GroupStudy.com GroupStudy.com - A virtual community of network engineers
 Home  BookStore  StudyNotes  Links  Archives  StudyRooms  HelpWanted  Discounts  Login
RE: Interface Dampening [bcc][faked-from][bayes] posted 07/14/2005
[Chronological Index] [Thread Index] [Top] [Date Prev][Date Next] [Thread Prev][Thread Next]


Dampening for an interface uses a half life value in seconds.  With a range
of 1-30 seconds, the penalty will decay very quickly.

IP Event Dampening
http://www.cisco.com/en/US/products/sw/iosswrel/ps1838/products_feature_guid
e09186a0080134a41.html#wp1048359
 
Marvin Greenlee, CCIE#12237, CCSI# 30483
Network Learning Inc
marvin@xxxxxxxxxxxxxx
www.ccbootcamp.com (Cisco Training)


-----Original Message-----
From: nobody@xxxxxxxxxxxxxx [mailto:nobody@xxxxxxxxxxxxxx] On Behalf Of
ccie2be
Sent: Thursday, July 14, 2005 2:36 PM
To: buesink@xxxxxx; ccielab@xxxxxxxxxxxxxx
Subject: RE: Interface Dampening [bcc][faked-from][bayes]
Importance: Low

Hi,

I'll take a crack at this.

Every time the interface flaps, it incurs a penalty of 1000 points (this
penalty amount is not configurable).  

However, you can specify the suppress amount which in your case is at least
6 x 1000 or 6000 points. (This suppress amount actually has to be lower than
6000 because the penalty starts to decay immediately.)

But, you're not done yet.  Once a penalty occurs, it starts to decay at a
rate of 1/2 the penalty amount per half life.  In other words, if the half
life is 30 minutes, 30 minutes after the penalty occurs, the penalty is only
500 points.

So, now the problem is to figure out how to get to a penalty of 6000 with 6
flaps in an hour.  If there weren't this penalty decaying aspect, this would
be easy.  But, with this decaying aspect, the answer depends on when within
the first hour the flaps occur.

If all 6 flaps occur in the last minute of the hour than there won't be much
time for the penalty to decay much so if your suppress level is should be
something like this:

total penalties - decay amount > suppress level

So, in your case, total penalties is 6000.  Decay amount depends on half
life where the greater the half-life, the smaller the decay amount.  So, if
you set the suppress level to 5001 and set a very large half you should be
OK.

HTH, Tim


-----Original Message-----
From: nobody@xxxxxxxxxxxxxx [mailto:nobody@xxxxxxxxxxxxxx] On Behalf Of
buesink@xxxxxx
Sent: Thursday, July 14, 2005 4:49 PM
To: ccielab@xxxxxxxxxxxxxx
Subject: Interface Dampening

Hi there,

I've a question, I'm playing with interface dampening. 
And I am always messing things up with it ;-)

I want to do the following:

If an interface flaps 6 times within an hour, then I want to dampen it.

How can I set this up?


Regards!

_______________________________________________________________________
Subscription information may be found at: 
http://www.groupstudy.com/list/CCIELab.html

_______________________________________________________________________
Subscription information may be found at: 
http://www.groupstudy.com/list/CCIELab.html