From: Tim (ccie2be@nyc.rr.com)
Date: Fri Sep 16 2005 - 08:03:12 GMT-3
Leigh,
I had looked into these same issues myself fairly recently. I came to the
conclusion that the parameters, operations and default values are exactly
the same as with BGP dampening.
To me, it seems that all cisco did was take the bgp dampening code and make
it so that it can be applied to an interface.
So, if you know bgp dampening, you already know event dampening.
HTH, Tim
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Leigh Harrison
Sent: Friday, September 16, 2005 6:34 AM
To: Cisco certification
Subject: IP Event Dampening
All,
I've had a good read through Cisco's document on IP Event Dampening.
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122s/122snwft/re
lease/122s14/fsipevdp.htm
However, I think it's getting to that time were I need to take a break.
I can't for the life of me see what the default penalty value is.
I know that the half-life halves the total accumulated penalty after "x"
seconds
I get that the Suppress Threshold is the value that will cause an
interface to be dampened
Reuse Threshold is value it has to fall below before it is classed as
working again
Max Suppress time is the total time it will stay dampened for - though
I'm not 100% sure why you would need this ?? Surely if a link is
flapping, you wouldn't want the penalty reset after 60 (or so) seconds ?
eg. dampening 15 1000 4000 60
half life of 15 seconds
reuse threshold of 1000 "penalty points"
suppress threshold of 4000 "penalty points"
max suppress of 60 seconds
From this I guess that the max suppress would be used if my interface
flapped 20 times in the first 15 seconds and then stopped flapping,
accumulating a massive penalty, so that I would not have it dampened for
longer than need be.
BUT!! What is the penalty value for a flap?? I've got the figure 1000
in my head - is this right ? Is this set in stone, or is it a
configurable value ?
Any help much appreciated - I need a cup of tea....
LH
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