Ok.......it seems this topic is divided ....
1.GBP flaps/flapping
2.flapping in general
as regards 1 i don`t claim to know the answer but....
i think a FAIR description of a flapping route/interface would be this
"the route has gone down and come back up again BEFORE the router has had
time to Re-converge/update routing tables"
with singular instances bieng a "flap" and multiple instances bieng
"flapping"
????Would this be a fair overall description.....if i am right then it`s a
small step to finding out why/how BGP does it
Thanks
steve
>From: "ElephantChild"
>Reply-To: "ElephantChild"
>To: [EMAIL PROTECTED]
>Subject: RE: BGP Dampening, What is a flap? [7:1128]
>Date: Thu, 19 Apr 2001 20:39:20 -0400
>
>On Thu, 19 Apr 2001, Priscilla Oppenheimer wrote:
>
> > It doesn't answer the question. It says there's a penalty for each flap.
>Is
> > there a penalty for
> >
> > 1. each time a route goes down
> > or
> > 2. each time a route goes down and back up
> >
> > The answer is probably number 2, as the orignal poster thought also,
>since
> > just going down isn't really "flapping."
>
>Well, maybe I'm missing something, but I don't see how a route could go
>down more than once without going up meanwhile, or up more than once
>without going down meanwhile. So 1 and 2 are pretty much the same thing,
>except perhaps for an extra up or down at either end. OTOH, it could be
>that some BGP implementations send several WITHDRAWS in a row, or that a
>single route going down may result in a given router getting several
>withdraws (eg, redundant route reflectors, or multiple peers advertizing
>the same prefix). Does someone know whether 1- BGP protocol definition
>allows sending several WITHDRAWS to the same peer for a single up-down
>transition and 2- routers apply the flap penalty repeatedly when they get a
>WITHDRAW for a prefix already marked down?
>
>--
>"Someone approached me and asked me to teach a javascript course. I was
>about to decline, saying that my complete ignorance of the subject made
>me unsuitable, then I thought again, that maybe it doesn't, as driving
>people away from it is a desirable outcome." --Me
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