Link Flapping In a VLAN between two ports!

taimoor.jan · ‎10-26-2011

Dear Team,

I am getting below loggs on my Router.

002642: *Oct 25 06:32:18.171 PST: %MAC_MOVE-SP-4-NOTIF: Host 000b.ab12.eca7 in vlan 120 is flapping between port Gi3/18 and port Po1

002643: *Oct 25 06:32:18.171 PST: %MAC_MOVE-SP-4-NOTIF: Host 000b.ab12.acb0 in vlan 120 is flapping between port Gi3/17 and port Gi3/18

002644: *Oct 25 06:32:48.171 PST: %MAC_MOVE-SP-4-NOTIF: Host 000b.ab12.b73e in vlan 120 is flapping between port Gi3/18 and port Po1

002645: *Oct 25 06:32:48.171 PST: %MAC_MOVE-SP-4-NOTIF: Host 000b.ab12.b1be in vlan 120 is flapping between port Gi3/18 and port Po1

002646: *Oct 25 06:32:48.171 PST: %MAC_MOVE-SP-4-NOTIF: Host 000b.ab12.ad10 in vlan 120 is flapping between port Gi3/17 and port Gi3/18

002647: *Oct 25 06:32:48.171 PST: %MAC_MOVE-SP-4-NOTIF: Host 000b.ab12.ad10 in vlan 120 is flapping between port Gi3/17 and port Gi3/18

002648: *Oct 25 06:32:48.171 PST: %MAC_MOVE-SP-4-NOTIF: Host 000b.ab12.ad10 in vlan 120 is flapping between port Gi3/17 and port Gi3/18

002649: *Oct 25 06:32:48.171 PST: %MAC_MOVE-SP-4-NOTIF: Host 000b.ab12.ad10 in vlan 120 is flapping between port Gi3/17 and port Gi3/18

002650: *Oct 25 06:32:48.171 PST: %MAC_MOVE-SP-4-NOTIF: Host 000b.ab12.ad10 in vlan 120 is flapping between port Gi3/17 and port Gi3/18

002651: *Oct 25 06:32:48.171 PST: %MAC_MOVE-SP-4-NOTIF: Host 000b.ab12.b326 in vlan 120 is flapping between port Gi3/17 and port Gi3/18

002652: *Oct 25 06:32:48.171 PST: %MAC_MOVE-SP-4-NOTIF: Host 000b.ab12.acb0 in vlan 120 is flapping between port Gi3/17 and port Gi3/18

002653: *Oct 25 06:32:48.171 PST: %MAC_MOVE-SP-4-NOTIF: Host 000b.ab11.fed4 in vlan 120 is flapping between port Gi3/17 and port Gi3/18

002654: *Oct 25 06:32:48.171 PST: %MAC_MOVE-SP-4-NOTIF: Host 000b.ab11.fed4 in vlan 120 is flapping between port Gi3/17 and port Gi3/18

002655: *Oct 25 06:32:48.171 PST: %MAC_MOVE-SP-4-NOTIF: Host 000b.ab12.ad10 in vlan 120 is flapping between port Gi3/17 and port Gi3/18

002656: *Oct 25 06:32:48.171 PST: %MAC_MOVE-SP-4-NOTIF: Host 000b.ab12.ad10 in vlan 120 is flapping between port Gi3/17 and port Gi3/18

002657: *Oct 25 06:32:48.171 PST: %MAC_MOVE-SP-4-NOTIF: Host 000b.ab11.fed4 in vlan 120 is flapping between port Gi3/17 and port Gi3/18

002658: *Oct 25 06:32:48.171 PST: %MAC_MOVE-SP-4-NOTIF: Host 000b.ab11.fed4 in vlan 120 is flapping between port Gi3/17 and port Gi3/18

002659: *Oct 25 06:32:48.171 PST: %MAC_MOVE-SP-4-NOTIF: Host 000b.ab11.fed4 in vlan 120 is flapping between port Gi3/17 and port Gi3/18

002660: *Oct 25 06:32:48.171 PST: %MAC_MOVE-SP-4-NOTIF: Host 000b.ab12.ad10 in vlan 120 is flapping between port Gi3/17 and port Gi3/18

002661: *Oct 25 06:32:48.171 PST: %MAC_MOVE-SP-4-NOTIF: Host 000b.ab12.ad10 in vlan 120 is flapping between port Gi3/17 and port Gi3/18

002662: *Oct 25 06:32:48.171 PST: %MAC_MOVE-SP-4-NOTIF: Host 000b.ab12.ad10 in vlan 120 is flapping between port Gi3/17 and port Gi3/18

002663: *Oct 25 06:32:48.171 PST: %MAC_MOVE-SP-4-NOTIF: Host 000b.ab12.ad10 in vlan 120 is flapping between port Gi3/17 and port Gi3/18

002664: *Oct 25 06:32:48.171 PST: %MAC_MOVE-SP-4-NOTIF: Host 000b.ab12.ad10 in vlan 120 is flapping between port Gi3/17 and port Gi3/18

