In a current feature on Unsung Tech Innovators Computerworld interviews Robert Kahn who, along with Vint Cerf came up with the TCP/IP protocol upon which the Internet is based. Kahn notes that the 30th anniversary of their first successful “internetworking” demo just passed.

From the article:

Initially, in 1973, DARPA contracted with Cerf to work with Kahn on aspects of the nascent Internet project, “after I had the basic idea down,” to help complete the design and implementation of the TCP (Transmission Control Protocol), Kahn says. The idea was to replace the Arpanet’s by-then-outdated method of passing along messages, called the Network Control Protocol.

The Kahn and Arpanet story goes back to October 1966, when Kahn was taking a break from his professorship at MIT and working at Bolt Beranek and Newman (BBN). Back then, BBN was primarily an architectural acoustics research firm in Cambridge, Mass.

“BBN ended up getting the contract to build the Arpanet, and a four-node version got deployed and [was] working in December 1969,” Kahn explains. Those first nodes linked computers at UCLA, the Stanford Research Institute, the University of California at Santa Barbara and the University of Utah. But it took almost three more years for the research community to get those host computers connected to the Net. The first public demonstration of the Arpanet was in 1972, when approximately 50 nodes were operating, he says.

Kahn finds it funny that, looking back, people think getting the funding for a program to do the Internet and making it happen was “a slam-dunk.”

“I’ll tell you, the only reason we succeeded in building it was that no one cared enough in the early 1970s to get involved and try to stop it,” he says. “So few companies had time-sharing computers back then, and thus, there wasn’t seen to be much of a market for interactive computer networks. And so there was no effort in the private sector to interconnect nonexistent networks to each other.”

DARPA happened to have three such networks in existence or in development, Kahn says, “so we could imagine the problem and attempt to solve the interconnection problem. It was not until later that alternate networks, such as the Ethernet and personal computers, emerged in the commercial marketplace. That made a big difference.”

One big moment that isn’t often recognized, he says, is when DARPA — working with a number of contractors, including Collins Radio, BBN and others — demonstrated the first successful TCP connection traversing three dissimilar but interconnected networks. November 22, 2007, marked the 30th anniversary of that demo.

It was an event that Kahn believes should be more recognized because, like today’s Internet, it was the “internetworking” of three disparate networks, and it foreshadowed the cellular and Wi-Fi systems of today.