23 Facts About ARPANET


The ARPANET was established by the Advanced Research Projects Agency of the United States Department of Defense.

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ARPANET incorporated Donald Davies' concepts and designs for packet switching, and sought input from Paul Baran.

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Access to the ARPANET was expanded in 1981, when the National Science Foundation funded the Computer Science Network (CSNET).

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The ARPANET was formally decommissioned in 1990, after partnerships with the telecommunication and computer industry had assured private sector expansion and future commercialization of an expanded world-wide network, known as the Internet.

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ARPANET developed the theoretical model of distributed adaptive message block switching.

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ARPANET convinced Ivan Sutherland and Bob Taylor that this network concept was very important and merited development, although Licklider left ARPA before any contracts were assigned for development.

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ARPANET gave the first public presentation, having coined the term packet switching, in August 1968 and incorporated it into the NPL network in England.

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The NPL network and ARPANET were the first two networks in the world to use packet switching, and were themselves interconnected in 1973.

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ARPANET was not started to create a Command and Control System that would survive a nuclear attack, as many now claim.

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Rather, the ARPANET came out of our frustration that there were only a limited number of large, powerful research computers in the country, and that many research investigators, who should have access to them, were geographically separated from them.

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ARPANET incorporated distributed computation, and frequent re-computation, of routing tables.

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The ARPANET was designed to survive subordinate-network losses, since the principal reason was that the switching nodes and network links were unreliable, even without any nuclear attacks.

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The first permanent ARPANET link was established on 21 November 1969, between the IMP at UCLA and the IMP at the Stanford Research Institute.

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Thereafter, the ARPANET grew: 9 IMPs by June 1970 and 13 IMPs by December 1970, then 18 by September 1971; 29 IMPs by August 1972, and 40 by September 1973.

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ARPANET was a research project that was communications-oriented, rather than user-oriented in design.

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Access to the ARPANET was expanded in 1981, when the National Science Foundation funded the Computer Science Network (CSNET).

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In September 1984 work was completed on restructuring the ARPANET giving U S military sites their own Military Network for unclassified defense department communications.

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The original IMPs and TIPs were phased out as the ARPANET was shut down after the introduction of the NSFNet, but some IMPs remained in service as late as July 1990.

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Inter-networking protocols developed by ARPA and implemented on the ARPANET paved the way for future commercialization of a new world-wide network, known as the Internet.

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Unlike modern Internet datagrams, the ARPANET was designed to reliably transmit 1822 messages, and to inform the host computer when it loses a message; the contemporary IP is unreliable, whereas the TCP is reliable.

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The NCP interface allowed application software to connect across the ARPANET by implementing higher-level communication protocols, an early example of the protocol layering concept later incorporated in the OSI model.

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But, because of technical shortcomings, conference calls over the ARPANET never worked well; the contemporary Voice over Internet Protocol was decades away.

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Purdy Polynomial hash algorithm was developed for the ARPANET to protect passwords in 1971 at the request of Larry Roberts, head of ARPA at that time.

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