Journey of An E-Mail Message Submitted by Veronica Pasquale

When I read John Dyson's "Journey of An E-Mail" in the March 2000 Reader's Digest recently, I was fascinated by Mr. Dyson's story of "What really happens when you click Send" and thought you might be, too. Mr. Dyson sent a picture of "Mr. D", his family pet, from London, England, to Doug and Julie Young at a farmhouse in Ohio. He clicked "Send", and its first stop was west London, where Cable & Wireless Co. connects his computer to the Internet by telephone lines. A modem there checked his name and password and asked what he wanted, whereupon Mr. Dyson's computer answered, "I've got mail".

Cable & Wireless then located "BuckeyeNet" (the company connecting the Youngs to the Internet) by consulting one of 13 core directories (ten in the U.S., two in Europe, and one in Japan) that hold every Internet address in the entire world.

Would you believe the picture of "Mr. D" was then electronically chopped into tiny pieces and put into separate envelopes totaling about 120 packets!? This, I understand, is done to every piece of e-mail! Each piece was stamped with BuckeyeNet's address along with Mr. Dyson's address, so the jigsaw puzzle could be reassembled. But these pieces did not go all at the same time. Instead, one "scout" piece was sent first to make a connection with BuckeyeNet. Next stop: a gateway router to help find the way.

Mr. Dyson reports that his Cable & Wireless router sent "scout" across London to the company's transmission center in Docklands, where another router fed it into the stream of e-mail packets heading for the base station of the transatlantic Gemini Cable at Cornwall. Time? Four milliseconds - one lightening flash. There, Mr. D's scout piece "jostled for elbowroom with a torrent of transatlantic electronic traffic . . . along a fiber-optic cable known in the trade as pipe." A laser flashing 10 billion times a second fires digital on/off signals, and the scout piece is fired off at about 120,000 miles a second - more than half the speed of light. Awesome!

40 milliseconds later (1/10 of a blink of an eye), Mr. D's scout packet came ashore at Manasquan, N.J., zipped along poles and flashed into downtown Manhattan. Next, the scout packet was diced into even tinier pieces, switched into high-capacity "fat pipes" crossing the continent, then went on a "really wild ride, zipping through pipe beside railroad tracks, into and out of Philadelphia, up the Ohio Valley, through Cleveland and into another telephone exchange near Chicago, where the scout pieces were restored. It all took a fraction of a second."

The scout packet next raced through Chicago and Detroit before landing in Columbus, Ohio, where a router switched Mr. D into a skinny pipe to BuckeyeNet, five miles from the Youngs. BuckeyeNet's mail server unwrapped Mr. D's scout packet and in 1/10 of a second, sent an acknowledgment to London, whereupon five packets "hit the road" from London. When this bunch arrived, Ohio said: "I got the first five, give me five more." The last bit of Mr. D straggled into BuckeyeNet's server less than half a minute after Mr. Dyson had originally clicked Send.

It was interesting to note that while all this was happening, Mr. Young was pouring pellets of dog food into a dish for his dog. This is "a perfect metaphor for understanding why e-mails are diced into packets and cells. Like pellets, they pour more easily and therefore travel much faster." Makes sense to me.

When Mr. Young clicked Get Mail, the BuckeyeNet server checked his mailbox and forwarded its contents down the phone line. And there was Mr. D's reassembled picture gazing at him, none the worse for wear after his 4000-mile trip!