[mrtg] Re: Any ethernet switch which always floods?

Steve Rowe steve.rowe at sheridanc.on.ca
Thu Oct 18 17:53:25 MEST 2001


We're currently using a 3500XL switch for this purpose.  There are nine 
active data connections to the switch and we are port monitoring on three 
additional ports.  We average 150GB per day traffic through this switch 
(uni- and multi-cast) with the CPU averaging 48% usage, only varying 2-3% 
either way, and haven't had any issues.


At 10/18/01 - 08:27 AM, you wrote:

>Right now we're in a test situation without all the taps in place that we
>ultimately want to use, so CPU is pretty low. I can't see the real-world
>effect of SPANing (or not) to multiple ports with lots of data pouring into
>the switch. Cisco TAC has told me that SPAN eats up cycles, and at some
>point I could lose packets because the switch would be overwhelmed. I'm
>trying to make the setup as economical as possible to minimize the chance of
>that happening, but it's possible what we actually need won't tax the box
>beyond its capabilities.
>-----Original Message-----
>From: Paul C. Williamson [mailto:pwilliamson at mandtbank.com]
>Do you know what the CPU is doing?  You could monitor
>the effect of the Span on the cpu if you can get a good
>baseline without it...
> >>> SHOLAAS Margaret G <Margaret.G.SHOLAAS at ris.lane.or.us> 10/16/01 11:04PM
> >>>
>I am using a Cisco switch. I'm trying to avoid mirroring (SPAN), since it's
>more CPU intensive than flooding, but I may not be able to. Thanks for the
>suggestion, though.
>Unsubscribe mailto:mrtg-request at list.ee.ethz.ch?subject=unsubscribe
>Archive     http://www.ee.ethz.ch/~slist/mrtg
>FAQ         http://faq.mrtg.org    Homepage     http://www.mrtg.org
>WebAdmin    http://www.ee.ethz.ch/~slist/lsg2.cgi

/ __|______| _ \___________________________________________________________
\__ \      |   /                       Network Analyst - Data Systems Group
____/TEVE  |_|_\OWE               Information Technology - Sheridan College
                                     Trafalgar Campus - Oakville, ON, Canada
steve.rowe at sheridanc.on.ca                                         ./\.
Phone: 905-845-9430 x2032       ICQ:                            _|\|  |/|_
http://numb.sheridanc.on.ca   14509731                          \        /
Make something idiot proof and someone will make a better idiot.    /

Unsubscribe mailto:mrtg-request at list.ee.ethz.ch?subject=unsubscribe
Archive     http://www.ee.ethz.ch/~slist/mrtg
FAQ         http://faq.mrtg.org    Homepage     http://www.mrtg.org
WebAdmin    http://www.ee.ethz.ch/~slist/lsg2.cgi

More information about the mrtg mailing list