RelativeResourceManager44

RelativeResourceManager44 - CprE 530 Lecture 22 Topics...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon
CprE 530 Lecture 22 Topics Remote Access Telnet – Network Virtual Terminal (NVT) – Commands – Option Negotiation Rlogin X-Windows
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Telnet TELNET: a Virtual Terminal Protocol that provides interactive access to remote computers application The protocol defines: Terminal driver OS Terminal • Format of data • How control signals are passed and how to distinguish them from data • Data transfer mode (half/full duplex, sync/async) • How out-of-band signals are passed • How data delivery is controlled Telnet NVT – Network Virtual Terminal telnet client Psuedo application local char set local char set terminal terminal device telnet server Port 23 TCP/IP TCP/IP NVT char set Local charsets of different OS’s may not be compatible. When sending over the network, the local charset is translated to the common NVT charset by the telnet client. The telnet server then translates the NVT charset to the local charset OS OS
Background image of page 2
Telnet Telnet The virtual terminal consists of a display and a printer Display – Characters are 7 bit ASCII – Operates in scroll mode with unlimited line length, unlimited lines per page – Must be able to generate control signals – Must be able to generate control signals: Are You There Interrupt Process Abort Output Erase Character Erase line Break Printer – Has unspecified line width and page length – Can print the 95 ASCII graphic characters – Can respond to the control codes: NUL Line Feed Carriage return
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Telnet Telnet Commands Definition Abbr code End of subnegotiation SE 240 No Operation NOP 241 Data Mark: A stream sync character DM 242 Break BRK 243 Interrupt Process IOP 244 Abort Output AO 245 Are You There AYT 246 Erase Character EC 247 Go Ahead: turn line around for half duplex GA 249 Begin subnegotiation SB 250 WILL 251 WONT 252 DO 253 DON’T 254 Interpret as CMD IAC 255
Background image of page 4
Telnet Commands How to mix user data and commands: user data: 0 7 bit ASCII command: There is a special command to transfer 8 byte data 7 bits 1 Telnet Options Options can be negotiated by telnet processes New options can be accommodated since they are not part of the standard Three categories 1. Enhance, change, and refine NVT characteristics (e.g. line width) 2. Change transfer protocol (e.g. suppress GO AHEAD) 3. Information to be passed to the host (e.g. status, terminal type)
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Telnet Options
Background image of page 6
Image of page 7
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 19

RelativeResourceManager44 - CprE 530 Lecture 22 Topics...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online