How does the Internet work?
A high-level overview of the Internet
Published 25 Jul 2022
Have you ever wondered how the Internet work? The Internet is the backbone of what is now popularly known as the world wide web. Many services such as web, email, streaming video, and more are non-existent without the Internet. So let's get started with the Internet.
Internet is a massive topic, and there are graduate degrees about it. Hence this article will serve only as a high-level overview of the Internet.
Before we learn how the Internet works, we need to know what the Internet is.
What is Internet?
Internet, in short, is just a global network of network of. . . . of networks that connects more than 10 billion computers. You might be like, now what is a network? Let's try to understand it.
What is a network?
The network comprises two or more computers linked via cable to share and exchange files and resources. Let us try to understand this with an example.
So, your friend came over, and you wanted to connect your computers via a cable so that you could play a game. This is nothing but a network of two computers. Now for the same thing, let us assume that 10 of your friends came over and connected computers to play the game. This forms a network of 10 computers. But here rises a problem. We need about 45 cables for connecting ten computers, and that's a lot of wires. At this rate, it is practically impossible if we want to connect 10 billion devices.
To solve this problem, we introduce a small computer in the middle that will manage all the connections between the devices in a network called a router. So, now only one cable is needed for each computer to connect to the network.
Now, a cable can connect these routers with another network router that combines both networks. Similarly, as before, we can establish a primary router to connect other routers to form a network of networks. I hope you see where I am going with this. Now joining these networks creates a Network of Networks.
Internet is similar to the network of highways or freeways which connect the entire world. The content is sent using these highways to preferred destinations.
I hope you got an idea about what the Internet is. Now let us look at it in a bit more technical way.
The Internet is a technical infrastructure that enables billions of computers to be connected. They communicate with each other with TCP/IP. Transmission Control Protocol(TCP) and Internet Protocol(IP) are communication protocols that define how data should travel across the Internet. Protocols are nothing but a code of conduct between two parties so that each of them understands the other actions. Protocols are set such that all the computers understand each other messages.
All these devices are essentially connected using cables. Yes, of course, I am currently connected to a WiFi network. Still, the WiFi router is associated with the Internet Service Provider(ISP) cable. These cables are connected to even more extensive networks that give access to the Internet. An ISP is a company that operates some unique connected routers and can also reach other ISPs' routers. So the message from our network is carried through the network of ISP networks to the destination network.
Above is a great map that shows the undersea cables that keep the Internet alive. It shows the sheer scale of the infrastructure which supports the Internet running. These cables are covered in protective shielding and run along the ocean bed. Data is sent between the wires as pulses of light.
Below is an image of an attempt to map a tiny subset of the Internet. The places where it looks like stars are small networks, and you can see how the networks are connected. This also represents the complexity of the Internet.
Till now, we have briefly understood how the Internet works. Now, with the help of a massive infrastructure like the Internet, we can run systems or services like the Web, email, IRC, streaming, and many more. To reiterate what I just said, the Internet is an infrastructure. In contrast, the Web, email, IRC, streaming, and many more are services built on the infrastructure. In a future blog post, we will dive into how the web runs on the Internet. But before we finish, let us look into the origins of the Internet, followed by some fun facts.
History of the Internet
The Internet started in the 1960s as a way for U.S. government researchers to share information. It was a research project by academic institutions to help the U.S. Defense Department share data stored in any computer, as the '60s were large and immobile. To make use of data stored in any one computer, one had to either travel to the site of the computer or have magnetic computer tapes sent through the conventional postal system.
Another catalyst in the Internet's formation was the Cold War's heating up. The Soviet Union's launch of the Sputnik satellite spurred the U.S. Defense Department to consider how it could still disseminate information even after a nuclear attack. This eventually led to the formation of the ARPANET (Advanced Research Projects Agency Network). This network ultimately evolved into what we now know as the Internet. ARPANET was a great success, but membership was limited to specific academic and research organizations with contracts with the Defense Department.
Now for some fun facts:
- Vincent Cerf and Bob Kahn are known as the co-founders of the Internet. This is because they have developed TCP/IP, which made communication between two computers possible.
- As of Jan 2021, there were 4.66 billion active internet users worldwide - 59.5 percent of the global population. 92.6 percent (4.32 billion) of this total accessed the Internet via mobile devices. (Source: Statista)
- Estimates are that the companies like Google, Amazon, Microsoft, and Meta(formerly known as Facebook) have data online storage of at least 1,200 petabytes between them. That is 1.2 million terabytes (one terabyte is 1,000 gigabytes). (Source: BBC Science Focus.)
- On Oct 29, 1969, at 10:30 in the evening first message was sent on ARPANET from one computer over a modified phone line to another computer hundreds of miles away.
- First, they sent only two letters, then the network crashed. But after some debugging, the remote connection was established between the computers for roughly after an hour.
If you want to dive deep into these topics, I suggest you visit MDN's articles on this.
Some more resources:
- Watch this BBC short for an overview of how the Internet works.
- Watch How the Internet Works in 5 Minutes.
And that's the end of this blog. If you learned something new, then be sure to share it with your friends. And if you feel something is wrong or something that something can improve, I am always happy to hear your thoughts. You can connect with me on Twitter at @gjdeep or comment down below. Your feedback will be appreciated.