Introduction to Computer Networks – Part 2

Hello everyone, one more time, we are back after some time to continue our Introduction to Computer Networks.

If you remember from our last post on Introduction to Computer Networks – Part 1, we talked about what networks are and how they function.

Today we are going to continue our immersion into the world of Computer Networks, this time going a little bit deeper into the obscure waters of Network Protocols

Recap from the last post:

In the last post, we looked at what computer networks are, we also took a look into what are standards and protocols as well as we did a full view of the OSI model. Today we are going to learn more about protocols, specifically the TCP/IP protocol suite.

So let’s start our immersion:

What are Network Protocols?

Network protocols are like the rules and standards of communication.

Take for example the conversation between you and your friend.

You first need to agree on a language to be able to understand each other, then you must follow some standards of communication like proper grammar or say hi before starting to talk

Protocols can be group together in protocol suites

But what are protocol suites?

Cisco NetAcad Image

A protocol suite is no more than a group of inter-related protocols that are necessary to perform communication. There protocols suites are implemented by computers and other network devices

A Protocol stack shows how the individual protocols within a suite are implemented. This way we can look at them like layers, where each high layer depends on the one lower layer

An example of this is the image on the right, at the bottom ( the physical layer) we have 2 people, each has a voice that can pronounce words out loud, in the middle we have the rules ( language agreed upon)  and at the top are the actual words that can be spoken, this is the content of the message Let’s see some examples of network protocols


Now we have some idea of what protocols are but how do they interact with each other?

Network Protocols Interaction

Cisco NetAcad Image

Let’s take an example of a web server and a client computer interaction

If we go from top to bottom, we have HTTP, which governs the way a web server and a client(browser) interact.

This protocol defines the content and formatting of the request and the responses that are exchanged between the server and the client applications, and the same time HTTP relies on other protocols that govern how the message is transported

TCP is our next protocol in the list, this protocol manages the individual conversations between the client and the server by dividing the messages into smaller pieces, called segments

Segments are exchanged between the server and the client based on the TCP requirements of size and rate that the messages will be exchanged between server and client.

Then we have IP, the internet protocol. This protocol is responsible for taking those TCP segments and putting them in a package with an address and driving them to their destination

Then we get to the lower of the protocols, Ethernet, this one is a network access protocol that basically takes the IP packet and makes them possible to transmit on the physical cable

Protocol Suits and Standards

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There are many protocols suites out there, many of the protocol suites are created by specific vendors and will only be implemented on the equipment that those vendors create

  • TCP/IP
  • ISO
  • AppleTalk
  • Novel
  • Many others

But as we saw before, protocol suites are no more than a group of rules that govern the communication between devices.

But how do we create that group of rules? Well, we put different protocols together, but these protocols need to work with each other.

Let’s talk about the most used and open source protocol TCP/IP

TCP/IP

TCP/IP protocol suite as you can see on the image here is based on 4 layers, Application, Transport, Internet and Network.

Those layers have different protocols inside of them.

There are many protocols, but here you got some examples.

If you don’t know what DHCP or FTP means, please enter the name as you see on the screen in google and you will find a lot of info about them

What is next?

On the next post, we are going to talk about network devices like switches, routers and such and we are going to see on which layer of the TCP/IP protocol suite they are located and how they work.

Feel free to leave your thoughts on the comments as well as recommendations or suggestions

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