[c-nsp] Mac address flapping..

[Mateusz Blaszczyk]

Alan,

But why only 1 MAC is flapping?

HSRP sends dest-mac as multicast address so there are clearly 2 paths
between these switches.
Unless the connection is unidrecional somehow, how on earth he doesn't
see same on second 6509-b?

It's confusing.

-mat

2009/7/13  <A.L.M.Buxey at lboro.ac.uk>:
> hi,
>
>
> i originally thought on the same lines too - but then having
> been told this still happens if theres only one link
> to the 4500s to the client - which makes the 6506-b almost
> a router at the end of a stick for that network things started
> to look a little 'wonky'.  it wouldnt be taking traffic from
> another port(?).
>
> as far as i now see, you have 2 routers, A and B.   A has the feed to
> the switch (and the only physical link to the customer) whilst
> B is connected to A via a portchannel and trunk link. a MAC for
> vlan042 is still flipping between the down-link from A and the
> link from A to B.  now, from my deepest memories I've seen this sort
> of thing happen on our campus in the past... i've got some feeling that
> somewhere, that VLAN is being fed into your network as another VLAN
> and therefore the AMC is squirting back out and through - eg native vlan 042
> is patched to vlan 1 or somesuch elsewhere, therefore the MAC is seen
> coming back t;other way
>
> alan
> _______________________________________________
> cisco-nsp mailing list  cisco-nsp at puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-nsp
> archive at http://puck.nether.net/pipermail/cisco-nsp/
>