002665: *Oct 25 06:32:48.171 PST: %MAC_MOVE-SP-4-NOTIF: Host 000b.ab12.b196 in vlan 120 is flapping between port Gi3/18 and port Po1

002666: *Oct 25 06:32:48.171 PST: %MAC_MOVE-SP-4-NOTIF: Host 000b.ab12.ad10 in vlan 120 is flapping between port Gi3/17 and port Gi3/18

002667: *Oct 25 06:32:48.171 PST: %MAC_MOVE-SP-4-NOTIF: Host 000b.ab12.ad10 in vlan 120 is flapping between port Gi3/17 and port Gi3/18

002668: *Oct 25 06:33:10.035 PST: %SPANTREE-SP-2-ROOTGUARD_BLOCK: Root guard blocking port GigabitEthernet9/40 on MST0.

002669: *Oct 25 06:33:11.823 PST: %SPANTREE-SP-2-ROOTGUARD_UNBLOCK: Root guard unblocking port GigabitEthernet3/34 on MST0.

002670: *Oct 25 06:33:11.927 PST: %SPANTREE-SP-2-ROOTGUARD_BLOCK: Root guard blocking port GigabitEthernet3/35 on MST0.

002671: *Oct 25 06:33:12.823 PST: %SPANTREE-SP-2-ROOTGUARD_UNBLOCK: Root guard unblocking port GigabitEthernet3/36 on MST0.

002672: *Oct 25 06:33:14.391 PST: %SPANTREE-SP-2-ROOTGUARD_BLOCK: Root guard blocking port GigabitEthernet2/3 on MST0.

002673: *Oct 25 06:33:15.043 PST: %SPANTREE-SP-2-ROOTGUARD_UNBLOCK: Root guard unblocking port GigabitEthernet9/34 on MST0.

002674: *Oct 25 06:33:16.488 PST: %SPANTREE-SP-2-ROOTGUARD_BLOCK: Root guard blocking port GigabitEthernet9/40 on MST0.

002675: *Oct 25 06:33:16.784 PST: %SPANTREE-SP-2-ROOTGUARD_UNBLOCK: Root guard unblocking port GigabitEthernet3/32 on MST0.

002676: *Oct 25 06:33:17.872 PST: %SPANTREE-SP-2-ROOTGUARD_BLOCK: Root guard blocking port GigabitEthernet9/35 on MST0.

002677: *Oct 25 06:33:18.864 PST: %SPANTREE-SP-2-ROOTGUARD_UNBLOCK: Root guard unblocking port GigabitEthernet9/35 on MST0.

002678: *Oct 25 06:33:20.176 PST: %SPANTREE-SP-2-ROOTGUARD_BLOCK: Root guard blocking port GigabitEthernet9/23 on MST0.

Please help me find the root cause

Br,

Taimur

Vaibhava Varma · ‎10-26-2011

Hi Taimur

What is connected to the Ports Po1,Gi3/17 and Gi3/18..What are the member links of Po1.

Regards

Varma

taimoor.jan · ‎10-26-2011

Dear Varma,

A media gateway of NSN is connected on it, having multiple interfaces coming to Router on vlans.

And the member ports in this channel are :

Gi3/45 Gi3/46 Gi9/41 Gi9/42

Vaibhava Varma · ‎10-26-2011

Hi Taimoor

So Po1 is the Inter-Switch Link between the two Site-Routers and Gi3/17 and Gi3/18 connect to the MGW. Are they connecting to the MGW User Ports or to any internal L2 Switch on theMGW,

What it seems to me is that the MGW connects to both the Site-Routers on the User ports and sending the same MAC via both its interfaces which is causing MAC-Instability ...

Is Po1 a Inter-Switch trunk Link and you are running HSRP for the MGW Vlans. Is MGW dual-homed to two different Site-Routers in question for the same VLAN and both its ports are Active at the same time ?

Regards

Varma

taimoor.jan · ‎10-26-2011

-MGW has internal L2 switch

-MGW is dual homed

-HSRP is being used in the valns

Ganesh Hariharan · ‎10-26-2011

Dear Varma,

A media gateway of NSN is connected on it, having multiple interfaces coming to Router on vlans.

And the member ports in this channel are :

Gi3/45 Gi3/46 Gi9/41 Gi9/42

Taimoor,

Check the NLB Teaming configuration on the server, most probabaly Active/Active will flap the mac-address in the switches.try the configuration with Active/Passive for teaming configuration.

Hope to Help !!

Ganeshh Iyer

Vaibhava Varma · ‎10-26-2011

Hi Taimoor

Is the MGW connected to the Site-Routers via the Internal L2 Switch or via some other dedicated non-Switching unit.

As mentioned above and told by Ganesh this issue is related to learning of the same MAC via two active paths at the same time because at the MGW side its sending out the same MAC via two Active Paths whereas it should have been sending it out via one path only in Active:Standby Mode.

Hope this helps you in your traffic requirment.

Regards

Varma