FTP User Interface and User Commands
The FTP command set provides a rich, complete set of instructions for implementing FTP. A human user could employ these commands to perform file-transfer functions directly with an FTP server. But to do this, the user must have an intimate knowledge of how FTP works. The user must know exactly which commands to send at which time, and in what order.
Gaining knowledge of internal FTP commands might be a reasonable assignment for an internetworking expert, but not for a typical TCP/IP application user. For this reason, the FTP protocol defines an additional protocol component as part of the user-FTP process: the FTP user interface. It provides three main benefits to the FTP user:
User Friendliness The FTP user ...