The Defense Communications Agency Establishes TCP/IP as the Basis for ARPANET

In 1982 DCA (Defense Communications Agency) and ARPA established the Transmission Control Protocol (TCP) and IP (Internet Protocol), as the protocol suite, commonly known as TCP/IP, for ARPANET. This led to one of the first definitions of an “internet” as a connected set of networks, specifically those using TCP/IP, and the “Internet” as connected TCP/IP internets.