Birth of the Internet

The birth of the Internet resulted from a research effort funded by the American ARPA (Advanced Research Projects Agency), in a Cold War context where the resilience of communications was becoming a strategic concern. As early as 1961, Leonard Kleinrock at MIT formalised packet-switching theory, alongside the independent work of Paul Baran (RAND, 1964) and Donald Davies (NPL, 1965). On 29 October 1969, the first IMP-to-IMP message of ARPANET travelled between UCLA and SRI, linking four nodes and then some twenty by 1971. Ray Tomlinson invented email the same year and chose the "@" sign as a separator. In 1974, Vinton Cerf and Robert Kahn published the TCP specification, an inter-network protocol which, after its split into TCP/IP in 1978, made it possible to connect heterogeneous networks. Robert Metcalfe and David Boggs developed Ethernet at Xerox PARC in 1973, standardising the local area network. The historic switchover of ARPANET to TCP/IP took place on 1 January 1983, a date sometimes called the "birth of the Internet". Paul Mockapetris proposed DNS in 1983, freeing users from memorising IP addresses. In 1986 the NSF deployed NSFNET, the academic backbone; from 1989 the first commercial ISPs (UUNET, PSINet) opened the way to privatisation, sealed in 1995 with the decommissioning of NSFNET. Linus Torvalds released the Linux kernel in 1991, a free operating system that would become the dominant infrastructure of Internet servers, while Tim Berners-Lee brought the first Web server online at CERN the same year. This period transformed a military research project into a worldwide civilian infrastructure: from 4 nodes in 1969, the Internet reached 10 million hosts in 1995 and some 16 million users. The founding principles — network of networks, open protocols, decentralisation, end-to-end, best-effort — constitute a lasting technical and political heritage. As the ARPANET/NSFNET era drew to a close, the hypertext web imagined by Berners-Lee opened directly onto the following period, that of the consumer Web.