[c-nsp] Layer-2 Flapping log messages

[Djerk Geurts]

Afaik, it's a message about a MAC address in the CAM table shifting to
another port before it has timed out and removed from the CAM table.

3 options possible:

- Duplicate MAC address on the network
- L2 loop (great for broadcast storms)
 Loop could exist due to:
 - STP error (configuration etc)
 - Switch attched with 2 ports (also an STP error)
- Someone with a laptop moving his laptop from one desk to another

Djerk

> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net 
> [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Robert Walton
> Sent: Wednesday, January 12, 2005 9:55 AM
> To: cisco-nsp at puck.nether.net
> Subject: [c-nsp] Layer-2 Flapping log messages
> 
> 
> Hi,
> 
> 	Just looking at some logs for flapping and wonder what 
> the difference is between these two logs i.e. is there a 
> specific meaning behind the specifying of the interfaces 
> being the opposite way round on the second log entry.
> 
> Jan 10 12:07:35.776 GMT: %C4K_EBM-4-HOSTFLAPPING: Host 
> 00:00:5E:00:01:1C in vlan 215 is flapping between port Fa2/48 
> and port Fa2/3
> Jan 10 12:07:41.676 GMT: %C4K_EBM-4-HOSTFLAPPING: Host 
> 00:00:5E:00:01:1C in vlan 215 is flapping between port Fa2/3 
> and port Fa2/48
> 
> cheers,
> Rob
> 
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