Hi and welcome to cyber. We got I t. My name's Anthony and I'm your local subject matter expert here for Network Plus And today we're gonna be talking about the OSC and T C P i p models.
So what is the OS I model? Well, the s I model is a way of thinking about networks that allows us to divide it into layers. Now, when we're talking about networking, we can think of networking in one overarching idea of sending communications from one point to another point sending our
traffic our data from one computer to another computer anywhere in the world. That's networking.
networking also divides itself into different layers that encompass different aspects of this transportation process. If we just thought of networking as one big overarching process and didn't have in a way to break it down into these different layers, it be harder to understand what goes on and be harder to understand
how the data is transformed, how the data is moved across the network
and how are different sessions air managed in controls and how our applications actually access the network. So we want to take a look at these different layers. We want to be able to dive into Roos I model, and we want to understand what each of these layers mean and how to understand them.
so what is the S I model do for us? What does it really mean? Well, let's compare this to the analogy of shipping a package. Now, if you would purchase a package online and ask for it to be delivered from the factory over to your house, this entire process is known as shipping.
just order something. They box it up, they send it on the truck. There's a lot of smaller processes involved, but we just encompass it in one grand turn term known as shipping the same thing with Roos I model.
We have all of these different processes that go on when we connect from one computer to another. We have all of these different. We have all of these different sub situations. We have all of these different management's and controls, but we just encompass them all in one term known as networking.
But if we were to break down our shipping process and then say we have a certain process where we're actually handling the item that we ordered and putting it or taking it out of the box. So we have the item that we ordered and taking it into or putting taking it out of a box.
And then we have another layer of shipping.
Where are box actually, is being loaded onto a truck for movement onto the road, and then we have another layer where the truck is actually in transit to our location. And then finally, we have another layer similar to
when we're boxing the truck, the the box onto the truck,
that same layers in play when we're taking the box off of the truck and then we're back to our first layer, where we were handling object when we take it back out. So
it's sort of all of these original steps to get the box to us now in reverse. We're taking it back off the truck. We're taking object out of the box. It's the same thing when we're thinking about the S. I model. The S I model allows us a way of breaking down that network into these steps that occur not just once,
but it will actually go back the other way. When we're breaking it, we're breaking our objects more, breaking our packets
back down to the way that we can understand them.
let's do a quick general overview of Roos I model and then talk a little bit about a way that we can remember the order. And then we'll go into the exact specifics of each individual layer.
So Roos I model is consists of 77 different layers layer one and layers all the way to layer seven layer. One is going to be our low. What we call our low level layers
and our layer seven will be higher. Higher level layers higher level in lower level, meaning
lower level being more basic root, more
bare bones type of transmission of data, such as on our layer one. We have our physical layer, so that's gonna be the actual physical electrical impulses and the cables and the network interface card in our computer, where's Layer seven is going to be at the application level, where
our computers managing what applications what programs
are allowed to use network connections are allowed to talk out over the network, so it's a higher late level of computing. It requires a lot more. Ah, lot more processes occurring in order for this layer seven process to be happening.
we have seven again. We have seven layers are layer. One is going to be our physical layer layer. Again, we mentioned that our physical layer is going to be our cables and our bits. Layer two is going to be our data link layer when we're talking about our data link layer. We're talking about things like Matt sending our Mac
address across a network,
sending to a switch or sending frames. Layer three is going to be on network layer when we use I P addressing when we're sending two points all across the world that we're sending to data to a router that would be our layer three level. Layer four is going to be our transport layer,
our transport layers going to provide us with management and help us to break into
break up our sessions into packets.
Layer five will be our session layer. Our session layer is going to be a communication and management of our actual communications sessions, basically dictating who's allowed to talk. How, who's allowed to talk win in order to help keep things a little bit meat and help
our communications between our two in points go smoother.
Then our layer six is going to be a presentation layer presentation. Layer is going to encompass things such as encrypting and decrypting. It's essentially going to format and prepare our data to be presented to us on screen or in a way, we as humans can understand. And then layer seven is our application layer,
and our application layer is going to be what
allows our programs to connect to our network. What a little allows and dictates what, what aspects of our computer and what aspects of our programs are allowed to communicate and are allowed to send data over our network and help to manage that.
we see how we go from very again a very low level, our physical layer, all the whip to our application layer, and well, after we talk about our way that we can remember, our order here will go into more detail on those individual layers. My favorite way to remember things, especially lists. It was going to be having a new moniker for something
for our own signed model There are a couple of new Monix out there.
layer one toe layer seven. While there are others that go the opposite way they go layer seven toe layer one I kind of like things going in numbers sequential order from low, at least greatest. So we're gonna do some new Monix going from layer one toe. Really? Or seven.
We have two new Monix here
and our new Monix are going Thio all need tohave p for physical D for data link in for network T for transport s procession pee again for presentation and then finally a for application.
Our first pneumonic is Please do not throw sausage pizza away. A very solid piece of advice now also applied to those all os I model
And then we have another which I was told people do not our don't need to see Paula Abdul So depends on your personal preference. Maybe you do or don't want to see her, but this will help you as well as the sausage, pizza, pizza piece of advice.
You can use these in order to help you remember the order of the O s I model in case
you get tend to get these words or phrases mixed up a little bit. So using our new monitor here and then by remembering that Roos I model is a way that we can break up the term networking the way that we can think about networking into different layers,
we can understand a little bit better about how our combat computers communicate with each other.