COMMUNICATION
11 COMMUNICATION
Communication oftP client and server run on different computers using different Os, character sets and file formats o FTP must take this heterogeneity compatible ● Communication over O Control connection ○ Data connection
12 Communication ⚫FTP client and server run on different computers using different OS, character sets, and file formats. ⚫FTP must take this heterogeneity compatible ⚫Communication over Control connection Data connection
Communication over Control Connection o Uses the nvt ascii character set o Achieves the communication by commands and responses o Each command or response is a short line terminated with a two-character(CR+LF)end of-line token
13 Communication over Control Connection ⚫Uses the NVT ASCII character set ⚫Achieves the communication by commands and responses ⚫Each command or response is a short line terminated with a two-character (CR+LF) endof-line token
NVT TELNET TELNET Terminal client server 旦 Pseudot driver Internet Local computer nVt Character set Remote computer character set character set Figure19-5
14 Figure 19-3 NVT
Using the control connection Local Local code code Control NVTASCIL Control process Control process Client connection Server Figure 20-4
15 Figure 20-4 Using the control connection