Computer Networks: A humble Introduction

📡Disclaimer: A lot of concepts in this subject are interlinked, so it is completely okay to not understand every bit of jargon thrown at you in this post. The aim is to get the big picture overview.

A textbook definition 📚

A computer network is a group of computers that use a set of common communication protocols over digital interconnection to share resources located on or provided by network nodes.

Of course, you are bamboozled by the definition 👀🥴 Let me break down the terminology,

1. protocol - rules that are needed to be followed while communication/sharing of resources.
2. digital - meaning data/resources/message is transferred in the form of 0s and 1s.
3. network nodes - various devices that make up the network, for eg: your computer is a node as it is connected to the Internet( a network of networks! ). It is like an endpoint or redistribution point of communication.

This all might sound boring so let's understand the working of a real computer network at a high level,

How does a simple computer network work?

Let's say you are in some network. (most probably your SIM operator's or wifi's network ).

Your computer is host1 and it has a chrome( browser ) process running inside it.

Say this process wants to go to GOOGLE. So we typed www.google.com in the search bar and pressed enter.

Our modus operandi would look something like this,

1. Reach google's network - a network somewhere in the US in which google server (host2) is located.
2. Then after reaching that network in the US, we need to reach host2 - the server itself.
3. And finally, we'll need to reach the process in host2 which returns google.com's web page.

So, we aim is to get Network ID - to reach destination network, Host ID - to reach destination host and port number - to reach destination process

We don't need to worry about port no. because for some standard services like web service, it is fixed.( 80 for HTTP, 21 for FTP ). Thus for most well-known services, they are already defined.

And to get NID and HID, we need to convert the domain name into a special type of number: Internet Protocol Address short for IP address because IP address contains the two parts that we need, NID and HID. This conversion is done by the DNS-Domain Name System/Service provided by your ISP.

In the next post, we shall discuss more about these so called IP addresses :)