number of packet-switched networks were built or contemplated, including the ARPAnet (the terrestrial packet-switched network hooking together computers at different ARPA-funded universities and research labs), an international satellite network (SATnet), and a mobile spread-spectrum packet radio network (PRnet). Faced with the challenge of hooking these disparate networks together, Vinton Cerf and Robert Kahn (1974) proposed the core idea of the Internet.
