Re: [foxboro] network storm

  • From: cleddon@xxxxxxx
  • To: foxboro@xxxxxxxxxxxxx
  • Date: Mon, 09 Feb 2009 07:44:32 -0500

I guess I am a little confused, isn't a VLAN the same as a separate switch?? I 
thought the function of the VLAN was to increase the number of broadcast 
domains and thus reduce the broadcast load (both pure and multicast) on the 
devices separated by the VLAN, which in the event of a broadcast storm, what 
ever was in the VLAN would never see that specific broadcast traffic.? That 
said, I am not sure why the SMDH can see FCM's on a VLAN if it can't see them 
on isolated switches.? Also, I don't know, and I am not sure if there is enough 
information is available to tell us if there are important system wide 
broadcasts that all devices need to be aware of (are we over isolating 
ourselves).? The Foxdoc's are pretty definitive about where the IA system must 
be located in a VLAN solution and I don't remember seeing docs 
allowing?segmentation at the VLAN level.?? 
I guess I need to find out what all is in these FCM VLANs and how can it see or 
be seen by the ZCP that references its I/O.? I am also assuming?the ZCP needs 
to be visible by the rest of the system at all times which would not allow it 
to be on a VLAN.? 

I think we need some quality time with the father of the Mesh (Kevin Burak) to 
enlighten all of us peasants to the wonders of the Mesh.


Chuck Leddon
Office Email X2CDLEDD@xxxxxxxxxxxxxx
(770)-497-8247 Home
(404)506-6051 Office
(404)535-0147 Cell
LINC ID: 15*1843


-----Original Message-----
From: Hicks, Gaylon F <gfhicks@xxxxxxx>
To: foxboro@xxxxxxxxxxxxx
Sent: Mon, 9 Feb 2009 1:02 am
Subject: Re: [foxboro] network storm



Let me muddy the water a little (more).  VLANs are supported by Foxboro,
and are part of the MESH configurator tool, and a separate network using
separate switch hardware for the ZCP fieldbus is an officially supported
architecture.  

What is not an explicitly approved architecture is using VLANs to
segment the ZCP field bus(es) from the control network, although
functionally it is the same as the separate switch architecture.  And by
"explicitely approved" I mean it isn't a documented and tested
configuration by Foxboro, although it is pretty obvious that it will,
and does, work fine.  The problem with the separate switches on the ZCP
fieldbus is that you can't monitor those switches and ports in SMDH,
where the VLAN solution does let you monitor those ports. 

The same goes for the multicast rate limiting policies.  Although it
works fine, it doesn't (or didn't) fall under the umbrella of officially
tested configurations.

Russ? - Would you or any of the other Foxboro folks care to weigh in on
this?  If I have mis-stated any of this, please do.

For more light reading on the subject, you can take a look at these
documents - 

B0700AX-H - The MESH Control Network System Planning and Sizing 
B0700AZ-K - The MESH Control Network Architecture Guide
B0700CA-H - The MESH Control Network Operation, and Switch Installation
and Configuration Guide

Thanks,
Gaylon Hicks
TVA - Browns Ferry


-----Original Message-----
From: foxboro-bounce@xxxxxxxxxxxxx [mailto:foxboro-bounce@xxxxxxxxxxxxx]
On Behalf Of Jeremy Milum
Sent: Saturday, February 07, 2009 4:03 PM
To: foxboro@xxxxxxxxxxxxx
Subject: Re: [foxboro] network storm

On Sat, Feb 7, 2009 at 12:01 PM, Boulay, Russ
<russ.boulay@xxxxxxxxxxxxxxxx> wrote:
> ** I'll have to give kudo's to Gaylon, as we reviewed his Mesh Network
a few weeks back.
> It was the cleanest running Mesh system that I have reviewed in the
last few years.
> Vlans for fieldbus, some broadcast limiting, Mesh was running at peak
performance.

many of the suggestions that Gaylan mentions are not supporte
d by
foxboro, yet he has the best
network? that's a bit troubling.

do you perhaps have some recommendations you could give us for setting
up our mesh networks?
 
 
 
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