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