[LAD] Strange network problem ?

[Fons Adriaensen]

Hello all,

Today I had a strange problem when using the
WFS system here.

The 'master' PC sends a multicast message every
1024 samples (21.333 ms) to all 'render' PCs.
This has to arrive on time, and when it's late
the renderers will mute their output and report
the error in their status messages. 

Today I used some ssh -X logins from my laptop
in the WFS room to the WFS master to run Ardour
and some other apps for a demo. All this worked
well all the time, as it has done before.

I left everything running when going for lunch
with our visitors, and when I returned restarted
Ardour to listen again. I got a lots 'of 'message
too late' errors from the rendering machines, and
interrupted sound. Strange enough this seemed to
be related to the _volume_ of the sounds...

In other words to Ardour's level meters. 
Restarting Ardour in a new ssh login did not
help, but running it directly on the WFS master
solved the problem. So apparently the network
traffic required to update Ardour's meters was
causing the delays. And clearly the whole remote
X session was slower than normal. CPU loads 
looked normal.

Now all this should be peanuts for a Gbit
network that has no other traffic at all,
and it worked perfectly before. I just never
left it running for such a long time.

Anyone an idea as to what is happening here,
and how it could be cured ?

TIA,

-- 
FA

Laboratorio di Acustica ed Elettroacustica
Parma, Italia

Be quiet, Master Land; and you, Professor,
will you be so good as to listen to me ?