How a bread truck invented the internet
With thanks to Vint Cerf’s hearing aids
On November 22, 1977, as it motored down the street somewhere south of San Francisco, a souped-up delivery van sent some information to a computer lab at the University of Southern California, 400 miles away. No one can quite remember what the information was, but that really doesn't matter. What matters is the way it travelled.
It didn’t travel as the crow flies. It traveled from San Francisco to Boston, before a trip to Norway and Britain. And from Britain, it bounced back to Southern California by way of a tiny town in West Virginia.
And it didn’t travel over one data network. Thanks to a certain protocol called TCP, it traveled over three: a wireless packet radio network covering a few California hilltops, a satellite hookup bridging the Atlantic, and the Arpanet, a wired network that would go on to much bigger things.
For some, this dipsy-doodle data transmission marks the world’s first internet connection. But you can disagree if you like.
The thirtieth anniversary of this little-known event was celebrated last week at the Computer History Museum in Mountain View, California, not far from where the souped-up delivery van did its transmitting. TCP founding fathers Vint Cert and Bob Kahn were on hand, along with 16 others who helped send those packets across the world and back again.
“The point is that we did this over three separate networks,” Cerf told us. “It was true inter-networking.”
‘The bread truck’
The delivery van — which looks an awful lot like an old-school bread truck — belonged to SRI International, the research center most famous for cooking up hypertext and the computer mouse. Since about 1975, the van had operated as a “mobile node” on a packet radio network that stretched across Silicon Valley and up to San Francisco.
SRI had built this wireless network with more than a little help from the University of California Los Angeles (UCLA) and a trio of private contractors: Bolt Beranek and Newman of Boston, Collins Radio of Dallas, Texas, and Network Analysis near New York City. But it was funded by DARPA (Defense Advanced Research Projects Agency), the defense department operation where Cerf and Kahn spent time developing the Transmission Control Protocol. You know, TCP – the protocol that now drives the internet.
DARPA, of course, had already bootstrapped the Arpanet, a packet switched network spanning various government agencies and academic institutions. The Arpanet, as you all know, eventually morphed into the worldwide extravaganza we use today.
But as a defense department operation, DARPA also saw the need for wireless transmission. “When you’re in a militarized environment and you’re mobile, you can’t have wires,” Cerf said. “Tanks with wires don’t work very well.”
According to a Computer History Museum hype-machine, this 100 to 400 Kbps packet radio network “foreshadowed WiFi.” And that sounds about right. It was only slightly more difficult to deal with.
“I was the only guy who could sit in a room where a demo was going on and tell that the packet radio network was actually working,” said Cerf. “I have hearing aids, and they would pick up the signal. It sounded like crinkling paper. So when the crinkling paper noise stopped, I would kick the technician under the table and he would re-power the equipment.”
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. ®