All language subtitles for 3. OSI Model Network & Data Link Layer

Create it as is logical communication between the two.

And based on the application how it defined what type of traffic must be if a GP traffic the transport

layer will go ahead and build the information send that traffic off and rely on the session to keep

that session open as long as the tranced long as it needs to be so to speak.

And as long as this transport is transport Mayer is sending this information out guess what.

The session remains open.

The CCP traffic that he wants to do.

Going to create the CCP communication between the two and we are going to use secret numbers to guarantee

that our data is being delivered it's

now segmentation is important too because segmentation allows us to take this huge piece of data.

Break them up in chunks and give them identification numbers so that way if this data comes over here

but it's three first dim one then two to four.

He's able to take this and say OK this this goes here here's one.

And OK we have two two goes here.

And of course we have three and then we have four

so we get to put identifiers on these of stuff going on at the transport layer.

So the transport layer is its job.

Is to say look these little port numbers and I'm community I'm trying to communicate on if I'm using

TCAP that you seek with numbers to make sure my garron that I'm guaranteed traffic back the Forth this

is where I'm going to be segmenting my data.

It Up in the pieces and is also where I'm either going to be doing UDP or TCAP traffic in a nutshell

now the network layer the network layer.

This is an interesting layer.

The network layers job is to provide to make you provide its own IP address

information has been sent that would be the source IP.

End is also it's job is also to put the destination IP address and

this way when the router gets the information way down the way or every router that gets the information

doesn't matter how far down it is the very first router that gets its information guess what he's going

to look at the destination IP and he's going to make affording decision based on my destination IP.

And this is what I mean by routers sit and work at Layer 3 because the router only uses only cares about

the destination IP when it's doing forcing him from forcing decisions when it's making a forwarding

decision.

This destination IP is its main source of moving that traffic.

So if I have a router rodder one here and he has data coming in Router one and the destination IP

is telling the router okay for that destination IP and then you go this way and I say it's coming around

but it is telling the writer with the destination IP is.

But then the router uses a mechanism to define how do I get to that destination IP address which interface

do I use to get to that destination IP address.

And I how and that's how it works.

Let's let's let's repeat that traffic comes in the route of one things to the layer of free information.

Now we're learning in the onus on model it's going to have the source IP and the destination IP when

the router gets that information coming in Router one is going to say okay I'm looking at destination

IP great I have a destination IP which in Freestore I need to use to get out that to get to that destination

IP address.

Oh it's just warm right here.

So I'm a go ahead and for that packet out this interface or PAC or for that data out that interface

layer to this is where our switches are used.

Now remember our network layer uses IP addresses are matched our data link layer by layer 2 will actually

use MAC addresses.

So that means in this information we have a source Mac the destination MAC

know the physical layer job it's job is to take all this information because up here is actually the

data we need to actually get it right.

I mean that's really what we're looking for we're looking for data

yes the application might be sitting right here.

But there's lots of data I need to send when I go to yote yahoo dot com.

I've got lots of data give to give to that person.

Lots of it.

But I need to also add this information on with that.

Dana

now the physical takes the data and all this information presentation information session transport

network data link and converts this.

These ones and zeros to electrical signal that means we put that bad boy on the wire.

We call this serialization we're putting the day data on the wire and then these electrical currents

travels down there

and this is pretty much the basics of the overside model it gets complicated because people go into

real detail and I feel that the I model needs to be as simple as possible starting off so now I'll just

take a look at how data is built.

From the very beginning and let's go take a look.

And all this information over here that we got after everything I just spring to you.

Let's see how this is built out.

So the application layer

you can bring it right over to here so the application layer says what user defined user uses data from

the app.

Look at the user's data sets the app

let's think about that what I'm going into my Firefox with data my putting in there.

I'm putting in the journal there aren't you know there's not going to premier a CTP Colin calling for

Slash I'm sorry calling the shots for Slash yahoo dot com

if I'm sitting at that particular site and I type in Show me the Show Me the weather

that's data that I'm putting in so you started to see this this is where the user is sitting at the

application.

Give me data.

OK.

Show me a food delivery I want to find a place that delivers food.

This is data that you're putting in

not notice this concept I say right here or what they say.

I mean these things I get out of you know that I've learned and I'm passing it on from other people

have taught me which is I'm self-taught but it's still so and rewriting the books someone is writing

making the videos right.

So yeah I'm being taught just like you are now header information which is a header so a header something

that sits in front of the data

now some people write it this way saying you know that the head did that the data sits here and the

headers are sitting here at her and her information at her.

Some people like to write it this way.

Which is me.

I like to write it this way and I have my head or my header and my header.

Ok but when you're looking at this if I actually was going to sniff that data what a sniffy means.

So this means I'm actually grabbing the raw data that's going across the interface.

That's what sniffing is and if you look at that they know

it will be at a bottom to top formation.

So my data will be sitting here

then my

transport we'll be sitting here

them my network will be sitting here

them I didn't think we'll be sitting here

now this means and this type of transformation I'm not using I'm only using Layer 4 3 and 2

that then the physical layer are actually sent out onto the Y