The Network Control Program (sometimes the abbreviation NCP is mistakenly expanded to Network Control Protocol, but this term is not found in the contemporary documentation) was the original protocol suite of the ARPANET.

In NCP, the physical layer, the data link layer, and the network layer were all specified by the Host/IMP Protocol . The transport layer was the Host-to-Host Protocol , together with the Initial Connection Protocol . Layers above that were all joined in with the application (e.g. FTP, SMTP, etc).

On January 1, 1983, parts of NCP were rendered obsolete when the ARPANET changed its core networking protocols from NCP to the more flexible and powerful TCP/IP protocol suite, marking the start of the Internet as we know it today.

Further reading

• Feinler, E.; Postel, Jon B. ARPANET Protocol Handbook (Network Information Center, Menlo Park, 1978)