How does the Internet work
What is ISP, DNS, IP address
Browsing the web
What happens technically when we open up a web browser like Google Chrome, Safari or Microsoft Edge type in?youtube.com?and press enter?
We send a message to our?ISP?and ask it where to find?youtube.com.?ISP?stands for?Internet Service Provider, these are the companies we pay to so we can have internet access. In the US that is AT&T, Verizon, or Spectrum, in Europe that would be Telecom or Vodafone, and so on. Depending on your country you have different ISP companies that make money from internet usage.
So ISP gets our message asking for?youtube.com?and it sends that off to?DNS.?DNS?stands for?Domain Name System, which is basically a server matching website URLs (like?youtube.com) to their corresponding addresses.
DNS replies to ISP that?youtube.com?matches with 208.65.153.238 this address and ISP sends this address back to our browser.
These numbers that we received is an?IP (Internet Protocol) address, anything that is connected to the internet has its own unique IP address like your computer or your smartphone. This is used to identify devices on the internet.
Now that our browser knows the IP address of?youtube.com?it sends off another request to that address which is the address of the YouTube server.
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Servers?are computers located in data centers or server farms that store and send files when you ask for them. And with this request, our browser asks the YouTube server to return these files.
YouTube server responds to us with HTML, CSS, and JavaScript files. These are just text files that our browser will use to render?youtube.com?on our screen.
This whole process happens underneath the hood every time we open a website. However, since the internet is blazingly fast it happens in just a few seconds.
And if you know the IP address of a website you can directly search for it instead of typing?youtube.com. But in practice, nobody remembers the IP addresses of websites and there’s no point in it since everything is super fast.
What happens physically?
Let’s also understand what these requests mean in the real world.
We usually have a router in our house which gives us internet over wifi or cable. This router is connected to a modem installed in our house which allows the ISP to connect to it.
The modem sends a signal to wireless transmitters until it reaches the ISP, and then ISP connects to the world wide web using a physical cable.
What do we mean by the world wide web? These are physical cables that go to the bottom of the sea floor from your country to the Google data centers where the YouTube server is located.