ARPANET – Advanced Research Projects Agency NETwork
Advanced Research Projects Agency Network was the beginning of what we consider the Internet today. The development began in 1966 by the United States Defense Advanced Research Projects Agency (ARPA) with the motto of connecting multiple computers at different geographical locations.
ARPANET was a large wide-area network established in 1969, linking many universities and research centers. It served as a testbed for early networking research and development of Internet. The network was based on packet switching which was a new concept at that time.
ARPA, a US defence research agency, formed in 1957 to develop military science and technology. Its name was changed to Defense Advanced Research Projects Agency (DARPA) in 1971. So, ARPANET is sometimes referred to as DARPANET. DARPA was changed back to ARPA in 1993 and back to DARPA again in 1996.