Network Control Program (NCP)

The software for establishing links between network sites in the ARPANET was the Network Control Program (NCP), completed in c. 1970. Further development in the early 1970s by Robert E. Kahn and Vint Cerf let to the formulation of the Transmission Control Program, and its specification in December 1974 in RFC 675. This work also coined the terms catenet (concatenated network) and internet as a contraction of inter-networking, which describe the interconnection of multiple networks. This software was monolithic in design using two simplex communication channels for each user session.