Explain the principle of FTP.

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 Solution :-

Diagram :-

Explanation: 

1. File Transfer Protocol (FTP) is the standard mechanism provided by TCP/IP for copying a file from one host to another. Figure shows the basic model of FTP.

2. The client has three components: user interface, client control process, and the client data transfer process. The server has two components: the server control process and the server data transfer process. 

3. The control connection is made between the control processes. The data connection is made between the data transfer processes. 

4. The control connection remains connected during the entire interactive FTP session. 

5. The data connection is opened and then closed for each file transferred. It opens each time commands that involve transferring files are used, and it closes when the file is transferred. In other words, when a user starts an FTP session, the control connection opens. While the control connection is open, the data connection can be opened and closed multiple times if several files are transferred. 

6. Separation of commands and data transfer makes FTP more efficient. FTP uses the services of TCP. It needs two TCP connections. 

7. FTP uses two well-known TCP ports: Port 21 and Port 20.


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