Re: [PATCH] Using TCP_NODELAY unconditionally

[Nicolas Williams <Nicolas.Williams%ubsw.com@localhost>]

On Tue, Jan 22, 2002 at 12:23:53PM -0500, Bill Sommerfeld wrote:
> [wg chair hat off]
> 
> > It's not clear yet that forwarding X11 traffic with SSHv2 and Nagle
> > turned on is a problem. 
> 
> In my experience, it is; most ssh implementations turn off nagle on
> "interactive" connections.

OpenSSH doesn't. Which implementations do?

> > But this issue may yet come up again. So it's probably worth
> > addressing, even if just to state that Nagle is to remain on at all
> > times...
> 
> Applications which attempt to track mouse movement (e.g., scroll bar
> sliders) don't work very well with nagle turned on.  my understanding
> is that "animated" widgest typically require 24-30 updates per second
> before it begins to look smooth, while the interaction between delayed
> acks and nagle cause very bursty behavior.

Yes, this is my understanding as well. I'll do a simple test of X11
forwarding with OpenSSH with and without Nagle and with some intensive
application - nothing scientific, mind you, just a simple test to get a
feel of how much of a difference turning off Nagle makes with X11.

Rick Jones makes the argument, on the OpenSSH list, that forwarding of
other protocols should be done with Nagle turned off, that the
forwarded traffic's characteristics would thus mirror the
characteristics of the original traffic. I agree. I just don't know
whether it would be problematic to run interactive character-based
sessions without Nagle.

If SSH runs best with Nagle turned off then the draft RFCs should state
it, possibly  with "SHOULD" language.


> 					- Bill


Cheers,

Nico
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