When the development of TCP started, a name was required for its predecessor, and the pre-existing acronym 'NCP' (which originally referred to Network Control Program, the software that implemented this stack) was organically adopted for that use.
[3][4] Eventually, it was realized that the original expansion of that acronym was inappropriate for its new meaning, so a new quasi-backronym was created, 'Network Control Protocol' — again, organically, not via a formal decision.
Working with Jon Postel and others, they designed a host-to-host protocol, known as the Network Control Program, which was developed in the ARPANET's earliest RFC documents in 1969 after a series of meetings on the topic with engineers from UCLA, University of Utah, and SRI.
"[nb 2] After approval by Barry Wessler at ARPA,[11] who had ordered certain more exotic elements to be dropped,[12] it was finalized in RFC 33 in early 1970,[13] and deployed to all nodes on the ARPANET in December 1970.
Widespread deployment across the Arpanet began in earnest in 1981, and on several days toward the end of 1982 the backbone routers disabled NCP traffic for most hosts to test the network's readiness for the transition.
[22][23][24][25] Despite the "mandatory" flag-day transition, a number of sites continued use of NCP into mid-1983,[26] but these were special cases that required permission from the backbone operators, and all hosts were eventually switched to TCP/IP or removed.