Experimental Physics and
Industrial Control System

"Garrett D. Rinehart" <[email protected]> · Thu, 9 Dec 1999 15:06:47 -0600 (CST)

Grasping at straws, I started killing MEDM displays on the control workstations. One of them 
was an XY plot of beam profiles (~75 channels total @ 30Hz rate). Turning that 
display on and off had almost the same effect on the stalling problem (turned 
on, big problem; turned off, almost no problem).

About that time, as I was preparing to answer difinitively, "the network is 
overloaded", the network sniffer was made available. Hooking it up, we found no 
errors, an incredibly small number of collisions (about 0.001%), and only 10% 
network utilization (peak).

Meanwhile, my little box with the LEDs that adapts between the "thin" section of 
the network and the 10/100baseT hub is still showing collisions galore.

Oh, BTW, Marty or Jeff asked earlier if it was a switched network. Yes, it is. I 
have three workstations, a printer, and a couple of PCs running off a 
10/100baseT hub. Then there's all the iocs remaining on the old thinwire which 
is attached through an adapter box to hub.

So, now the questions are:
1) Has the sniffer been sniffing something funny and lost it's mind?
2) Are the indications on the adapter box misleading?
3) Are the collisions between the thinwire and UTP parts of the net and the 
sniffer can't see 'em?
4) Why has it just suddenly become so much worse?
5) Won't somebody send me an aspirin?

Thanks everybody for your help.

Garrett Rinehart
Intense Pulsed Neutron Source
Argonne National Laboratory
9700 S. Cass Ave
Argonne, IL  60439
(630)252-6561

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System