The Internet is 35 years old. J.C.R. Licklider of the Massachusetts of Technology first proposed a global network of computers in 1962, and moved to the Defense Advanced Research Projects Agency (DARPA) to develop it. Leonard Kleinrock developed the theory of packet switching, the basis of Internet connections. On September 2, 1969, Stephen Crocker and Vinton Cerf, two graduate students at the University of California Los Angeles (UCLA), linked two large computers using a 15-foot cable and tested a new way to exchange data. In January, three other "nodes" were added to this network. The earliest idea of a computer network intended to allow general communication between users of various computers was the ARPANET, the world's first packet switching network.