nanog mailing list archives
Re: Dampening considered harmful?
From: Mark Kent <mark () noc mainstreet net>
Date: Mon, 27 Dec 2004 18:16:24 -0800 (PST)
Back in mid-December someone typed:
One reason to be careful with dampening is that flaps can be multiplied. (Connect to routeviews and see the different flap counts under different peers for the same flap at your end to observe this.)
How about in this scenario: asA gets transit from asT asA gets backup transit (ASpath padding) from asB asB gets transit from asT asB gets transit from asJ asJ gets transit from asT asT peers with whole world(*) Now, as asA flaps to asT, we see "bad things" happen to their routes, namely an unreasonable amount of flap at even nearest neighbors to asT. Can this flap magnification be explained by the hierarchy I describe above? That is, asT treats all of these ASpaths as customer routes: asA asB_asA asJ_asB_asA and so we might expect to see multiple flaps as different "best" routes come into view inside the geographically diverse asT... right? Thanks, -mark (*)you know what I mean.
Current thread:
- Re: Dampening considered harmful? Mark Kent (Dec 27)
- Re: Dampening considered harmful? Jerry Pasker (Dec 28)