Telnet SUPDUP-Output option (RFC0749)
Original Publication Date: 1978-Sep-01
Included in the Prior Art Database: 2019-Feb-14
Internet Society Requests For Comment (RFCs)
NWG/RFC 749 BSG 26-Sep-78 13:13 45499 Network Working Group Bernard Greenberg Request for Comments 749 MIT-Multics NIC 45499 18 September 1978
Telnet SUPDUP-OUTPUT Option
1. Command name and code.
2. Command meanings.
IAC WILL SUPDUP-OUTPUT
The sender of this command REQUESTS permission to transmit SUPDUP-OUTPUT format messages over the TELNET connection.
IAC WON’T SUPDUP-OUTPUT
The sender of this command STATES that he will no longer send SUPDUP-OUTPUT format messages over the TELNET connection.
IAC DO SUPDUP-OUTPUT
The sender of this command grants the receiver permission to send SUPDUP-OUTPUT format messages over the TELNET connection.
IAC DON’T SUPDUP-OUTPUT
The sender of this command DEMANDS that the receiver not send SUPDUP-OUTPUT format messages over the TELNET connection.
IAC SB SUPDUP-OUTPUT 1 <terminal-parameters> IAC SE
The sender of this command (which must be the TELNET user process) is supplying information describing the capabilities of the user process’ terminal.
IAC SB SUPDUP-OUTPUT 2 n TD1 TD2 .. TDn SCx SCy IAC SE
The sender of this command, which must be the TELNET server process, is sending explicit screen control information to be carried out by the user TELNET process.
i.e., the SUPDUP-OUTPUT format messages may not be transmitted.
Greenberg [page 1]
NWG/RFC 749 BSG 26-Sep-78 13:13 45499 Telnet SUPDUP-OUTPUT Option
4. Motivation for the option.
The SUPDUP-OUTPUT protocol provides a means to access the virtual display support provided by the SUPDUP protocol (see RFC 734) within the context of a standard TELNET connection. This allows occasional display-oriented programs at non-display-oriented servers to take advantage of the standardized display support provided by SUPDUP. This cannot be done with the standard SUPDUP protocol or the TELNET SUPDUP option (RFC 736), for they both require that all communication after the negotiation to use SUPDUP has been completed proceed according to the protocol of RFC 734. This places upon the server total responsibility for screen management for the duration of the connection, which, by hypothesis, the non-display oriented server is not willing to accept.
User TELNET programs at display-oriented user hosts provide local screen management by mapping the NVT commands of TELNET into local screen management commands; often, this involves scrolling, end-of-page processing, line clearing etc. The SUPDUP-OUTPUT option allows a display-oriented application program at the server side to take over screen management explicitly, via the SUPDUP display control repertoire. TELNET remains in effect throughout. The IAC IP and other TELNET commands are still valid.
By means of the SUPDUP-OUTPUT option, display-oriented programs can run on the server host, and control the user host’s screen explicitly. The user TELNET process sends a description of the user terminal (as specified in RFC 734) to the server TELNET process as a subnegiot...