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New Member

Etherchannel and BPDU Filter

Hello Everybody,

Hoping someone can help me with this, if bpdu filter is applied on both ends of an ether channel trunk connecting stacked switches between two locations will stp still see the etherchannel as a single link ? will it result in loops ? the reason for such a scenario is that a few vlans needs to be extended between 2 sites and both these sites have the same sort of stp domain ie, vlans 1-4096 exists on site A and also on site B with core switches on respective sites configured as roots for the vlans. These sites are supposed to be independent but due to some business issues need to extend a few vlans across.






  • LAN Switching and Routing

STP will always see the

STP will always see the EtherChannel as a single logical link regardless of the BPDU filter settings. As long as you can be sure there aren't any L2 connections between these two sites that are outside of the EtherChannel, filtering the BPDUs to keep the locations' STP instances separate won't hurt.

Hi, I'd be careful here.Do I



I'd be careful here.

Do I understand correctly you are using some provider L2 environment to connect your sites?

If yes, you might not be building an Etherchannel between your switches, but between your switch and the provider switch on each site in that case.

Which Etherchannel mode is configured on your switches?


Disabling STP by BPDU filter could cause L2 loops in some cases, I'm afraid.


Best regards,



New Member

Issue resolved by using "on"

Issue resolved by using "on" instead of seems lacp has some issues in this scenario...irrespective of whatever configs i be tried one of the links was not playing ball and ended up as an isolated link causing the loops...changed the mode from lacp to just "on" and it was all stable and both links formed the channel.

The sites are connected via a service provider mux.



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