By the early 1970s, the practice of connecting once stand-alone computers together into general-purpose computer networks was barely five years old. But already there were more than half a dozen such networks: ARPANet, NPL Mark I, CYCLADES, and so on. ARPA itself was in the process of commissioning two more; the Packet Radio Network (PRNET), and the Satellite Network (SATNET).
But there was a big problem: none of these networks could talk to each other!
The solution came to several researchers in that early community around the same time. What was needed was a network of networks, a process known as "internetworking" or "internetting." By 1973, the European Informatics Network was experimentally connecting NPL in the UK and CYCLADES in France. Behind closed doors, Xerox's PARC research center was hooking up Ethernet to other local area networks that same year with its new PUP internetting protocol.
Bob Kahn at ARPA, who was funding the creation of PRNET and SATNET, had a very practical need -- to connect these military networks to each other and to the existing ARPAnet. He met up with another ARPANET alum, Vint Cerf, and in one inspired session in May of 1974 they created the first specification for ARPA's own internetting protocol -- TCP, or Transport Control Protocol.
It would be three years before they fully tested it, in a dramatic three-network international trial based from a research van in motion. It would be nearly 20 years of struggle before ARPA's protocol beat out all its rivals -- including heavyweight contenders from international standards organizations and computing giants like IBM and DEC.
By the early '90s Cerf and Kahn's protocol would emerge as the undisputed standard for internetting, or connecting computer networks to each other: the one we call "the" Internet. The Web won a separate battle to become the dominant online system for navigating information across the Internet. Together, the Web running over the Internet beat out earlier alternatives from Minitel to CompuServe, and our familiar online world took off.
On May 10tth, we celebrate 40 years since here, in the hotel Cabana in Palo Alto, Vint Cerf and Bob Kahn hammered out the rudiments of the standard that underlies today's online world, and connects over 3 billion people.