From: Victor Cappuccio (cvictor@protokolgroup.com)
Date: Fri Jul 28 2006 - 04:50:25 ART
Hello Pankaj, this is what Petr explained in his email to the GS
It seems that this topic is very attractive, because you have lots of the
same threads in the Archives
Saludos,
Victor.-
====================================================================
Hi,
hm, let's see :)
If we got 1000 for every flap, then for 3 quick flaps in a row,
theoretically, we accumulate 3000. If Suppress value is set to 2000
then after those three flaps we got our interface suppressed. Now
penalty starts to decay exponentially by simple law
CurrentPenalty = StartPenalty*2^(-t/HLife) (it halves every HLife time)
Interface become unsuppressed when CurrentPenalty hits ReuseValue.
Now, half of 3000 is 1500, and thus, by setting Half-Life to 30 secs, and
Reuse Value
to 1500, we could get close to desired result.
dampening 30 1500 2000 100
Why MaxSuppressTime is 100? Well maximum _possible_ PenaltyValue is 20000.
and our
MaxPenalty = ReuseV*2^(MaxST/HLife) - this is the penalty value,
which decays to ReuseValue in MaxSuppressTime.
So setting MaxST to 100, brings MaxPenalty below the possible limit, but
setting it to 120, makes MaxPenalty jump over.
________________________________________
De: pankaj kumar [mailto:pankaj_mcse123@rediffmail.com]
Enviado el: Viernes, 28 de Julio de 2006 01:25 a.m.
Para: Victor Cappuccio
CC: ccielab@groupstudy.com; 'Sami'
Asunto: Re: RE: dampening
Hello Victor,
How did you mark Reuse limit 1500 & suppress limit default &
Maximum suppress limit is 100. I couldnt understand. Could you explain it?
Here you are putting all values for BGP dampening but not interface event
dampening.
Thanks,
Pankaj
On Fri, 28 Jul 2006 Victor Cappuccio wrote :
>Sami,
>
>Some good links
>http://www.groupstudy.com/archives/ccielab/200603/msg00204.html
>
>http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/120newft/12
0
>limit/120s/120s22/s_ipevdp.htm#wp1027177
>
>The answer for your question:
>dampening 30 1500 2000 100
>
>And some outputs from a Router.
>
>To resume the output below
>1st Flap at Jul 27 00:14:58.985 penalty 1000, flap count 1
>2nd Flap at Jul 27 00:15:11.125 penalty 1755, flap count 2, Diff 1st Flap &
>2nd Flap almost 13s
>3er Flap at Jul 27 00:15:23.614 penalty 2331, now suppressed with a reuse
>intervals of 20 12
> from a amount of 25 sec.
>
>R2(config-if)#do show run int s0/0 | in damp
>
> dampening 30 1500 2000 100
>
>R2(config-if)#s
>
>R2(config-if)#
>
>Jul 27 00:14:58.985: IF-EvD(Serial0/0): IP Routing reports state transition
> from UP to DOWN
>===========================================================================
=
>Jul 27 00:14:58.985: EvD(Serial0/0): charge penalty 1000, new accum.
penalty
>1000, flap count 1
>===========================================================================
=
>Jul 27 00:14:58.985: EvD(Serial0/0): accum. penalty 1000, not suppressed
>===========================================================================
=
>Jul 27 00:14:58.985: IF-EvD(Serial0/0): update IP Routing state to DOWN,
>interface is not suppressed
>===========================================================================
=
>
>R2(config-if)#s
>R2(config-if)#
>===========================================================================
=
>Jul 27 00:15:11.125: IF-EvD(Serial0/0): IP Routing reports state transition
> from UP to DOWN
>===========================================================================
=
>Jul 27 00:15:11.125: EvD(Serial0/0): accum. penalty decayed to 757 after 12
>second(s)
>===========================================================================
=
>Jul 27 00:15:11.125: EvD(Serial0/0): charge penalty 1000, new accum.
penalty
>1757, flap count 2
>===========================================================================
=
>Jul 27 00:15:11.125: EvD(Serial0/0): accum. penalty 1757, not suppressed
>
>===========================================================================
=
>R2(config-if)#s
>R2(config-if)#
>===========================================================================
=
>Jul 27 00:15:23.614: IF-EvD(Serial0/0): IP Routing reports state transition
> from UP to DOWN
>===========================================================================
>Jul 27 00:15:23.614: EvD(Serial0/0): accum. penalty decayed to 1331 after
12
>second(s)
>===========================================================================
>Jul 27 00:15:23.614: EvD(Serial0/0): charge penalty 1000, new accum.
penalty
>2331, flap count 3
>===========================================================================
=
>Jul 27 00:15:23.614: EvD(Serial0/0): accum. penalty 2331, now suppressed
>with a reuse intervals of 20, ::::: THE INTERFACE IS SUPPRESSED::::
>===========================================================================
=
>Jul 27 00:15:23.614: IF-EvD(Serial0/0): update IP Routing state to DOWN,
>interface is suppressed
>R2(config-if)#
> Jul 27 00:15:25.613: %LINK-5-CHANGED: Interface Serial0/0, changed state
to
>administratively down
>R2(config-if)#n
>Jul 27 00:15:25.613: IF-EvD(Serial0/0): IP Routing reports state transition
> from DOWN to DOWN
>Jul 27 00:15:26.614: %LINEPROTO-5-UPDOWN: Line protocol on Interface
>Serial0/0,changed state to down
>Jul 27 00:15:26.614: IF-EvD(Serial0/0): IP Routing reports state transition
> from DOWN to DOWN
>R2(config-if)#n
>R2(config-if)#
> Jul 27 00:15:26.815: IF-EvD(Serial0/0): IP Routing reports state
transition
> from DOWN to UP
>R2(config-if)#
> Jul 27 00:15:28.814: %LINK-3-UPDOWN: Interface Serial0/0, changed state
to
>up
>R2(config-if)#
> Jul 27 00:15:28.814: IF-EvD(Serial0/0): IP Routing reports state
transition
> from UP to UP
>Jul 27 00:15:28.814: IF-EvD(Serial0/0): IP Routing reports state transition
> from UP to UP
>Jul 27 00:15:29.816: %LINEPROTO-5-UPDOWN: Line protocol on Interface
>Serial0/0, changed state to up
>Jul 27 00:15:29.816: IF-EvD(Serial0/0): IP Routing reports state transition
> from UP to UP
>
>HTH
>Victor.-
>
>
>
>-----Mensaje original-----
>De: nobody@groupstudy.com [mailto:nobody@groupstudy.com] En nombre de Sami
>Enviado el: Miircoles, 26 de Julio de 2006 06:03 p.m.
>Para: ccielab
>Asunto: dampening
>
>Group,
>
>One of the task say ..3 interfcae flaps in 30 second will keep interface
>participating in routing...Is this correct ?
>
>dampening 30 1000 2000 120..
>
>Thanks
>
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>
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