Truckers in Cyberspace: the real dirt on TCP/IP

Truckers in Cyberspace

Wouldn't it be weird if, when you moved to a different city, all of your boxes were sent on separate moving trucks?... two boxes loaded into the green truck, five into the yellow truck, three in the blue truck...

Strange idea, huh?

Well, believe it or not, that's how e-mail reaches its destination! It's true: sometimes a message is broken up into different packets (boxes, in our metaphor) and sent along different routes ... all because of something called TCP/IP.

What's TCP/IP?

Short for Transmission Control Protocol/Internet Protocol, TCP/IP is the set of rules or procedures which allows computers and networks to communicate over the Internet. TCP/IP breaks down data (the text of an e-mail message, for instance) into smaller packets, puts header information (address labels) on each packet, and then forwards those packets through the pipeline.

Then, when all those packets arrive at their destination, the host network or computer reassembles all the packets in their original order.

Why does the Internet go through so much work just to get a piece of e-mail from one person to another?

Let's go back to our moving metaphor. The movers don't care what's inside your boxes. To them, a box is a box is a box -- even if your beloved Elton John memorabilia might be inside. They move stuff across town and across the country day in, day out. If they stopped to care about what might be inside a particular box, they'd never get their job done!

Movers ARE interested in which boxes will fit on one truck and which ones should be loaded onto others. They're concerned about finding the best routes, and they regularly communicate about road traffic and other obstacles. If a certain stretch of the highway is jammed with traffic, truckers will alert other truckers to take another route and avoid the area. They do all that because their job is to get stuff from one destination to another -- safely.

So think of TCP/IP as the movers and truckers of the 'Net. You can sit at your computer for hours, composing the most delicious love letter of your life. Once you hit the SEND key, however, TCP/IP takes over. Its job is to get the letter to your beloved. The TCP/IP "truckers" might break the message up into different packets and send them separately in order to get the message to its destination quickly.

Pretty cool, eh? Packets are the building blocks of the Internet.