BGP Route Damping

Pete Templin templin at urdirect.net
Tue Nov 13 18:09:04 UTC 2001


On Tue, 13 Nov 2001, German Martinez wrote:

> Perhaps this document was already discussed (I'm new in this list).  If it
> was please let me know.  Basically, I wanted to get an opinion from US
> based ISP about this document.
> 
> Does somebody know how Tier-1 networks implement route damping ? 
> 
> Here is the document:
> 
> http://www.ripe.net/docs/ripe-210.html

I can't speak for any large networks, but I will say that you need to
adjust a portion of that configuration to actually achieve dampening of
/24s and longer.  In:

route-map graded-flap-damping permit 20
 match ip address prefix-list min24
 set damp 30 750 3000 60

you will need to change the numbers in the final line, as there is a
fundamental equation that needs to be followed:

2x(max-suppress/half-life) must be greater than (suppress/reuse).

So you'll need to increase either the max-suppress (60) or the reuse
(60), or decrease the half-life (30) or the suppress (750).

Pete

--
Peter J. Templin, Jr., CCNP, CCDP
Networking Consultant

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