Telnet Protocol specifications
The cover note that announced a new official TELNET specification and a phase-in schedule for it.
McKenzie, A.M., "Telnet Protocol specifications", RFC 495, DOI 10.17487/RFC0495, May 1973, <https://www.rfc-editor.org/info/rfc495>.
@misc{rfc495,
series = {Request for Comments},
number = 495,
howpublished = {RFC 495},
publisher = {RFC Editor},
doi = {10.17487/RFC0495},
url = {https://www.rfc-editor.org/info/rfc495},
author = {A.M. McKenzie},
title = {{Telnet Protocol specifications}},
pagetotal = 2,
year = 1973,
month = may,
} RFC text
Network Working Group A. McKenzie
Request for Comments: 495 BBN-NET
NIC #15371 1 May 1973
Categories: TELNET, Protocols
References: RFCs 318, 435; NIC 7104
TELNET Protocol Specification
Following much discussion of TELNET via the RFC series, an open meeting
was held at UCLA on 5 March to formulate a new specification for the
TELNET Protocol. Two attached documents (TELNET Protocol Specification,
NIC #15372, and TELNET Option Specifications, NIC #15373) report the
results of that meeting, which was attended by: Alex McKenzie, BBN-NET,
co-chairman; Jon Postel, UCLA-NMC, co-chairman; Bob Braden, UCLA-CCN;
Vint Cerf, Stanford University; Bernie Cosell, BBN-NET; Dave Crocker,
UCLA-NMC; Steve Crocker, ARPA; John Davidson, Univ. of Hawaii; Gary
Grossman, Univ. of Illinois; Bob Merryman, UCSD; Lou Nelson, UCLA-NMC;
Mike Padlipsky, MIT-MULTICS: Milt Reese, FNW; Bob Thomas, BBN-TENEX;
Steve Wolfe, UCLA-CCN.
The two attached specifications referenced above have been reviewed by
the meeting attendees, and should be viewed as the "official" TELNET
Protocol (subject to the implementation schedule given below).
Nevertheless, these documents are still subject to minor revisions and
any pertinent comments should be addressed to me at the NIC as AAM, or
by mail at:
Alex McKenzie
Bolt Beranek and Newman Inc.
50 Moulton Street
Cambridge, Ma. 02138
There are two key dates for a phasing in of the new protocol: the
date when sites should feel free to send the "new" form of TELNET
commands and special codes without expecting to receive "error"
responses, and the date when sites may remove the code which
processes the "old" form of TELNET commands. Between these two
dates, sites may gradually implement and test the "interpreter" for
the new commands. It was the sense of the meeting that appropriate
lead times to these two dates were about 60 and 260 days.
Accordingly, these two dates are hereby established as 1 July 1973
and 1 January 1974.
I have also attached specifications for TELNET options which allow
negotiation of:
o binary transmission
o echoing
o reconnection
o suppression of "Go Ahead"
o approximate message size
o use of a "timing mark"
o discussion of status
o extension of option code set
These specifications have been prepared by Dave Walden (BBN-NET) with
the help of Bernie Cosell, Ray Tomlinson (BBN-TENEX) and Bob Thomas;
by Jerry Burchfiel (BBN-TENEX); and by David Crocker (ULCA-NMC). It
appears that these options cover most of the capabilities of the
current version of TELNET, with the exception of "Hide Your Input."
Dave Walden has also promised to specify the following options in the
near future:
o NVT printer line width negotiation
o NVT printer page size negotiation
o negotiation of the mapping between the line terminator
character available on a physical terminal (e.g., LF,
CR, NL) and the NVT characters to be transmitted
(e.g., CR NUL, LF, CR LF).
Dave has also announced his intent to seek collaboration with
Gary Grossman, Bob Braden, and perhaps others in defining an
EBCDIC option. The announcement of intent to specify these
options should, of course, be seen as useful information rather
than as the granting of an "exclusive right" to Dave, or any
other author.
I gratefully acknowledge the assistance of Bernie Cosell
in the preparation of the protocol specification.
AAM/jm
Attachments
[ This RFC was put into machine readable form for entry ]
[ into the online RFC archives by Gottfried Janik 4/98 ]
AI ELI5
On this page
§1The Meeting and Its Documents
Alex McKenzie of BBN reports that an open meeting at UCLA on 5 March formulated a new specification for the TELNET Protocol. It was co-chaired by McKenzie and Jon Postel, and the RFC lists the attendees.
Two attached documents carry the results: the TELNET Protocol Specification (NIC #15372) and the TELNET Option Specifications (NIC #15373). The attendees reviewed them, and they should be viewed as the official TELNET Protocol, though still subject to minor revisions. Comments go to McKenzie at the NIC.
A room full of experts agreed on the rulebook. This note is the cover page, and the rulebook is attached.
§2Phasing In the New Commands
There are two key dates. After the first, sites can send the new form of TELNET commands and special codes without expecting error responses. After the second, sites may remove the code that handles the old form. In between, sites gradually implement and test an interpreter for the new commands.
The meeting felt that lead times of about 60 and 260 days were appropriate, so the dates are set at 1 July 1973 and 1 January 1974.
Everyone gets time to switch. First a date after which the new words are safe to use, and a later date after which the old words can be dropped.
§3The Option Specifications
The attached options allow negotiation of binary transmission, echoing, reconnection, suppression of "Go Ahead", approximate message size, use of a "timing mark", discussion of status and extension of the option code set. They were prepared by Dave Walden with help from several others, by Jerry Burchfiel and by David Crocker. Together they appear to cover most capabilities of the current TELNET, except "Hide Your Input."
Walden also promised to specify NVT printer line width, NVT printer page size and the mapping between a terminal's line terminator and the NVT characters to be transmitted, and intended to seek collaboration on an EBCDIC option. The RFC stresses that announcing intent to write an option is not an exclusive right to it.
Besides the main rules there is a menu of extras that two computers can agree to use, like echoing what you type, and more extras were promised.