) "phone calls", two-way interactive video calls, and the World Wide Web[23] with its discussion forums, blogs, social networking, and online shopping sites. Increasing amounts of data are transmitted at higher and higher speeds over fiber optic networks operating at 1-Gbit/s, 10-Gbit/s, or more.
The Internet continues to grow, driven by ever greater amounts of online information and knowledge, commerce, entertainment andsocial networking.[26] During the late 1990s, it was estimated that traffic on the public Internet grew by 100 percent per year, while the mean annual growth in the number of Internet users was thought to be between 20% and 50%.[27] This growth is often attributed to the lack of central administration, which allows organic growth of the network, as well as the non-proprietary open nature of the Internet protocols, which encourages vendor interoperability and prevents any one company from exerting too much control over the network.[28] As of 31 March 2011, the estimated total number ofInternet users was 2.095 billion (30.2% of world population).[29] It is estimated that in 1993 the Internet carried only 1% of the information flowing through two-way telecommunication, by 2000 this figure had grown to 51%, and by 2007 more than 97% of all telecommunicated information was carried over the Internet.[30]
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