What do you mean by FTP? Expalin in detail.

File transfer protocol (FTP) is the standard mechanism provided by TCP/IP for copying a file from one host to another. Transferring files from one computer to another is one of the most common tasks expected from a networking or internetworking environment.

Fig: FTP

Although transferring files from one system to another seems simple and straight-forward. Some problems must be dealt with first. For example, two systems may use different file name conventions. Two systems may have different ways to represent text and data. Two systems may have different directory structures. All of these problems have been solved by FTP in a very simple and elegant approach.

FTP differs from other client-server applications in that it establishes two connections between the hosts. One connection is used for data transfer, the other for control information (commands and responses). Separation of commands and data transfer makes FTP more efficient. The control connection uses very simple rules of communication. On the other hand, needs more complex rules due to the variety of data types transferred.

The client has three components:

·      The user interface

·      The client control process

·      The client data transfer process

The server has two components:

·      The server control process

·      Server data transfer process

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

The control connection remains connected during the entire interactive FTP session. 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. The two FTP connections, control and data, use different strategies and different port numbers.