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Louis Pouzin Coins the Concept and Term "Datagram"


In November 1973 the first demonstration, using three hosts and one packet switch, occurred on CYCLADES, a French packet switching network designed and directed by Louis Pouzin. CYCLADES was developed to explore alternatives to the ARPANET design and to support network research generally. It was sponsored and coordinated by the French government, through the Institut de Recherche en lnformatique et en Automatique (IRIA), the national research laboratory for computer science in France (now known as INRIA). Several French computer manufacturers, research institutes and universities contributed to the effort. 

CYCLADES was the first network to make the hosts responsible for the reliable delivery of data, rather than the network itself, using unreliable datagrams and associated end-to-end protocol mechanisms. Within the CYCLADES project Pouzin coined the concept and term datagram, by combining the words data and telegram. 

In 1974 Vinton Cerf and Robert Kahn adopted these concepts for the creation of TCP. They were later adopted for the creation of the Internet Protocol (IP).

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