Telnet Option Specifications (RFC0855)
Original Publication Date: 1983-May-01
Included in the Prior Art Database: 2019-Feb-14
Internet Society Requests For Comment (RFCs)
J. Postel: AUTHOR [+1]
This memo specifies the general form for Telnet options and the directions for their specification. This RFC specifies a standard for the ARPA Internet community. Hosts on the ARPA Internet are expected to adopt and implement this standard. Obsoletes RFC 651, NIC 18640.
Network Working Group J. Postel Request for Comments: 855 J. Reynolds ISI Obsoletes: NIC 18640 May 1983
TELNET OPTION SPECIFICATIONS
This RFC specifies a standard for the ARPA Internet community. Hosts on the ARPA Internet are expected to adopt and implement this standard.
The intent of providing for options in the TELNET Protocol is to permit hosts to obtain more elegant solutions to the problems of communication between dissimilar devices than is possible within the framework provided by the Network Virtual Terminal (NVT). It should be possible for hosts to invent, test, or discard options at will. Nevertheless, it is envisioned that options which prove to be generally useful will eventually be supported by many hosts; therefore it is desirable that options should be carefully documented and well publicized. In addition, it is necessary to insure that a single option code is not used for several different options.
This document specifies a method of option code assignment and standards for documentation of options. The individual responsible for assignment of option codes may waive the requirement for complete documentation for some cases of experimentation, but in general documentation will be required prior to code assignment. Options will be publicized by publishing their documentation as RFCs; inventors of options may, of course, publicize them in other ways as well.
Option codes will be assigned by:
Jonathan B. Postel University of Southern California Information Sciences Institute (USC-ISI) 4676 Admiralty Way Marina Del Rey, California 90291 (213) 822-1511
Mailbox = POSTEL@USC-ISIF
Documentation of options should contain at least the following sections:
Section 1 - Command Name and Option Code
Section 2 - Command Meanings
The meaning of each possible TELNET command relevant to this option should be described. Note that for complex options, where
Postel & Reynolds [Page 1]
RFC 855 May 1983
"subnegotiation" is required, there may be a larger number of possible commands. The concept of "subnegotiation" is described in more detail below.
Section 3 - Default Specification
The default assumptions for hosts which do not implement, or use, the option must be described.
Section 4 - Motivation
A detailed explanation of the motivation for inventing a particular option, or for choosing a particular form for the option, is extremely helpful to those who are not faced (or don’t realize that they are faced) by the problem that the option is designed to solve.
Section 5 - Description (or Implementation Rules)
Merely defining the command meanings and providing a statement of motivation are not always sufficient to insure that two implementations of an option will be able to communicate. Therefore, a more complete description should be furnished in most cases. This description might take the form of text, a sample implementation, hints to implementers, etc.
A Note on "Subnegotiation"
Some options will require more information to be passed between hosts...