On January 1, 1983, ARPANET system architects initiated the cutover from the existing Network Control Program (NCP) with the Transmission Control Protocol/Internet Protocol (TCP/IP) on all hosts. The transition would be complete by June 1983. By 1984, over 100 universities and research facilities in the United States and Europe were connected using what is now regarded as the universal standard for global networking. TCP/IP became the foundation of the Internet as we know it.
Before this momentous decision, networks would use a mix of incompatible protocols and proprietary vendor stacks. NCP, which was displaced by TCP/IP, was designed to be ARPANET-only, and had no internetworking capabilities. With TCP/IP, an internetworking (and thus ‘Internet’) protocol was born, connecting these networks with those beyond their initial confines.
