QnQ Looping

[lmanavalan]

Hi,

I have configured 2 QnQ in parallel as shown in the attachment diagram. But some reason its causing a loop in spite i have the spanning-tree configured with high cost.

can i configure 2 interface connected to the same switch with same vlan 3505 or do i have to use different vlans say vlan 3505 and 3506

Below is the logs

Apr 24 00:01:06.284 UTC: %PM-SP-4-ERR_DISABLE: l2ptguard error detected on Gi1/1, putting Gi1/1 in err-disable state
Apr 24 00:01:06.456 UTC: %PM-SPSTBY-4-ERR_DISABLE: l2ptguard error detected on Gi1/1, putting Gi1/1 in err-disable state
Apr 24 00:01:07.456 UTC: %SYS-SPSTBY-3-LOGGER_FLUSHED: System was paused for 3y30w to ensure console debugging output.
Apr 24 00:02:11.529 UTC: %QNQ-6-NATIVE_VLAN_TAGGING: Please enable the native VLAN tagging feature for proper functioning of the Q-in-Q service.

regards

Logesh

[Philip D'Ath]

Which device generated the %QNQ-6-NATIVE_VLAN_TAGGING error?

Why not form a LACP Etherchannel instead and make it loop free?

[lmanavalan]

Hi

the ISP Switch A is spitting the error. I can configure the port at the ISP Switch A but, on the other end 2 different switch is connected to Customer switch 2.

Thanks

Logesh

[lmanavalan]

Adding more info

aftet bring up the second link the customer service got affected and also lost access to the ISP Switch 2 and 3 

thanks

logesh

[lmanavalan]

Hi

To resolve the issue instead of using the same vlan 3505 on Switch A i used vlan 3505 on interface gi1/1 and vlan gi 2/1 on interface 2/1. Everything was working fine for a while.

But the issue came back again. This time i found that the dot1q tunnel is automatically adding the command "spanning-tree BPDU filter enable" on the interface.

i expecenced the same errors in the log

%PM-SP-4-ERR_DISABLE: l2ptguard error detected on Gi1/1, putting Gi1/1 in err-disable state
%PM-SP-4-ERR_DISABLE: l2ptguard error detected on Gi2/1, putting Gi2/1 in err-disable state
%PM-SPSTBY-4-ERR_DISABLE: l2ptguard error detected on Gi1/1, putting Gi1/1 in err-disable state
%PM-SPSTBY-4-ERR_DISABLE: l2ptguard error detected on Gi2/1, putting Gi2/1 in err-disable state

its been mentioned to add the vlan tag native vlan. How this could help resolve the issue.

Regards

Logesh