Networking Basics:

Let’s say you are at your home with your PC, and you have typed www.google.com in your browser (for example Internet explorer or Google Chrome) and hit enter. Now, Google’s home page opened and you can search anything you want. That’s great!

Have you ever wondered how all these things work?

Well, that’s simple. Let me explain it.

Before we start discussing about how this works, we need to first understand some basic things.

What is an IP address?

Like we are identified by our names (for example Bob, John etc), In the same way a Computer identifies itself by a number. That number is called IP address. So, an IP address is nothing but a number which is assigned to a computer or any networking device, so that it can communicate with other computers or devices in the network.

Example of an IP address:  10.0.0.1 (Don’t worry, we will learn all about IP address shortly)

However, It‘s very difficult for us to remember the IP address of thousands of computers in the Internet. So, we have assigned a name to an IP address that we can easily remember. DNS(Domain name system) is a service which helps to translate from a name to an IP address.

What is a network?

Let’s say you have 5 computers at your home or in your office, and you want all the computers to communicate with each other. For this to happen, you need to connect all the computers to a special networking device called switch (don’t worry, we will learn all about a switch shortly).Now you have created a network, which has 5 computers and one switch.

So, Network is a group of computers or networking devices connected together in order to share data or files with each other. Internet is a collection of thousands of these networks.

Now, let’s come back to our earlier discussion. Below are the things that happen when we access Internet.

1. When we typed www.google.com on our web browser, the computer will take the help of DNS service to translate this domain name (www.google.com)to IP address(for example: 1.1.1.1).
2. Once the computer knows the IP address of google.com, it will make a 3-way handshake with the web server(www.google.com), as web service uses TCP as a transport layer protocol. Click here to know about TCP 3-way handshake. For this, our computer needs to exchange some packets with the server; and these packets need to pass through many networking devices (like router, switches etc.) in the internet. 
3. After the successful 3-way handshake, the computer will send a HTTP GET request(HTTP is a protocol, which is used for accessing web services) to the server; and the server will then respond with a HTTP response message(which contains the content of the webpage).
4. Then, Browser will display those contents in the screen, and we can see the Google home page.