Definition - What does Network Control Protocol (NCP) mean?
Network Control Protocol (NCP) was an early protocol implemented by ARPANET, the world's first operational packet-switching network that later evolved into what became the Internet. NCP allowed users to access and use computers and devices at remote locations and to transmit files between computers. NCP provided the middle layer of the protocol stack, and enabled application services such as email and file transfer.
Whether the term is Network Control Protocol or Network Control Program is a matter of some debate, as both terms are used to refer to this ARPANET protocol.
NCP was replaced by TCP/IP in the 1980s.
Techopedia explains Network Control Protocol (NCP)
NCP connected processes running on different ARPANET computers. Protocols on the ARPANET in the physical layer, data link layer and network layer were implemented on separate interface massage processors. This meant that NCP acted much like a transport layer, as it defined the procedure for connecting two hosts.
The switch to TCP/IP in 1983 marked a major move toward the modern Internet. TCP/IP remains the standard protocol of online communication.