If you are in school trying to learn how to become a good computer security engineer or if you are learning at home then this article is for you. It does not matter which part of computer security that you are trying to get into, you are always going to need to learn how networks work. In the past it was not as crucial because a lot of the computers that were out then did not connect to any devices that you needed to worry about. But that has changed and it is also the main reason why the computer security field is so big now. No one was expecting the internet to be the monster that it is now. Yes, during the 90’s a lot of people were able to see the potential of the internet but I am pretty sure that it has grown to surpass even their expectations. The internet is all over the place now and that means that networks are all over the place as well.
When people think about networks they tend to think of it as only a place where the data that you need from the internet comes from. Or they tend to think of it as the way they are able to communicate with fellow office workers in big corporations. But if you really get a good look at what makes the modern day network then I am pretty sure that you will be surprised. There are a lot of complex pieces to the modern day network. There are a lot of layers that most people do not know about and it is when you study them that the modern day network really starts to become fascinating.
The OSI model
First of all, when you are talking about the seven layers of the network you are talking about something that is known as the OSI model. The letters OSI stand for Open Systems Interconnection. These are the standards that are set so that the different networks from around the world are able to talk to each other when they choose to. If you did not have this standard then all of the networks from around the world would be incommunicado with each other.
The seven layers of the modern day network are known as:
- the Physical layer,
- the Data Link Layer,
- the Network Layer,
- the Transport Layer,
- the Session Layer,
- the Presentation Layer and
- the Application Layer.
All of these layers work together to deliver your information packets in a neat and fault resistant pattern. The layers, in the order that we put them in, go from the hardware of the machine to the operating system level of the machine.
But here is a secret about the layers that I just mentioned, not all of them are used on every network. As a matter of fact some simple networks that deal with the internet only use 5 of the 7 layers that are available. They use the Physical layer of course, the Link Layer, the more than obvious Internet layer which is really a condensed version of the Network layer, the Transport layer, and the Application Layer. So as you can see, not all of the layers are needed to be able to make a very effective network. One of the biggest networks in the world, the internet, only uses five.
So as you can see, if you are going to get into computer security, then knowing about the seven layers of the modern day network is advisable. If your attacker knows more about your network than you do then they will be able to sneak in any way that they want.