So in our last post, we covered the workings of TCP/IP and the OSI Model and how the layers link together. In this post, we will cover networking basics and answer another fundamental question, and that is “What is a computer network?”.
Before answering that, I would like you to imagine for a second that we are not living in the 21st century. Imagine a time when the only way of communicating outside of your general area was through pen and paper. Where you would have to wait for weeks or even months in order to hear back from someone. A time when wanting the see the latest news you had to go out and buy a newspaper. In this time you could also only listen to music whenever there were performances or perhaps on the radio.
That time is not so long ago, and it is thanks to computer networks that we are able to enjoy so many quality of life benefits at this very moment. It also goes without saying that it is thanks to computer networks that business is able to grow and expand and we also owe our thanks to computer networks for propelling our race forward into the digital age.
We have been connected in so many ways thanks to the power that networking has provided us. And I think that’s the main point of what a computer network is, it is what keeps us connected and without it, we might still be waiting for a handwritten letter from our loved ones.
So what is a Network?
Networking basics are two hosts being able to send and receive data between each-other, many times you will see the server/client relation. Think about what happens when you are trying to download your emails on your computer or phone, your “client” will begin the communication process using the TCP/IP stack to connect to the remote “server” and begin receiving or sending data. Once the connection closes you would have successfully downloaded or sent new emails.
So from the moment you form a connection what you learned in the TCP/IP and OSI Model post becomes applicable, I’ll try and break the process down from a packet capture in Wireshark (This is a useful application that will be discussed in a different post)
Looking at the packet capture and reading it from top to bottom we can see the TCP/IP stack at work.
1. A frame is built and transferred on the network port (Layer 1 Physical)
2. The source and destination mac addresses are added (Layer 2 Data-Link)
3. The source and destination IP addresses are added (Layer 3 Internet)
4. The source and destination port addresses are added (Layer 4 Transport)
5. Which application is being used (Layer 5, 6, 7 Application Layers)
Keeping this process in mind you now know what happens every time you try and download a mail, make a skype call, play a video game or even stream videos over the internet and it is this host-to-host communication that makes a network.
Before we end off this post I have one question for you.
Do you know what the world’s largest network is?
It’s the Internet, the world-wide-web, a collective of all our knowledge which has pushed our technological development forward hundreds of years and it is also thanks to networking.
You have now learned networking basics and how host-to-host communication functions. I would like to thank you for reading through this post and hope this has been informative for you, please sign-up to the mailing list for updates on any new posts and feel free to subscribe to my youtube channel where I will be posting these articles into vlogs.
Hungry for more?
Why not check out the follow-up post on switching
https://thenetworkberg.com/a-world-of-switching or if you need a refresher on the TCP/IP and the OSI model take another look at