The Internet developed from the initial efforts of the US Department of defence to construct a computer network that would still allow communication if individual segments were to fail by providing alternative routes across the network. This network, the ARPAnet, came into use in 1968. Another feature of ARPAnet was that the individual computers were responsible for correctly addressing and checking connections.
To send data across ARPAnet required only that the sending computer wrapped the message in a standard envelope - the Internet Protocol (IP) packet - with the correct address for the destination computer. This is the origin of the IP address still used today. The Transmission Control Protocol (TCP) was devised to prevent packets from overlapping on the same part of the network.
The first European connections to ARPAnet were the UK and Norway in 1973. The UK academic community were not connected until the founding of JANET.
The late 1980s saw the creation by the US National Science Foundation (NSF) of five regional supercomputing centres; the NSFnet was built in 1986 to link them together by special telephone lines. Regional networks were allowed to attach to this 'backbone'.
In recent years control of the NSFnet has been given over to a consortium of commercial companies such as AT&T and MCI. Thereby, linking the commercial networks to the academic networks worldwide.