Re: [foxboro] network storm

  • From: "Doucet, Terrence" <tdoucet@xxxxxxxxxxxxxxxxxx>
  • To: <foxboro@xxxxxxxxxxxxx>
  • Date: Thu, 5 Feb 2009 16:58:15 -0500

Mike,

Cycling power gets you out of trouble relatively quickly but you still do not 
know what caused the trouble. Was there any work going on with any of the 
switches or devices connected to the MESH? Gaylon mentions the Loop Detection 
Policy. If this is not enabled you can easily trigger a storm by interposing a 
HUB between a station on your MESH and then "accidentally" connecting a second 
port on your HUB back to the MESH. But this would kill you right away, so 
unless someone was playing with cables, that is not the cause.

Was anyone testing a new program on an AW? If they were performing a whole lot 
of omget's (or the AIMAPI equivalent) without pausing, that might get you a 
storm.

Terry Doucet, Eng.



-----Message d'origine-----
De : foxboro-bounce@xxxxxxxxxxxxx [mailto:foxboro-bounce@xxxxxxxxxxxxx] De la 
part de Hicks, Gaylon F
Envoyé : February 5, 2009 4:00 PM
À : foxboro@xxxxxxxxxxxxx
Objet : Re: [foxboro] network storm

Hi Mike,

I am Chicken Little no more!  This happens to be one of my favorite pet
peeves and soapbox issues with the Foxboro mesh network.  Boring
discussion below.

There are things you can do in the switches to reduce your vulnerability
to these network storms.  One is to configure all your broadcast packet
limits on all 100MB ports to 500 packets/second, and if your switches
will support it, implement the Loop Detection Policy (LDP) algorithm.
There is also a multicast packet suppression policy you can implement,
but Foxboro does not officially support that.  And (my personal
favorite) you can implement VLANs to segment your ZCP field bus from
your ZCP Control Network.  Also not officially support, but useful.

One thing we have seen with the ZCPs while doing network storm testing
is that the ZCP/FCM communications start to get sloooooow, and I/O
updates slow down.  Depending on your process, this can be a problem.
We'll probably discuss this issue at the SEUG meeting next week.  Are
you going to make it?  Either way, feel free to give me a call or email
if you want to talk about this in more detail.  

Good luck with everything.

Thanks,
Gaylon Hicks
TVA - Browns Ferry


-----Original Message-----
From: foxboro-bounce@xxxxxxxxxxxxx [mailto:foxboro-bounce@xxxxxxxxxxxxx]
On Behalf Of Michael Jaudon
Sent: Thursday, February 05, 2009 1:27 PM
To: foxboro@xxxxxxxxxxxxx
Subject: [foxboro] network storm

We experienced a first for our plant site today.  We had all
workstations,
on the mesh side of the network, to "smurf" out.  Upon visually checking
our
ZCP270s I noticed that of each of the ZCP270s had gone single with it's
associated FT module gone to red/green.
Looking at the switches...we have 3 sets of switches including the root
switch.  On each of the switches the lights were all flashing rapidly
and in
unison.  It wasn't until we cycled the power on the root switches (one
at a
time) that the network came back.

Talking to our field service rep...he said the situation we had was a
"network storm".  The cause is unknown.

My question is has anyone ever experienced a "network storm" on a mesh
network and if so what caused it?

Our mesh network has been in operation since Oct 2008 and this is the
first
issue we have had with it.

We are running a Mesh Network version 8.4.1.

-- 
Mike Jaudon
Tronox, LLC
Hamilton, MS


 
 
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_______________________________________________________________________
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Systems (formerly The Foxboro Company). Use the info you obtain here at
your own risks. Read http://www.thecassandraproject.org/disclaimer.html
 
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to subscribe:         mailto:foxboro-request@xxxxxxxxxxxxx?subject=join
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