File Transfer Protocol (FTPA
1 File Transfer Protocol (FTP)
CONTENTS · CONNECTIONS COMMUNICATION COMMAND PROCESSING · FILE TRANSFER SIMPLE FTP-Assignment
2 CONTENTS • CONNECTIONS • COMMUNICATION • COMMAND PROCESSING • FILE TRANSFER • SIMPLE FTP -- Assignment
File Transfer Protocols(FTP) o Transferring files from one computer to another o Using two connections between hosts OOne for data transfer OOne for control information o Three components for clients: user interface client control process and client data transfer process o Two components for servers: server control process and server data transter process
3 File Transfer Protocols (FTP) ⚫Transferring files from one computer to another ⚫Using two connections between hosts One for data transfer One for control information ⚫Three components for clients: user interface, client control process, and client data transfer process ⚫Two components for servers: server control process and server data transfer process
Note FTP uses the services of TCP It needs two TCP connections The well-known port 21 is used for the control connection and the well-known port 20 for the data connection
4 FTP uses the services of TCP. It needs two TCP connections. The well-known port 21 is used for the control connection and the well-known port 20 for the data connection
User interface Control connection Control Control process process TCP/IP Data transfer Data transfer process process Data connection Client Server The control connection remains connected during the entire interactive ftp session the data connection is opened and then closed for each file transferred Figure 20-1
5 Figure 20-1 The control connection remains connected during the entire interactive FTP session; the data connection is opened and then closed for each file transferred