Advanced Research Projects Agency Network (ARPANET)

Definition - What does Advanced Research Projects Agency Network (ARPANET) mean?

The Advanced Research Projects Agency Network (ARPANET) is a predecessor to the modern Internet that was conceptualized in the 1950s, when computer scientists needed something better than the unreliable switching nodes and network links that were available at the time.

There were also only a limited number of large, powerful research computers and the researchers that had access to them were separated geographically. The Advanced Research Projects Agency (ARPA) commissioned the development of an advanced, reliable way to connect these computers through a newly devised packet switching network, which was called ARPANET.

Techopedia explains Advanced Research Projects Agency Network (ARPANET)

The ARPANET was a project funded by the U.S. government during the Cold War in order to build a robust and reliable communications network. This was done by connecting various computers that could communicate with each other simultaneously in a network that would not go down when a single node was taken out.

The initial groundwork for a computer network was laid by Joseph C. R. Licklider of Bolt Beranek and Newman (BBN). Licklider became the head of the behavioral sciences and command and control programs at ARPA in October 1963. He then convinced Ivan Sutherland and Bob Taylor to work on this concept. Bob Taylor had three computer terminals in his office connected to the three ARPA-sponsored computers:

  • The System Development Corporation (SDC) Q-32 at Santa Monica
  • Project Genie at the University of California, Berkeley
  • Multics at the Massachusetts Institute of Technology

When Taylor needed to talk to someone at another computer, he had to transfer to a different terminal for each connection. This was very frustrating for him and it lead to the concept of one terminal/computer being connected to a number of other terminals. This idea paved the way for the ARPANET and, eventually, the modern Internet.

It was Paul Baran of Rand Corporation who concluded that the strongest kind of network would be a packet switched network that would use any available communication line regardless of whether other lines were down. The ARPANET originally connected four computers:

  • A Honeywell DDP 516 computer at University of California, Los Angeles
  • An SDS-940 computer at the Stanford Research Institute
  • An IBM 360/75 at University of California, Santa Barbara
  • A DEC PDP-10 at the University of Utah

As more computers were connected to the network, compatibility problems arose. These problems were solved through the development of Transfer Control Protocol/Internet Protocol (TCP/IP) in 1982.

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