On 8/22/11, Chuck Church <[email protected]> wrote: >> >> -----Original Message----- >> From: Lee [mailto:[email protected]] >> Sent: Friday, August 19, 2011 11:05 PM >> To: Chuck Church >> Cc: NSP - Cisco >> Subject: Re: [c-nsp] ARP oddness >> >> Unicast flooding? You didn't say if the destination MAC address was >> known on the switch or no.. >> >> Lee >> >> >> I'm starting to think this is unicast flooding now. Noticed this just >> now: > > VLAN0001 is executing the ieee compatible Spanning Tree protocol > Bridge Identifier has priority 24576, sysid 1, address 001d.453d.f300 > Configured hello time 2, max age 20, forward delay 15 > We are the root of the spanning tree > Topology change flag set, detected flag set > Number of topology changes 913 last change occurred 15:02:50 ago > from GigabitEthernet3/38 > Times: hold 1, topology change 35, notification 2 > hello 2, max age 20, forward delay 15 > Timers: hello 0, topology change 22, notification 0, aging 15 > > That 'topology change flag set' never seems to go away, despite the last > change timer getting up into the hours timeframe now. I'm not sure why this > STP doesn't seem to want to iron itself out.
We had something similar happen between a pair of 6500s and lots of IBM blade switches recently. There was a constant stream of topology change traps for vlan 1 (strange since we don't put anything on vlan 1 & stranger still because it was only vlan 1 having topology changes) I didn't bother trying to figure it out once I noticed that people hadn't been trimming vlan 1 off the trunks for all those blade switches. Removed vlan 1 on all the trunks going to the blade switches and no more topology change traps :) > I'm going to have our vendor > move this to RSTP, which is our standard. Still, not sure why it's doing > this, unless a device is constantly sending out TCNs? Where I work, most probably it'd be users turning their PCs off/on & us forgetting to enable portfast on the user switch ports :) In your case, could it be some interaction between RSTP and IEEE STP? Regards, Lee _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
