Lecture 13: FTP

This lecture was about the File Transfer Protocol (FTP). The main purpose of FTP is to transfer files from one computer to another across a network. FTP was implemented to help promote the sharing of files, encourage use of remote computers, and transfer data reliably between different end hosts. You might think at first that transferring files between computers is relatively easy. However, different operating systems have different structures for handling files and could be drastically different from one another. FTP is responsible for handling all these issues to make the transfer seamless for the users.

When an FTP connection is made, two separate connections are established. One is for control information and the other is for data information. First, the control connection is established and the end hosts communicate with one another. When a request is made over the control connection for a file, the data connection is established and the data transfer occurs. As data is transferred over the connections, replies are also sent back and forth. Replies are only sent over the control connection and contain much information about the state of the transfer.

Trivial File Transfer Protocol (TFTP) is a simplified version of FTP. It was designed to be small and simple and able to fit into the ROM of a computer. TFTP is mainly used for bootstrapping diskless systems.