I have general question, Suppose I have two PC’s one is client PC connected with wifi router at New York and other is server PC connected with wifi router at California. Both PC’s are connected over internet. MSSQL running on the server PC

A scanner is attached to the client PC, The client PC running a software that reads the scanner's data and client PC sends data to the server PC over internet.

So what is happening, the data is transmitting from New York to California

• Client PC is talking with Wifi router (new york)
• Wifi router (new york) talking with wifi router (california)
• Wifi router (californiya) talking with server PC

I need to understand how data is transmitted in these three steps context of communication ?

 

You have the general idea. But your second step is way too simple.

The originating client has to provide the public IP address of the destination server. The router maintains a table of other routers to which it is connected. The data packet gets sent to one of the connected routers.

Note that the client had an internal IP address, which the router changes to its public/ external IP address. And you have to specify a specific port as well. The IP protocol adds a number to identify this conversation.

And when the originating router gets the data, it repeats this process, until the data packet ends at the server’s router. Hopping from one router to the next.

And the destination router sends the data packet to the server.

This is a simplification, just to give you an idea. Fortunately, most of this is automatically handled by your PCs and routers. All you need is to open a port in the routers and specify real internet addresses.

 

Hello,

Have a look in the links of the following pages:
Internet
TCP/IP

Wireless networking

Bertus

 

Hopefully there is no requirement for keeping the data private, since that is not part of the operation. Sort of private, but not really private. LIke a post card through the regular physical mail system.