One question that comes into our mind is OK now how does this guy talk to this guy and to this guy let's
say for example let's say let's see these two guys want to talk to each other to whatsapp Kline's they
want to talk to each other right.
So let me come to this particular.
So this client wants to talk to this client ok or something like this Klein wants Dr. Klein.
So two clients want to talk to each other they are both connected to the Internet but they're going
to talk why are the server right.
OK.
So how are they going to talk to each other.
They can talk to each other or a client which is connected to the Internet.
OK.
You need to talk to it.
Why are particular you call it as you know a particular address or something like that that in such
a way that they are identified.
Betsy For example if you are making a call from home to just as I say you are a client and you want
to request the shopkeeper instead of going to the shopkeeper's address you want to make a call and ask
the shopkeeper to deliver it to you.
Right.
Now comes the question.
OK.
How do I contact the shopkeeper.
Again I can contact the shop purchased by only one week.
What is a way that I can contact the shopkeeper I can contact the shopkeeper by knowing his phone number.
Right.
I know his phone number.
I ring his number he gets.
Now how does he know.
Where should he deliver.
Because I tell him my address so I have an address and I have his phone number which makes me contact
him and he can connect me right and he can get back to the same way.
We need some kind of an address if one client needs the service which is basically the client needs
to know the so-but IP to which he can talk to.
So he will say I want to talk to the server.
OK.
When I talked to the Zobel I am basically talking to a particular IP address.
Now the Sobol when you want to talk to another client OK you send to the server and the server sends
it to another client.
The service of also note should also know the client's IP addresses.
So you have to know the IP address of the client and the server.
Both of these things are very much you know are very much needed.
Say for example this client is stuck to the server.
So which means he should know the IP and when the soul wants it up to the client the server should know
the client side right both of them need to communicate with each other over the Internet.
So you require the IP.
So let's say for example you send a message from watch.
OK so ABC is sending do X Y Z and ABC sends Hi.
It goes to whatsapp.
So now from what subscriber it has to go to ex-Vice y phone so x y z is Faunus connected to the Internet
when X Y Z phone is connected to the Internet and it has an IP address.
Right.
X Y Z phone has an IP address now an x y z phone has an IP address.
OK.
It's why these phone has an IP address.
Can I say because X Y Z phone has an IP address.
Can I say that I can reach my message from the server to X Y Z by giving his IP address.
My message can reach Tula's phone I can reach the x y z that is the list for each because every phone
is Scarecrow's to every phone.
The internet is compressed by its IP address.
But now comes the question how can we ensure that the message reaches whatsapp on his phone.
What is the message which comes from Whatsapp server comes to this phone because of the IP address but
it lands up in Facebook app.
It's not a good thing right.
It should land in whatsapp in whatsapp client right in that WhatsApp application.
It should not land up in in something else.
Right.
So that's something which is very important.
If let's say you send a message to the wall and the Soval when he sends a message to the WhatsApp to
watch up on the phone.
IP address is only sufficient to reach the phone idea or vision to reach the phone.
But if you want to reach from the phone if you want to reach an application a particular application
on the phone you require something more than an IP address and that more than the IP address is Scalzo
or number.
OK.
So it requires two things.
First is you require IP address and four application for each applications to each applications you're
required Fortnum let's say for example when I see Google got good art in OK when I request the Google
server I am requesting Google server but Google all by default OK is at a port the port there is less
HD.
The port is called as a deep.
So when you write to port 80 you know that's Bideford.
You know he's at Port 80 so by default it's not shown.
So even if you don't write anything collinearity it is actually by default calling port number.
That is what it should be a request to do.
But if you write that letter call in it and it will never give you a response back.
Why.
Because Google server is not that is not at fault.
What it said it does so if you're right for AT&T.
OK so let us for ADHD knifer say 80.
OK.
Scotch Dublin
18N into all OK.
Collinearity
So he's got a bit stubborn on that.
So.
So you can get.
You can get.
So basically the part number generally which was that active requests are being directed to work for
it.
OK.
So these are a few things that you need to remember when we understand the client server model.
Correct.
OK.
And so there are two things that are required as we understand from you we require the IP address and
the port number of calls we want to send in detail as we program.
OK.
So now we can open a pie chart and start with our programming.
Let's begin from the next.