From: adz (ccie1day@totalise.co.uk)
Date: Sat Apr 12 2003 - 03:17:57 GMT-3
Hi Mike,
no it shouldn't make a difference, but I beleive certains CATOS's don't like
it..
I was at a client recently who had a large switched network. They were using
the same HSRP group numbers on different VLANS, - so the same HSRP mac
address appeared on two(or more) VLANS.
They had strange connectivity problems, where some machines could talk,
others not.
I worked out what was going on by looking at the CAM tables (6500) and
noting that the HSRP-MAC address disappeared at certain switches.
I never had the opportunity to find out exactly what switch/image was
causing the problem, because fixing the problem was more important - change
the HSRP group number/mac address and the problem went away.
I suspect you may have a similar problem and if you do, what's the CATOS
image?
cheers
Adz
-----Original Message-----
rom: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Mike Williams
Sent: 12 April 2003 05:17
To: CCIELab@Groupstudy.com
Subject: Same MAC on different VLANs?
I know this sounds silly, but does it mess up the switching process when
a switch learns the same MAC on two different VLANs? I have an
incredibly long and detailed story behind my asking this question, but I
won't bore everyone.
I mean, do switches keep separate CAM tables per VLAN? Or is there one
large shared CAM table? Where can I find more info on precisely how
these switches create and operate the CAM tables and the switching
process? (In particular the 4000/4500 and 6500 switches, both with IOS,
no CatOS)
TIA
Mike W.
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