0:00are a guys look into your sixteen computer networking tutorial
0:04and in this video one party has about 20
0:07s II model now the OS I motto is something that confuses a lot of people
0:12but it's actually incredibly useful model if talk directly
0:16for not only understanding how computer networks work but also specifically how
0:21to computers communicate with each other so if you had a hard time understanding
0:25you know
0:26the big picture of computer networking and how everything was kinda you know
0:30piece together
0:31with this models can do is now only give you a really good
0:34broader overview but it's also going to take the individual pieces
0:38in clarify how each part works par
0:41by part so what does is basically starts with the user experience basically you
0:47looking at your computer and explains everything
0:50all the way down to when you know those electric signals are traveling across
0:54copper wire to another computer
0:56so it does this in the form of layers
1:00now this model calls you know the different parts fit layers
1:04but the layers in this model are basically just different pieces
1:08I love how a computer network works now like I said it starts with
1:13you notice you your user experience you looking at the computer
1:16and first lawyers called application layer
1:23now this is basically software applications is basically the user
1:27looking at whatever program they have running on the computer now this layer
1:31usually you know involves things like Firefox arm
1:36you know Google Chrome those are you know probably the two biggest ones that
1:40users use whenever their networking and also you know whatever program you use
1:45for email and stuff it's basically software applications
1:49this is Lee again like I said closest to the user experience
1:54suffer applications or programs now the next layer is called
1:58presentation the presentation layer
2:03now this is the layer that your operating system works on
2:07now what this does is basically converts text that the user can understand
2:12like are you know letters in numbers
2:16because of course whenever you type something into your email
2:21your typing you know just basic letters and numbers
2:24a language that you can understand but that isn't the language a computer can
2:29understand
2:30your computer actually one of the languages that
2:33understands is something called ASCII
2:36and this is you know we'll talk about different you know languages stuff like
2:40that later on
2:41but this is basically a very simple arm language a computer can understand
2:46because
2:46you know it can understand English like you can it needs its own special thing
2:50so that's where your operating system does in this layer it converts text that
2:54the user can understand like letters and numbers
2:56to basically start that the computer can understand in
3:00it just makes it more easy to work with the data when it's in
3:03this former here now another thing that the presentation where does
3:07is also in crips data in whenever I see
3:10encrypts data I mean put a special code on it so that hackers
3:14you know just can't happen to instill your dad outlook you know what you're
3:18sending in your email and stuff like that
3:19we'll talk more about the presentation layer later on but just remember right
3:23now that it's the later that year
3:25operating system resides on now next layer is actually the
3:29session layer
3:32now if you're familiar with you know like PHP programming or anything like
3:37that
3:37then you already know what a session is a session is pretty much a conversation
3:41between
3:42to computers so what this layer does
3:45is you just go ahead or a conversation between
3:52to computers so
3:57whenever computers are in the process of having conversation with one another
4:01we call this conversation a session now this layer is responsible for you know
4:05starting
4:06in ending conversations or sessions it's also responsible for getting
4:11data from web say so with this say that you want to get data from web site
4:16this layer would go ahead increased section or start a conversation
4:20with the web server and whenever you know during the conversation it would
4:24help maintain the communication
4:26and if something you know disrupted your communication
4:29it will try to reestablish arm the link between and so you know you guys could
4:33still communique
4:35in whenever it was done this is the layer here
4:38that his response 44 ending the conversation so a session
4:41is basically like a conversation or communication between two computers
4:46and this gray here is responsible for pretty much starting
4:50ending in maintaining that conversation
4:53now the next layer I want talk about is called the transport
4:59transport layer and this
5:02will talk about what packets are later on but basically
5:06me give you guys a real you know quick overview in this is not
5:10technical definition so please I don't wanna get you know thousand comments
5:13a pack is pretty much like a chunk of data that you deliver from one computer
5:18to another
5:19whenever you know you have email in you wanna send it to another computer
5:24we compute does is your it breaks up into smaller
5:27chunks of data just because it's easier for your computer to work with
5:30smaller chunks data rather than one big one
5:34so these trucks that are are she called packets
5:37an I sometimes use the word packin frame interchangeably but there is a
5:41difference I'll talk about that later on
5:43so basically what this does is it insures that
5:47packets are just very packets
5:50are delivered