They developed TCP/IP (Transmission Control Protocol/Internet Protocol). TCP handles data assembly/disassembly, while IP ensures packets reach the correct address.

On October 29, 1969, the first message was sent between UCLA and the Stanford Research Institute (SRI) . The intended message was "LOGIN," but the system crashed after the first two letters, making "LO" the first data ever transmitted over the network.

ARPANET, the first real prototype of the internet, was launched by ARPA to allow researchers at different universities to share computer resources.