How a bread truck invented the internet
With thanks to Vint Cerf’s hearing aids
The TCP two-step
On August 27, 1976, the ‘bread truck’ – as it was often called — first used TCP to bridge the gap between the Arpanet and this packet radio setup. Sitting outside a former stage coach stop somewhere between San Francisco and Monterey, California, it fired an email across the two networks, shuttling packets through a makeshift gateway developed by BBN.
“For the first time, at least in a ceremonial sense, dissimilar networks were bridged by TCP,” wrote SRI’s Don Nielson in a 2002 paper celebrating the event.
And for all you Reg readers who think the high-tech revolution was driven by men and men alone: that BBN gateway was built by a woman. “What I remember is Vint Cerf hanging over my shoulder at two in the morning,” said Ginny Strazisar. “He kept saying ‘When are we going to get this? When are we going to get this?’”
Then DARPA added a third network to the mix: a packet satellite extravaganza that spanned the US, the United Kingdom, Norway, Germany, and Italy. The Arpanet already extended to the UK and to Norway, but for political reasons, DAPRA had trouble extending lines to the rest of Europe.
‘Ethernet in the sky’
“We ran into a problem with the TCP rules, which required all the carriers that were involved in running the links to all agree to any further extensions,” explained Bob Kahn. “That's what motivated us to do packet satellite — sort of like an Ethernet in the sky.”
So, in the fall of 1977, the bread truck went back to work, sending those packets across all three DARPA-funded networks — and a few more Strazisar-built gateways. “At this point, we’d demonstrated what all three networks could do, but we'd never gotten all three of the them running at the same time,” Cerf said. “TCP was supposed to show how multiple networks could be interconnected, and I thought it would be more convincing if we could do three networks rather than just two.”
Once those packets left SRI’s radio network, they made their way to Kjeller, Norway and on to London via the Arpanet. Then they were beamed skyward from an earth station in Goonhilly Downs, England, before coming down in the little town of Etam, West Virginia, halfway up the US east coast. And from there, they hoped back onto the Arpanet and made their way to USC.
They travelled a total of 88,000 miles. And the ping time was about two seconds.
When asked what the packets contained, Cerf, Kahn, et al didn't seem to remember. But they guessed that the truck simply logged into a University of Southern California mainframe. Yes, that’s a roundabout way to log into a mainframe. But it wasn’t about the end. It was about the means.
Proof of concept
Nothing ever became of this three-network hook-up. It was merely an experiment. A proof of concept. Well, nothing ever became of it unless you count the internet, which operates on so many of the same principles — and still uses TCP.
But why choose the three network transmission as the first internet connection? And not the two network hook-up that happened a year earlier? We have no idea. As Vint Cerf told us, “Bridging two networks is one thing. But things get much more difficult when you add a third.” But then he said things get even hairier when you add a fourth.
“Internet history is controversial. Everyone wants to be called the first,” said John Toole, executive and CEO of the Computer History Museum. “But whatever the case, no one can deny that there was an ugly-looking van in 1977 and some people inside it gave the world excitement, passion and new technology.” Make of that what you will. ®