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I'm currently looking at physical interface damping on Juniper MX.

Fun Fact: Nowhere on this site is it mentioned that the penalty added per interface down event is 1000.

Currently testing this:

set interfaces xe-5/2/1 damping half-life 30
set interfaces xe-5/2/1 damping max-suppress 20000
set interfaces xe-5/2/1 damping reuse 1
set interfaces xe-5/2/1 damping suppress 500
set interfaces xe-5/2/1 damping enable

This seems to be working but I'm basically missing two things:

  1. Where can I see the current penalty on the interface? "show interface extensive" only lists the configured parameters and the state (suppressed/unsuppressed) of the interface:

    Damping : half-life: 30 sec, max-suppress: 20000 sec, reuse: 1, suppress: 500, state: suppressed

  2. Is there a way to manually clear the interface / reset the penalty so that it comes up immediately again?

  • If your use case is one where you want the interface to stay down after X number of flaps within Y time period, an event script may work for you. I have one that I can update in my answer if you're interested. That on its own or combined with hold times may achieve what you're after. – Jordan Head Jan 21 at 15:25
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Where can I see the current penalty on the interface?

There isn't a show command for this.

If you are looking at this from a testing perspective, you can jump on the FPC shell start shell pfe network fpcX and issue the debug interface flaps command to see penalty specifics (disable with undebug interface flaps)

[Jan 21 02:02:25.667 LOG: Debug] IFD: xe-5/1/10, penalty: curr = 861.554267, new = 1861.554267, max = 16000, ttr=26895ms, elapse time = 6450

Is there a way to manually clear the interface / reset the penalty so that it comes up immediately again?

Nothing purpose built for this case, no. I'd speculate that administratively downing the interface might do this, but I'm not sure if it resets the clock or not. And, to be honest, probably is not the ideal scenario.

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