Welcome to the Glad You Asked series, a shame-free zone where we tackle topics you’re too embarrassed to ask even your BFF about. Don’t worry, we gotchu.
I’m an internet addict. I got hooked on the stuff sometime in the early 2000s, and I haven’t gotten a proper tan since.
Like many of you, I spent most of my time online without really understanding what I was dealing with. As I got older and nerdier, I dove into the actual technology that connects all the laptops, smartphones and tablets of the world.
Turns out the question of what, exactly, the internet is isn’t that difficult to answer.
What is the internet?
The US government created the first iteration of the internet?—?then called ARPAnet?—?in the 1960s to facilitate communication in the event of a Soviet attack on America’s telephone infrastructure. While it’s changed quite a lot since then, the internet’s core function remains the same: ensuring that two or more machines can trade data.
So, when you ask, “How does the internet work?” what you’re really asking is “How do two computers use the internet to talk to each other?” To answer this, let’s talk about the physical nature of the web and work back.
At its most basic, the internet is just an enormous system of interconnected wires buried deep underground. Think of them like the roads you drive on every day. Every house in America is “connected” via a vast network of asphalt that allows you to go just about anywhere.
In the same way, your computer is linked up with every other internet-connected machine on the planet. The data your computer receives is “driven” to your location.
The really cool part about this is that the internet relies upon multiple “roads” to transport information. If you were driving to work and heard about a bad accident on your favorite route, you wouldn’t just sit and wait for the congestion to clear. You’d simply go down another road and avoid the crash altogether.
This is called redundancy, and it’s why the internet is such a flexible piece of technology. If data can’t move through one stretch of wire for whatever reason, it can choose another route.
It’s all about data transfer
Now that you know what the internet is, it’s time to figure out how it finds its way onto your computer screen. The best way to explain this is to compare it to sending a package.
Say your best friend, Joe, wants to build a jungle gym for his nephew. As luck would have it, you have one in your backyard that you don’t use anymore. You want to give it to Joe, but he lives across the country and you don’t have a car. To make matters worse, you have no clue what his address is.
Thankfully, there’s a post office in your town that gives fantastic deals on shipping. On top of that, the post office can figure out exactly where Joe lives if you can tell them his full name.
Here, the post office is your internet service provider (ISP), such as Comcast or AT&T. When you type something—say, “Google.com”—into a browser, you’re only entering the organization’s domain name. Your ISP connects you to machines that help you turn this domain name into what’s called an IP address, which you can think of like a physical street address. One of Google’s IP addresses, for example, is 184.108.40.206.
Back to our example. You’ve run into another snag: Sending the gigantic jungle gym in its completed form isn’t an option. The whole thing would never fit in a box, and you’ll need to break it down so the post office can send each piece individually.
The issue with this is that your good buddy Joe is an utter idiot who can’t find his way around a toolbox. So you decide to send detailed instructions on exactly what he needs to do to build the jungle gym, right down to the specific locations of the nails he’ll need to hammer in.
Like the post office in this example, sending an entire image in its completed form over the internet isn’t efficient. Your computer needs to break the picture up into bite-size pieces that are easy to send. We call these individual chunks “packets.” Packets don’t have to be sent together, which means they can take whatever “road” they want to reach their destination.
While breaking up data certainly makes the process easier, it forces the recipient machine to reconstruct the image by itself. A computer can’t intuitively piece together a picture like a human would put together a puzzle, so the recipient needs specific instructions, or “protocols.” These protocols tell the machine exactly what it needs to do to recreate the data that’s being sent.
So, you begin the process of sending the jungle gym. You break it down into individual pieces, attach instructions to each of them and give them to the post office. The post office then figures out Joe’s address and uses the roads to send each piece to him. When your buddy has every scrap of wood, he closely follows the instructions you gave him to rebuild an exact replica of the jungle gym that once stood in your backyard.
Congratulations! Now you know how the internet works.
But wait—there’s more!
Every time you send an image to one of your friends, it’s broken down, transported in pieces and then reassembled by the recipient’s machine, per protocols that match up with the ones built into your computer. The same thing happens when you request data, like when you try to watch a video on YouTube.
Of course, this process is way more complicated than what I’ve described. I glossed over the Domain Name System (DNS), and I didn’t even touch on how information is secured when it’s transported. Both of these processes are complex enough to deserve their own articles.
If you’re the kind of geek who gets excited about topics like this, check out Khan Academy’s Internet 101 course. It starts by fleshing out the concepts discussed here and then progresses to more complicated subjects.
The internet sure is complicated, but that doesn’t mean you can’t?—?or shouldn’t?—?take the time to understand it. It’s perhaps the most important innovation in human history. And I promise it’s interesting.