Hi, I've had a problem on a pair of 4500 switches with a MAC address. We first noticed the CPU being at 99%, and upon investigating, noticed one switch complained about a flapping MAC address. Further examination showed that the two switches showed the MAC being advertised from the other's TenGB interface - they're running with dual TenG in a REP loop. Now while there are lots of VLANs and devices connected to the two switches, it only happened with one single MAC on one VLAN. Examining the REP structure resulted in this output:
switch1#show rep topology REP Segment 1 BridgeName PortName Edge Role ---------------- ---------- ---- ---- switch1.fd3 Te4/1 Pri Alt switch2.fd3 Te4/1 Open switch2.fd3 Te3/1 Open switch1.fd3 Te3/1 Sec Open (same for both) DIsplaying the detailed version showed this: REP Segment 1 switch1.fd3, Te4/1 (Primary Edge) Alternate Port, some vlans blocked Bridge MAC: 0023.5ef0.d2c0 Port Number: 0100 Port Priority: 050 Neighbor Number: 1 / [-4] [..] switch1.fd3, Te3/1 (Secondary Edge) Open Port, all vlans forwarding Bridge MAC: 0023.5ef0.d2c0 Port Number: 0C0 Port Priority: 010 Neighbor Number: 4 / [-1] (same for both switches) Switch1 is the one that has the MAC that was flapping, between a portchannel that is physically connected to the device sourcing that mac, and the Ten3/1 interface. The second switch showed the MAC being sourced on Ten4/1. I temporarily "fixed" this flapping as well as the high CPU load by blocking the VLAN in question on one of the TenG interfaces ... Here's the port configs: interface TenGigabitEthernet3/1 switchport trunk encapsulation dot1q switchport mode trunk rep segment 1 edge preferred rep preempt delay 15 interface TenGigabitEthernet4/1 switchport trunk encapsulation dot1q switchport trunk allowed vlan 1-212,214-4094 <- did this to mitigate the loop problem switchport mode trunk rep segment 1 edge preferred rep preempt delay 15 Switch2: interface TenGigabitEthernet3/1 switchport trunk encapsulation dot1q switchport mode trunk rep segment 1 rep preempt delay 15 interface TenGigabitEthernet4/1 switchport trunk encapsulation dot1q switchport mode trunk rep segment 1 rep preempt delay 15 Any idea what's going wrong here? This only started when we added a port with access to VLAN 213 on switch2 ... Tnx, -gg _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
