RE: BGP damping

From: Scott Morris (smorris@internetworkexpert.com)
Date: Mon Aug 04 2008 - 20:11:51 ART


A penalty PER FLAP is 1000. but if your half-life is 5 minutes, then the
decrease will be 500 points over 5 minutes ASSUMING there is only one flap!

If there are two flaps (accumulated penalty of 2000) then over the same 5
minutes, you'd decrease roughly 1000 points.

HTH,

Scott Morris, CCIE4 #4713, JNCIE-M #153, JNCIS-ER, CISSP, et al.
CCSI/JNCI-M/JNCI-ER
Senior CCIE Instructor

smorris@internetworkexpert.com

 

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-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Hobbs
Sent: Monday, August 04, 2008 5:58 PM
To: Alberto Santos
Cc: ccielab@groupstudy.com
Subject: Re: BGP damping

The DocCD says penalty is 1000 not 500...

http://www.cisco.com/en/US/docs/ios/iproute/configuration/guide/irp_bgp_int_
features_ps6350_TSD_Products_Configuration_Guide_Chapter.html#wp1054203

The penalty is decreased by half every half-life. So if half-life is 5
minutes and your penalty is 1000, then it will be decreased by 500 over the
course of the next 5 minutes. And over the course of the next five minutes
it will be decreased by 250 and so forth. The decrease value is NOT always
the same, but the increase (1000) is.

hth,

On Mon, Aug 4, 2008 at 3:50 PM, Alberto Santos
<albertofsantos@gmail.com>wrote:

> Does anybody know how the decrease penalty works?
>
> 2008/8/4 Alberto Santos <albertofsantos@gmail.com>
>
> if you a route goes down, penalty of 500, but if it is goes down/up,
>> penalty of 1000, it can not be changed.
>>
>> 2008/8/4 Hobbs <deadheadblues@gmail.com>
>>
>>> The question was how to alter the 1000 penalty. That can't be set
>>> with a
>>>
>>> route-map. And a route-map is optional:
>>>
>>> R1(config)#router bgp 100
>>> R1(config-router)#bgp dampening ?
>>> <1-45> Half-life time for the penalty
>>> route-map Route-map to specify criteria for dampening <cr>
>>>
>>> OR:
>>>
>>> R1(config)#route-map bgp-damp
>>>
>>> R1(config-route-map)#set dampening ?
>>> <1-45> half-life time for the penalty
>>>
>>> R1(config-route-map)#set dampening 2 ?
>>> <1-20000> penalty to start reusing a route
>>>
>>> R1(config-route-map)#set dampening 2 2 ?
>>> <1-20000> penalty to start suppressing a route
>>>
>>> R1(config-route-map)#set dampening 2 2 2 ?
>>> <1-255> Maximum duration to suppress a stable route
>>>
>>> R1(config-route-map)#set dampening 2 2 2 2 ?
>>>
>>> You still can't change penalty value of 1000
>>>
>>>
>>> On Mon, Aug 4, 2008 at 3:22 PM, John <jgarrison1@austin.rr.com> wrote:
>>>
>>> > Damp parameters have to be configured in a route map with the set
>>> dampening
>>> > command
>>> > ----- Original Message ----- From: "Hobbs"
>>> > <deadheadblues@gmail.com>
>>> > To: "akyccie" <akyccie@gmail.com>
>>> > Cc: <ccielab@groupstudy.com>
>>> > Sent: Monday, August 04, 2008 12:18 PM
>>> > Subject: Re: BGP damping
>>> >
>>> >
>>> >
>>> > The default penalty is 1000 so you don't need to configure it.
>>> > And as
>>> far
>>> >> as
>>> >> I know, you can't change it.
>>> >>
>>> >> hth
>>> >>
>>> >> On Mon, Aug 4, 2008 at 10:43 AM, akyccie <akyccie@gmail.com> wrote:
>>> >>
>>> >> How to set the penatly of 1000 everytime routes flap. Not
>>> >> getting any
>>> >>> option
>>> >>> to set panelty.
>>> >>>
>>> >>> bgp dampening [half-life reuse suppress
>>> max-suppress-time]
>>> >>>
>>> >>>
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