In 1969, the United States DoD (Department of Defense) initiated a research project under the ARPA agency (Advanced Research Projects Agency) which would see if a robust computer network could be built. This project became the highly successful ARPANET which spawned the TCP/IP protocols and became the core of today's Internet.

TCP/IP is actually a set (or suite) of protocols. In 1973, the DoD threw away the original protocols used in the ARPANET because they weren't scaling well. That is, these protocols no longer functioned efficiently as the number of computers on the ARPANET mushroomed from 4 in 1969 to around 60. So Vint Cerf and Robert Kahn headed the team that wrote their replacements, and these protocols, the so-called TCP/IP suite, are still in constant use today and probably will remain important for at least another decade. They have scaled admirably because today there are millions of hosts worldwide.