Hello!
Please, take a look at the attached scheme.
Client has a VLAN link through the provider network.
Connection points (to SW-1 and SW-4) are geographically distributed (about 400 km).
All provider switches are L3, interfaces Gi0/1 and Gi0/2 on SW-1 and SW-4 are as configured L2 access switchports.
Here are some stats for border switches:
SW-1#show mac-address-table interface GigabitEthernet 0/1
Mac Address Table
-------------------------------------------
Vlan Mac Address Type Ports
---- ----------- -------- -----
4 001b.2bxx.xxxx DYNAMIC Gi0/1
4 001c.f6yy.yyyy DYNAMIC Gi0/1
Total Mac Addresses for this criterion: 2
SW-4#sh mac-address-table interface gigabitEthernet 0/2
Mac Address Table
-------------------------------------------
Vlan Mac Address Type Ports
---- ----------- -------- -----
4 0000.cd1f.ad2f DYNAMIC Gi0/2
4 0000.cd33.85b5 DYNAMIC Gi0/2
<............cut...........>
4 485b.3914.dde5 DYNAMIC Gi0/2
Total Mac Addresses for this criterion: 179
On all switches (SW-2, SW-3,SW-4) except SW-1 logs are full of flap warnings:
SW-4#sh logging
<............cut...........>
Jul 2 02:39:22.165 MSD: %SW_MATM-4-MACFLAP_NOTIF: Host 001c.f6yy.yyyy in vlan 4 is flapping between port Gi0/2 and port Gi0/24
Jul 2 02:39:32.978 MSD: %SW_MATM-4-MACFLAP_NOTIF: Host 001c.f6yy.yyyy in vlan 4 is flapping between port Gi0/2 and port Gi0/24
Jul 2 02:39:59.366 MSD: %SW_MATM-4-MACFLAP_NOTIF: Host 001c.f6yy.yyyy in vlan 4 is flapping between port Gi0/2 and port Gi0/24
What could cause such appearance of one MAC (001c.f6yy.yyyy) on the Gi0/2 interface of SW-4 ?
What are the ways to:
1)block the appearance of that MAC on SW-4 Gi0/2 ?
2)supress appearance of MATM warnings in log ?
Client says that there could happen some looping on his backbone.
I also learned from previous discussiona, that a close to my case - there could be some concerns with PIX/ACA failover configuration.
Thanks.
Alex.
DAO21-RIPE
