How the Internet Works
Introduction
“An Interesting fact - As of October 2024, there were 5.52 billion internet users worldwide, which amounted to 67.5 percent of the global population”
Internet is simply flow of data from one system to another. It is a vast network that connects computers all over the world.
Have you ever wondered what happens when you type a website URL, like youtube.com, into a browser's address bar such as Google Chrome ?
If not, don’t worry—I'm here to explain it in a simple way.
Simplified diagram of how the internet works
What Happens When You Enter a URL in the Address Bar ?
Let’s say you open your browser and type youtube.com into the address bar. If you’re familiar with IP addresses, that’s great! But for now, let’s put them aside.
Router can’t redirect you to youtube.com without knowing its IP address. Think of an IP address like your home address. If someone asks where you live, you might give them your home's name or identity. But without details like your state, postal code, or country—your exact location—they wouldn’t be able to find you. Similarly, a router needs an IP address to direct you to the correct server.
So, this is where the concept of DNS comes in. When you enter a website URL, the browser first sends a request to a DNS server, asking for the IP address associated with the requested website. The DNS server then looks up its database, finds the IP address linked to the website, and returns it to the browser. This process of finding the IP address is known as a DNS lookup.
Now that the browser has the IP address for youtube.com, it redirects the user to this address and establishes communication.
You might be wondering how the DNS knows which domain corresponds to which IP address. I have explained the internal working of DNS in detail in another article.
Working of Internet
Imagine the internet as a giant network of roads.
Internet: This is the whole network of roads, connecting cities and towns all over the world.
Packets: These are like letters or packages that you want to send. They contain the information you want to share.
Protocols (TCP/IP, FTP, HTTP): These are like different types of vehicles or delivery services. Each has its own rules and ways of moving things around. For example, TCP/IP is like a big truck for carrying lots of information, while HTTP is like a smaller car for delivering web pages.
Switch: This is like a traffic signal or roundabout that directs packets to the right road.
Router: This is like a GPS or map that helps packets find their way to the right destination.
ISP (Internet Service Provider): This is like a delivery company that connects your home to the internet highway. They provide the "road" to your house.
DSL, Satellite, 3G/4G: These are different ways to connect to the ISP, like different types of roads leading to your house (DSL is like a regular road, satellite is like a plane, and 3G/4G is like a high-speed train).
HTTP Request: This is like you asking for a specific website or webpage.
WWW: This is like the destination you want to reach, the website you're trying to visit.
So, how does it work?
You want to visit a website: You're like a person who wants to send a letter to a friend in another city.
Your computer sends a request: Your computer sends a small letter (HTTP request) asking for the website.
The request travels through the network: The letter goes through the local roads (your home network) and then onto the big internet highway.
The website is found: The letter reaches the destination city and finds the friend's house (the website server).
The website is sent back: The friend writes a reply and sends it back to you.
You receive the website: The reply travels back through the network and you see the website on your screen.