Linux Tutorial Series

Linux Tutorial Series – 164 – Computer networks – the very basics

Here is the video version, if you prefer it:

Today let’s talk about the very basics of computer networks.

First of all, let me say that the field of computer networks is very vast. I had 2 college courses dealing with computer networks and I feel like we barely scratched the surface of the topic. So what I will do is try to introduce you to all of the concepts in computer networks we will need to understand the commands that will follow and no more. I will also be relatively broad in my descriptions and will not nitpick the details; again, just enough knowledge to cover the later commands. Computer networks could warrant a post series in it of itself and I would have to do it after extensively reviewing the subject matter.

A computer network is consisted of layers. Each time you are sending some data over a network, your data has to pass through these layers in your computer, and, at the destination computer, it also has to pass through the same layers, but in reverse order.

Each layer has a different function and addresses different concerns. There is a layer we are particularly interested in, called the network (or the internet) layer. On this layer, each device connected to a network has its own unique IP (Internet Protocol) address. This enables network devices to communicate with each other – they address each other using IP addresses. When sending data over a computer network, that data is most likely chunked into little pieces. Each one of these pieces traveling on the computer network is called a packet. Packets travel through the nodes of the computer network until they reach its destination. Packets are forwarded by routers, a piece of network hardware that routes packets to where they should go in order to reach their destination.

There is a difference between IP addresses – there is your local IP address, which is what computers within your local network use and there is your global IP address, unique to you globally. Think of it like this – if someone in your house wants to talk to your computer via a computer network, it uses the local IP address. If, on the other hand, someone wants to talk to your computer outside of your house, they have to globally address you. The same way when a family member calls your name – you know they are calling you. However, if you are to receive a letter from the police station and someone uses your name, they will use your full name, or even some identification number unique to you, so you can be sure that they are addressing you.

I think we have all it takes to look at some of the most basic network commands. Let’s take a look at them in the following posts.

Thank you for reading!