How the Internet Works

Sample Lesson - Introduction

Lesson 1.01: What We Mean When We Say "The Internet"

"Then all the words I wrote get sent through a little tube to Iowa, where my granddaughter lives. And that's how the internet works, Ralph."
(Source)

When grandpas say "the internet," they could be referring to virtually anything. They could be talking about their email account (AOL, of course). They could be talking about the CD-ROM greeting card program they use to make those homemade birthday cards they mail out every year (with a generous $5 bill tucked inside). They could actually be talking about the internet.

Hey, even a broken clock is right twice a day.

Meanwhile, you go online every day to

• watch Netflix.
• take a math quiz.
• Instagram your Belgian waffle-style crepes.

If a roving band of grandpas surrounded you in the darkened alley behind a Golden Corral and demanded to know what the internet is, could you answer them? It's not as easy as it seems. In fact, maybe we've been too hard on grandpas all these years.

To truly understand how the internet works, you need to know what's under the hood. What is the internet? What parts make it work? What's the difference between the web and the net?

Yep, there is a difference. And, contrary to what that gang of hungry grandpas says, it has nothing to do with fishing.

Sample Lesson - Reading

Reading 1.1.01: No, the Internet is Not a Bunch of Tubes

The internet is a massive, global computer network. Technically, all it takes are two linked computers swapping resources to make a network, though, so when you and BFF link your vintage Game Boys up with Game Link Cables to play The King of Fighters '95, you're a network.

Congratulations to you both.

All Networks Aren't Created Equal

If all the computers in your house are linked via Wi-Fi, that's a network, too—more specifically, it's an example of a local area network, or LAN, because all the computers are in close proximity. The internet is an example of a wide area network, or WAN, because it connects a bunch of LANs together. In other words, it's a network of networks.

Think of it like the highway system…minus all the Taco Bells and fireworks stores. Instead of moving vacationing families, FedEx packages, and tons of frozen peas like the highway, the internet moves one—and only one—thing: data.

It doesn't matter what this computerized info contains; all the internet is interested in doing is moving it from Point A to Point B. E-mails, Snapchat videos, webpages; none of that matters to the internet, just like the highway isn't specially designed for use only by Nissan Altimas.

The fact that the internet is just one basic—albeit humongous—network is what's so awesome about it. Because it doesn't play favorites, we can run all sorts of applications on it, from Skype to SoundCloud to the World Wide Web.

You read that right: the World Wide Web and the internet are not the same thing. No lie.

Where the World Keeps Its Digital Stuff

The World Wide Web is the massive collection of, basically, stuff that you can send back and forth using the internet: photographs, videos, songs, emails, animated gifs of Michael Jordan crying, and pages and pages of text just like this one right here.

All this stuff is linked together using hypertext links that transport you from one page to the next and the next and the next…until suddenly it's 4:00 a.m. and you have no idea how you got to this riveting YouTube video about how ricotta cheese is made when you originally wanted to find some fun facts about James Fenimore Cooper for your Lit class presentation in—oh hey—five hours.

All that content has to be stored somewhere, and that's where servers come in. Servers are computers that store files, which, fittingly enough, makes them the file cabinets of the internet. Your emails are stashed in a server, for example. Maybe you have your PlayStation saves backed up online; those save files are stored in a server. Your home computer is a client. Ditto for your PlayStation. You use them to access information on servers.

Your home computer can be a server, too, like when you send your BFF that hilarious picture of a dog dressed as Andy Warhol that you took at the park this afternoon. In that set-up, your computer's the server because the photo is stored on it, and your friend's computer is the client because she's using it to access your rad photo. When two computers share resources equally like that it's called peer-to-peer sharing.

No matter if we're talking about peer-shared puppy pics or your Gmail account, most data is whisked from location to location along the internet using packet switching, which is where what you're sending gets broken up into a bunch of little pieces called packets (duh) that travel separately to their final destination and then get reassembled. It's kinda like WonkaVision, but with computerized information instead of candy bars and a tiny Mike Teavee.

Every computer on the internet (yes, even Beyoncé's) has an Internet Protocol (IP) address that identifies it so the packets know where to go. It's just like how your house or apartment has a street address so the Antonio's Pizza guy knows where to deliver all those Avocado Quesadilla pies. The big difference is that your computer's IP address is a bunch of numbers separated by colons or dots, not 402 West Bufflehead Street.

Play That Data Loud and Fast

Packet switching is a huge improvement over its predecessor, circuit switching, which is what dial-up networks use. In circuit switching, data travels in one big piece down one continuous route through the phone network. Because it's one large hunk of data, it moves more slowly, and because it sticks to one continuous route, it keeps that route blocked for as long as the data moves along it. That's why, if your home computer has a dial-up connection, no one else can use the phone; that data route's already taken up by whatever's coming and going from the computer.

You might think of the different ways data moves like the crowd at a Pentatonix concert at Madison Square Garden. Usually, all the fans travel to the show separately, enter the stadium through several different entrances, and make their way to their seats through a big network of aisles and rows. That's just like packet switching. In fact, the ushers that help people find their seats are just like internet routers that help packets find the fastest path from server to client.

If all 20,000 people traveled to Madison Square Garden together using the F train, then all filed into the venue using one main entrance, and all continued moving together throughout the venue in one mammoth line of Pentaholics as people peeled off at their seats, that would be like circuit switching. It would take for-ev-er—and those a cappella masters aren't getting any younger.

No offense, guys.

Sample Lesson - Activity

Activity 1.01: Getting It Done

The internet is one seriously well-traveled digital highway. It's like Route 66, but with more cables and fewer historic potholes. The internet is how Shmoop checks its email, updates its fantasy basketball team roster, and streams its favorite music.