Tcp/ip Turns 40

Earlier this month, more than 150 people gathered in Mitchell Park in Palo Alto, CA, to mark the 40th anniversary of the Transport Control Protocol, or TCP.

TCP (later modified with the assigning of some functions to an Internet Protocol layer to TCP/IP) is the internetworking protocol that went on to become the standard that makes today’s Internet possible. Two men—Vinton Cerf and Bob Kahn—wrote the protocol in a hotel room in Palo Alto in 1973, building on the work of many other networking pioneers (the two were jointly honored with the ACM A.M. Turing Award in 2004 for designing and implementing the protocol).

Computer networks predated TCP/IP. By 1974, several already existed, prominent among them the U.S. Defense Advanced Research Projects Agency (DARPA) ARPAnet, the CYCLADES research network in France, and the Mark I and II at the U.K.’s National Physical Laboratories. Each of these networks used its own protocol: the computers could share information within the network, but not from one network to another.

Electrical engineer Bob Kahn was working with the Advanced Research Projects Agency (ARPA, the predecessor of DARPA) in 1973, developing a replacement for ARPAnet’s Network Control Program (NCP) protocol. That spring, Vinton Cerf, who had developed NCP and was working at Stanford’s Digital Systems Laboratory, joined Kahn, and the two men focused on open-architecture models.

By September 1973, Cerf and Kahn were ready to present their scheme at the NATO Advanced Study Institute on Computer Communications at the University of Sussex in England. In May 1974, the duo published their paper "A Protocol for Packet Network Intercommunication" in IEEE Transactions on Communications. In 1975, Stanford University and University College London performed a two-network demonstration; and in November 1977, a message was successfully sent between networks in the U.S., the UK, and Norway, marking the first true multi-network communication (the U.S. base for the test was a delivery truck belonging to the Stanford Research Institute, today known as SRI International.)

It would still take a while before TCP/IP became the standard internetworking protocol, but ARPAnet was running on it by 1983, and throughout the 1980s industry groups and major vendors continued to adopt and promote it. By the early 1990s, it was the undisputed standard.

"From such distant origins, the global Internet has emerged, fed by the ideas and efforts of countless contributors around the globe," said Cerf, now ACM’s president. "Today, some three billion users use the Internet via wired and wireless devices; new services are constantly being offered. We celebrate the 40th anniversary of the first publication of the Internet design and look with great curiosity towards the ever more connected Internet environment of the future."

The event in Mitchell Park was organized by Mei Lin Fung, founder of the Franchise for Humanity and active in many technology- and society-oriented projects. Fung organized Douglas Engelbart’s Program for the Future in 2008 and recalled, "Vint had been speaking with us since then about doing something for TCP/IP," she said. "So it’s been five years in the genesis, but really, it came down to a meeting in March of this year. I met Vint in person again, and he said May would be a good date. A group of us at the Innovation for Jobs Conference at SRI agreed to become the planning committee."

The climax of the celebration was the unveiling of a plaque commemorating the creation of TCP, to be installed in the lobby of the Crowne Plaza Cabaña Hotel/Crowne Plaza Palo Alto (called the Hyatt Cabaña in 1973), the hotel where Kahn and Cerf wrote the protocol spec.

"We had 165 people who registered and about that number who came," says Fung. Speakers during the event included Cerf; Judy Estrin, who worked with Cerf at Stanford; Yogen Dalal, one of Cerf’s students; John Schoch, who worked on Xerox PARC’s PUP protocol, a TCP/IP predecessor, and Palo Alto mayor Nancy Shepherd.

It was important to Cerf that the contributions of multiple people were recognized, said Fung. "People often don’t have time to tell a complex story like this, so they look for one or two people and say, ‘you’re the hero inventor.’ But there was no hero inventor; it was a whole lot of people who believed in something and worked over many, many years to make it work. Vint Cerf knew it was important to get that point out so that the community would be recognized."

Many of the attendees at the event had not seen each other for decades, Fung noted. "There was a lot of catching up and a lot of joy, and bringing them together let their families and grandchildren realize, ‘oh, that’s what you did!’"

Logan Kugler is a freelance technology writer based in Clearwater, FL. He has written for over 60 major publications.