How It Works

YouTube videos, Facebook profiles, Grandma's pictures, your kids' MP3s... all coming straight to you, wherever you are, from almost anywhere on Earth. That's the Internet. It's getting easy to take the Internet for granted, but step back, and think for a moment. How does all this magic work? What, exactly, is the Internet?

Thousands of networks that play nice together

The Internet's a gigantic collection of networks that all follow the same rules: rules which decide where they fit, and how they communicate with each other. (Nobody "owns" the Internet, but still it works - a fact that just might make you a bit more optimistic about the human race.)

At the top of the Internet hierarchy are a bunch of huge "backbone" networks that connect with each other at equally huge "exchange points." (The exchange point for the Western U.S. is named MAE-West: come up and see it sometime.) Regional networks connect into the backbone networks, and smaller, more local networks connect into the regional networks. (You connect to the Internet through an "ISP" - maybe it's a cable or phone company, maybe it's someone like Earthlink or NetZero. Those folks, in turn, connect to the rest of the Internet through one of the networks we just talked about.)

Zillions of packets, splitting and reconnecting

What's getting sent across the Internet? Tiny "packets" of data. You send an email message, and it gets split into small chunks, each headed for its destination by the best available route. (Chosen how? By a "router": a network device that specializes in doing just that.) If one packet can't get through, it gets re-sent over another pathway. That means parts of the Internet can break, and the overall Internet still works. (Hey, the people who thought this stuff up in the 1960s were trying to build networks that could survive a nuclear war...)

Somewhere close to the other end, all your packets are reassembled into your message (along with anything you've attached to it - pictures, video clips, documents, whatever.) The really amazing part: all this typically happens in just a fraction of a second.

Speaking the same language

You need to speak the same language as someone else to communicate well with them. The Internet uses shared, standardized languages, too. Many of them are called protocols. So, for example, there's a protocol for Internet "addressing," which allows each device on the Internet to send messages towards their destination, whatever it is. (Once upon a time, pretty much every Internet address corresponded to a computer. But more and more devices have Internet addresses of their own. Not long ago, Whirlpool and Microsoft tested Internet-connected appliances that could email you when the wash was done. Haven't seen that in the stores just yet, though!)

Speaking of getting your terms straight, some folks think the "World Wide Web" is the same thing as the Internet. It's not. The "Web" is a "service" that runs on the Internet, sort of like the way Microsoft Word or iTunes run on your computer. Plenty of other services run on the Internet, too: for example, email, and new telephone networks like Skype. Each of these networks follow the Internet's rules and languages, along with some of their own. (For example, the Web uses a "markup language" called HTML to tell your Web browser how each Web page should look.)

It's getting bigger all the time

Every day, the Internet gets bigger. By one estimate, at the end of 2007, more than 1.3 billion people were using it. And, since video and audio use far more capacity than old-fashioned text, the Internet's carrying far more traffic than ever before. For instance, YouTube wasn't even launched until 2005; by June 2007, it was churning out 27,000,000,000,000,000 bytes of data every month. That's 27 petabytes. How much data is there in a petabyte? Well, imagine a book one trillion pages long!