P2P File Sharing

Has any one thought of how does peer to peer file sharing takes place here we go...

We have many peer to peer file sharing sites such as torrents which accounts for more traffic than any other application including the web on the internet.

A peer is nothing but a PC connected to the centralized server.

There may be as many peers as possible. Let first tell you how does it works.

Let us take an example of a person X who searches for a particular file and when get it file transfer takes place from a person say Y who has the required file.

See the figure below:-

Here is the working :-

1) Lets say a person X wants a file named "Book on Web".

2) Now what X will do is he will connect to the internet and check in the centralized server as to which peer having this file is available.

3) Now X can see many peers having this particular file so X can from a particular peer so that X can download at good speed.

4) If X request from the peers say Y, a direct  TCP connection is established  between X's PC and Y's PC and the file is sent from Y to X.

Now lets see what happen when peer Y disconnects from the internet?

When Y disconnects when the download or the file transfer is taking place then the remainder of the file is obtained from another peer that has the file.