[X2Go-Dev] Traffic shaping nightmare - missing SSH TOS bits

[John A. Sullivan III]

On Tue, 2012-02-21 at 10:11 +0100, Jan Engelhardt wrote:
> On Tuesday 2012-02-21 09:43, John A. Sullivan III wrote:
> 
> >On Tue, 2012-02-21 at 09:30 +0100, Jan Engelhardt wrote:
> >> On Tuesday 2012-02-21 07:05, John A. Sullivan III wrote:
> >> 
> >> >I've been working on a project to implement traffic shaping
> >> >to conform to 95th percentile billing including our X2Go virtual
> >> >desktops. One of the challenges is prioritizing the interactive X2Go
> >> >traffic (screen, keyboard, mouse) differently from bulk traffic like
> >> >local share transfers, printing, and possibly sound.  I thought this
> >> >would be trivial because of the SSH transport since SSH sets the
> >> >minimize-delay bit for interactive traffic and the maximize-throughput
> >> >bit for bulk transfers.
> >> 
> >> If a user has his own machine, he can of course do whatever he wants.
> >> Second, if he can pass options to ssh, he can set the QOS type
> >> arbitrarily, and even where that is not available for control, one
> >> can still cause the openssh client to use interactive TOS marking for
> >> bulk transfers, since secondary ssh channels (e.g. tunnels) do not
> >> pass up the TOS mark.
> ><snip>
> >However, Windows and Mac clients may not be using OpenSSH.
> 
> That too. All these reasons is why TOS is not a reliable characteristic 
> to determine the question of bulk-or-interactive.
Thanks.  I suppose we are saying the same thing in a different way.  I
am saying we cannot rely upon libssh setting a TOS bit but we do need to
do something within X2Go to allow admins to distinguish the traffic.  We
need some method embedded in the traffic.  The obvious choice is to use
either TOS bits or DSCP but we do need to set something - John
> 
> >PS - out of curiosity, now does one set the QoS type in OpenSSH?
> 
> ssh -o IPQoS={bulk|interactive|0x12345} ...
> 
> ssh -L 2000:localhost:22 foohost &
> rsync -HPave 'ssh -p 2000' bulky.iso localhost:
> 
> and in fact, wouldn't the output `ls -Rl /` in an interactive shell also 
> best be count as bulk...
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