Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!AHWAHNEE.STANFORD.EDU!dcrocker
From: dcrocker@AHWAHNEE.STANFORD.EDU (Dave Crocker)
Newsgroups: comp.protocols.tcp-ip
Subject: Re:  TELNET Buffering Woes
Message-ID: <8905050449.AA02459@ucbvax.Berkeley.EDU>
Date: 4 May 89 17:39:41 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
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It's always nice to do some homework, so I finally did some of mine.

The April 17 draft of the Host Requirements document essentially places
the burden onto the server, since different operating systems need
different details.  The client cannot know which choice is correct.

The HR doc specifies that client Telnet SHOULD have the option of
flushing output, after an IP.  (Personally, I believe the SHOULD should
be a MUST; the impact of not having this feature is enormous.)

Unfortunately, the client is the one that must choose what sequence to
send, so the HR recommends that the sequence be user-configurable.

The Choices listed are:

1.  Urgent(IP, AO, DM); that is, Interrupt Process, Abort OUtput, and
Synchronize the output, via the Data Mark;

2.  Urgent (IP, DM), DO TM; the Abort Output is not sent from the server
telnet to its own operating system, but the Data Mark does a degree of
buffer flushing and the Timing Mark request synchronizes.

3.  Both

Seems to me that this is too important an area to leave this fuzzy.  The
pain of having output continue is significant and greatly reduces Telnet's
credibility.  On the other hand, I don't have any suggestion for how
to improve the spec.

Dave