Strange behavior with interface in mode L2 or Vwire with the function preempt

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Strange behavior with interface in mode L2 or Vwire with the function preempt

Not applicable

I contact the KB because I need to have some explanations or best practice for a specific configuration.My issue is I observed in a specific configuration (interface in mode L2 or Vwire with the function preempt active and link monitoring) a strange behavior of the HA.When you shut down an interface from the active member, you have some flaps (defect device becomes master and the production is degraded on this device: the interface is always down).

Did you observe it?

Also I think the function preempt is not possible with interfaces in mode L2 or Vwire.Can you confirm it with your experience?

Furthermore what is the best practice when you want to integrate a device with some interfaces in mode L3 and some interfaces in mode L2 or Vwire?
I already opened a case at the support but I will get advantage of the KB.

Thanks for your help.




Not applicable


I had same problem you had and I make all the interfaces to L3 and problem solved. please plan carefull before you raise interface to L3.




Thanks for he reply.

I tested in L3 and no problem. But I must to stay in L2 or Vwire and also the preempt is not possible with this mode when you use link monitoring. I don't find the information in documentations or KB.

Anybody have an idea or precision ?



L4 Transporter


Can you please restate your question with more details. I am not exactly sure what you are trying to do.


Hi Phil,

I realized some tests in mode L2 / L3 or L2+L3 with the function 'preempt' active.

My conclusion is the mode preempt is not possible in Mode L2 with the link monitoring.

My goal was to combine a device with interface L3 and L2 in the mode preempt.

When you test it, you can observe a flip flap of the devices and degradation of service (during a time that you configured with the option Maximum No. of Flaps and the hold time). When you shut down an interface, the defect device becomes master with an interface down during 1 mn. Also you have an interruption of service.

Do you test it in this mode ?



I cant speak for our QA dept, I gather from your response that you are asking if we test in a multi mode setup. I am not aware of the particular methodology used in testing for failover but I can say that Vwire and L3 hybrid firewall's are not all that unique. For that reason alone I would expect extensive testing in this type of configuration.


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