[46224] in North American Network Operators' Group
Re: Survey on IBGP persistent route oscillation problem
daemon@ATHENA.MIT.EDU (Danny McPherson)
Thu Mar 21 11:37:55 2002
Message-Id: <200203211626.g2LGQED05460@tcb.net>
To: nanog@merit.edu
From: Danny McPherson <danny@tcb.net>
Reply-To: danny@tcb.net
Date: Thu, 21 Mar 2002 09:26:14 -0700
Errors-To: owner-nanog-outgoing@merit.edu
> We have a similar situation (RR + always-compare-MED off), and the BGP table
> version keeps changing at 1K/min (http://performance.cn.net:2003/). I
> suspect some
> route meet the criteria of IDR-oscillation draft. But in real world, it's
> very hard to pick
> up the pattern depicted in the draft from a huge log of debug bgp output.
It's actually quite trivial to identify. Have a look at:
http://www.cisco.com/warp/public/770/fn12942.html
Juniper syntax would result in the same..
> 1. How many time do our operator really find and affected by the
> problem depicted in draft-ietf-idr-route-oscillation-01.txt
I know of more than a few, and would bet that if additional folks
took the time to look, they'd realize it was occurring as well.
> 2. From my experience, most flapping seems to be oscillation route
> which escaped the eBGP damping protection. And for this, we need
> adjust damping parameters from RIPE 220 to make up.
Nope. Dampening doesn't resolve this because it occurs
intrA-domain.
> 3. Anyone see oscillation been magnified when injected
> into RR (cluster structure) ?
Not sure I understand what you mean by "magnified"?
Have a look at the Cisco FN, it's useful in understanding and
identifying the problem.
-danny
