Advanced Research Projects Agency network, the first computer network to use packet switching. Funded by the U.S. Advanced Research Projects Agency in 1969, ARPANET linked research computers on two University of California campuses with the Stanford Research Institute and the University of Utah. In 1983, with more than 300 computers connected, its protocols were changed to TCP/IP, and it became known as the Internet. In 1987, when the National Science Foundation (NSF) began to develop a high-speed fiber-optic backbone to connect supercomputer centers, intermediate networks of regional ARPANET sites began connecting to the backbone. In 1995, commercial Internet service providers assumed control of the major backbones in the United States. Traffic over the "Net" continues to expand.