Report of the Protocol Workshop, 12 October 1971
Decisions and guidelines for protocol design from the October 1971 workshop
Postel, J., "Report of the Protocol Workshop, 12 October 1971", RFC 295, DOI 10.17487/RFC0295, January 1972, <https://www.rfc-editor.org/info/rfc295>.
@misc{rfc295,
series = {Request for Comments},
number = 295,
howpublished = {RFC 295},
publisher = {RFC Editor},
doi = {10.17487/RFC0295},
url = {https://www.rfc-editor.org/info/rfc295},
author = {J. Postel},
title = {{Report of the Protocol Workshop, 12 October 1971}},
pagetotal = 4,
year = 1972,
month = jan,
} RFC text
Contents
NWG/RFC #295 JBP 2-JAN-72 15:35 8355
Protocol Workshop Report
Report of the Protocol Workshop
12 October, 1971
By Jon Postel.
Introduction
This is a report on the decisions reached at the protocol workshop
held in conjunction with the Network Working Group meeting held in
Cambridge from 10 to 14 October, 1971.
The workshop addressed itself to protocols of four types: IMP-Host,
Host-Host, Initial Connection, and Process-Process.
IMP-Host Protocol
The idea of IMP provided status reports to be exchanged via new
IMP-Host protocol messages was discussed and rejected because it was
felt that the level of state information which could be reported was
not sufficient to be worth the trouble of implementing this mechanism.
Host-Host Protocol
The Host-Host Protocol was discussed and several problems were brought
to light, among them were the following listed together with the
group's recommendations.
The GVB - RET mechanism may prove useful sometime in the
future so it will be retained though no one appears to be
using it now, however spontaneous RET commands are
explicitly prohibited.
The ECO - ERP commands are useful and should be supported,
but spontaneous ERP commands are explicitly prohibited. A
further restriction is that a second ECO will not be sent
until the first ECO has been answered. Note that any of
the following may be an answer to an ECO: ERP, RST,
"Destination dead", or "Incomplete Transmission".
The RST - RRP commands are useful, but the proper use of
these commands for determining the status of host software
is still open for discussion (please direct comments to Jon
Postel), however spontaneous RRP commands are explicitly
prohibited.
NWG/RFC #295 JBP 2-JAN-72 15:35 8355
Protocol Workshop Report
The problem of unmatched CLS commands are discussed and four
"solutions" were proposed:
Hold forever
Send a RST and clear the entry
Clear the entry and possibly mess up a future connection
Assign socket numbers in a sequential fashion to reduce
the possibility of confusion and clear the entry.
Note that the first two suggestions follow the protocol while the last
two do not.
The idea of flow control on the control link was suggested. A Request
for Comments is to be prepared exploring this idea more fully.
The usefulness of the ERR command is compromised if the receiver
mearly throws it out. Thus ERR's are to be logged, if at all
possible, and checked out with the sending site.
The NCP document should make clear the implications of queueing or not
queueing STR & RTS commands.
Initial Connection Protocol
The Initial Connection Protocol (ICP) was discussed and found to be
satisfactory however the following points were stressed:
The socket number sent by the logger (S) must be in
agreement with the socket numbers used in the STR & RTS
sent by the logger.
The implications of queueing or not queueing of RTS & STR
commands should be made clear in the ICP document. This is
particularly important if the user chooses the "listen"
option.
NWG/RFC #295 JBP 2-JAN-72 15:35 8355
Protocol Workshop Report
Telnet Protocol
The Telnet committee has been reactivated to consider the following
problems:
Clarification of the terminology half duplex, full duplex,
character mode, line mode, ASCII, and echoing.
Clarification of the end of line convention. Especially to
answer the question "Should there be a special end-of-line
character?"
Clarification of the conditions for leaving Hide-your-input mode.
Clarification of the operation of Break and Synch.
Specification of a server-to-user Synch.
Clarification of the definition of the Network Virtual Terminal.
Preparation of a new document defining the Telnet protocol
with the above improvements.
The protocol workshop did agree that:
It is the servers option for disconnection to imply logout
or not.
It is the servers option for logout to imply disconnection
or not.
Extra characters used locally to fill the time for format
effectors to take effect should not be sent over the
network
Synch means to examine the data stream from the current
point to a data mark (x'80'). If any break type characters
(e.g. etx, sub, Break) are found they are to have their
normal effect.
Upper and lower case are to be available to all Telnet users.
Data and File Transfer Protocol
The Data and File Transfer Committee will report separately.
NWG/RFC #295 JBP 2-JAN-72 15:35 8355
Protocol Workshop Report
[ This RFC was put into machine readable form for entry ]
[ into the online RFC archives by BBN Corp. under the ]
[ direction of Alex McKenzie. 12/96 ]
AI ELI5
On this page
§1The Protocol Workshop
On October 10-14, 1971, the Network Working Group held a protocol workshop in Cambridge to address issues in four types of protocols: IMP-Host, Host-Host, Initial Connection, and Process-Process. Jon Postel led the effort to document the group's decisions and recommendations for resolving practical problems that had emerged during implementation and early use.
Experts gathered to talk about how the network worked and fix problems they had found.
§2Host-Host Protocol Rules
The workshop addressed several Host-Host protocol issues. The GVB-RET mechanism would be retained despite limited use. The ECO-ERP commands were deemed useful but only one ECO could be outstanding at a time. RST-RRP commands were useful for status checking, but spontaneous RRP commands were forbidden. The workshop established that ERR commands should be logged and verified with the sending site rather than discarded.
For unmatched CLS commands, the group discussed four approaches ranging from holding forever to sequential socket numbering. The workshop also suggested exploring flow control on the control link.
They set rules about how computers ask each other for status and what to do if messages do not match up.
§3Initial Connection and Telnet Protocols
For the Initial Connection Protocol (ICP), the workshop confirmed it was generally satisfactory but emphasized that socket numbers sent by the logger must match those in STR and RTS commands. The implications of queueing these commands needed clarification.
The Telnet committee was reactivated to address terminology issues (half duplex vs. full duplex, character vs. line mode), clarify end-of-line conventions, define the Network Virtual Terminal, and improve specifications for Break and Synch. The workshop agreed that servers have the option to treat logout or disconnection independently and that Synch means examining the data stream for break characters.
They clarified how computers start talking to each other and how to type commands reliably across the network.