ARPANET
First packet-switched network; technical foundation of the Internet.
The ARPANET, created by the U.S. Department of Defense’s Advanced Research Projects Agency (now DARPA), was the first wide-area network to use packet switching with distributed control. It also became one of the earliest networks to run the TCP/IP protocol suite. These two innovations later formed the technical basis for the Internet.
The project grew out of ideas from J. C. R. Licklider. Bob Taylor started the ARPANET in 1966, aiming to let remote computers share resources. Taylor put Larry Roberts in charge as program manager. Roberts made key choices about the request for proposals to build the network. He adopted Donald Davies’ concepts and designs for packet switching and also asked Paul Baran for input. In 1969, ARPA gave the contract to build the network’s Interface Message Processors (IMPs) to Bolt Beranek & Newman (BBN). Bob Kahn led the design and created the first network protocol. Roberts brought in Leonard Kleinrock at UCLA to develop mathematical methods for analyzing the packet network.
The first computers were linked in 1969. The Network Control Program, led by Steve Crocker at UCLA and other graduate students like Jon Postel, was implemented in 1970. The network was declared operational in 1971. Later software added remote login and file transfer, which enabled an early form of email. The network grew quickly, and in 1975 the Defense Communications Agency took over its operation.
Bob Kahn moved to DARPA and, with Vint Cerf at Stanford, worked on the Transmission Control Program for internetworking. This work led to a protocol that could join multiple separate networks into a network of networks. It drew on ideas from the French CYCLADES project, directed by Louis Pouzin, and from Bob Metcalfe at Xerox Parc. On January 1, 1983, version 4 of TCP/IP went into production use on the ARPANET, after the Department of Defense made it the standard for all military computer networking.
Access widened in 1981 when the National Science Foundation (NSF) funded the Computer Science Network (CSNET). In the early 1980s, the NSF also funded national supercomputing centers at several universities. In 1986, the NSFNET project provided network access and interconnectivity. The ARPANET was formally shut down in 1990, after partnerships with the telecom and computer industries had ensured private-sector growth and commercialization of an expanded worldwide ne
- field
- Computer networking
- known_for
- First wide-area packet-switched network; technical foundation of the Internet
- established
- 1966 (project initiated); 1969 (first computers connected); 1971 (declared operational)
- decommissioned
- 1990
- funder
- Advanced Research Projects Agency (ARPA), United States Department of Defense
Lore & Background
Building on the ideas of J. C. R. Licklider, Bob Taylor initiated the ARPANET project in 1966 to enable resource sharing between remote computers. Taylor appointed Larry Roberts as program manager. Roberts made key decisions about the request for proposal to build the network, incorporated Donald Davies' concepts and designs for packet switching, and sought input from Paul Baran. In 1969, ARPA awarded the contract to build the Interface Message Processors (IMPs) to Bolt Beranek & Newman (BBN). The design was led by Bob Kahn, who developed the first protocol for the network. Roberts engaged Leonard Kleinrock at UCLA to develop mathematical methods for analyzing the packet network technology.
Reader's Guide
The ARPANET's significance lies in its role as the first operational packet-switched network and the direct precursor to the modern Internet. By implementing distributed control and the TCP/IP protocol suite, it demonstrated that multiple separate networks could be joined into a network of networks. Its development spurred key innovations, including packet switching (based on the work of Donald Davies and Paul Baran), the Interface Message Processor concept, and early forms of email, remote login, and file transfer. The network expanded rapidly, and operational control passed to the Defense Communications Agency in 1975. After the Department of Defense made TCP/IP standard for all military computer networking in 1983, the ARPANET was formally decommissioned in 1990, following private sector expansion and commercialization of the Internet.
Did You Know?
- The ARPANET was the first wide-area packet-switched network with distributed control.
- Bob Taylor initiated the ARPANET project in 1966 after having three different computer terminals in his office, each with separate user commands.
- The contract to build the Interface Message Processors was awarded to Bolt Beranek & Newman (BBN) in 1969.
- Version 4 of TCP/IP was installed in the ARPANET for production use on 1 January 1983.
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