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Level 9

Fail-closed's Condition?

Hi all,

I have a question: In what condition the sensor will fail-closed? I mean, the Sensor fails, the Sensor's Port is not operating normally or the Link is down?

And what action the Sensor will take for fail-closed? It closed all ports, or only port that is failed?

Thanks and Regards!

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2 Replies
Level 13

Re: Fail-closed's Condition?

HI Totti10,

My understanding is that if the ports are configured to fail closed they will fail closed if there is a link failure, or if the sensor fails.

What do you mean by "If the port is not operating is normally"? 

If you have a link failure on a port that is configured to fail closed it should not affect the other ports on the device. (At least that's how it works with fail-open)

If you need a definitive answer I would suggest you contact support and ask them to clarify the fail closed action for any conditions for your specific sensor model and software version.

If possible I would also recommend testing these scenarios so you can confirm the results.


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Level 9

Re: Fail-closed's Condition?


Consider this simple topology:


My question is, in what condition that Sensor will do a fail-closed:

  1. Sensor is failed(sure, it will fail-closed)
  2. The SW1's G0/0 interface is shutdown, so the Link between SW1 and NSP is down
  3. The 1A port on the Sensor got problem and not operate

And what's action that the Sensor take: Will it close all port on Sensor, or just 2 port on a pair interface?


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