ARPANETs

ARPANETs were the early packet-switched networks funded by the U.S. Department of Defense's Advanced Research Projects Agency (ARPA). Initiated in the late 1960s, the effort sought to connect geographically dispersed research centers to share computing resources and to preserve communications during a crisis. The first operational ARPANET link, established in 1969, connected UCLA to the Stanford Research Institute, with UC Santa Barbara and the University of Utah added soon after. The 1969 test included the historic attempt to transmit the word 'LOGIN' across the network, which was interrupted after the first two letters.

Technically, ARPANET relied on Interface Message Processors (IMPs) made by Bolt, Beranek and Newman (BBN) and used the Network Control Program (NCP) protocol at first. It adopted TCP/IP in 1983, enabling disparate networks to connect as a single global network of networks. The ARPANET expanded to universities and research institutions worldwide, becoming a central backbone for early email, remote login (telnet), and file transfer (FTP).

With the growth of the Internet in the 1980s, ARPANET's role gradually shifted as NSFNET and other networks increasingly interconnected. ARPANET was formally decommissioned in 1990, though its legacy persisted in the now ubiquitous TCP/IP protocols and the global Internet. The ARPANET project is widely regarded as a foundational milestone in networking and digital communication, illustrating how government-funded research can catalyze a broader technological revolution.