[c-nsp] %SW_MATM-4-MACFLAP_NOTIF and q-in-q tunnels...

[Rhett Bassett]

Gurus-

  I've got a misbehaving customer with a L2 VLAN tossing all sorts of
%SW_MATM-4-MACFLAP_NOTIF messages - from different (though a limited
set) MACs.  Okay, so they have a loop of some sort - fine.

  To wit:
Feb 13 12:25:31: %SW_MATM-4-MACFLAP_NOTIF: Host 0012.3fXX.XXXX in vlan
YYY is flapping between port Gi0/26 and port Gi0/27
Feb 13 12:25:32: %SW_MATM-4-MACFLAP_NOTIF: Host 000b.dbXX.XXXX in vlan
YYY is flapping between port Gi0/27 and port Gi0/28

  Problem is, this customer's VLAN transits one of our provider's q-in-q
tunnels (along with several other customers), which is causing all sorts
of bad.  On seeing this looping behaviour, our provider is shutting the
entire tunnel down.  This is less than optimal, from our standpoint.

  Outside of asking my customer to clean up whatever is looped, which
has been done, is there anything I can turn on (rate limit / flap
detection / port security / etc) to clamp them before this becomes a
problem?  Setting up MAC access-lists seems wrong...  We're talking a
3550, here.  At the moment, I'm having to manually rip their VLAN off of
the port facing the q-in-q tunnel, which seems like a bigger hammer than
necessary.

  Google results for the error message itself are slim, and everything I
see for "flap" in the configuration guides is aimed toward protocols
(BGP, LACP, etc), and not L2 stuff...

  Thanks in advance.

-- 
Rhett Bassett
Hunter Communications
(541)734.2800 x2117
http://www.coreds.net