[66853] in North American Network Operators' Group
Re: Not only do /24's run amuk...
daemon@ATHENA.MIT.EDU (Stephen J. Wilcox)
Wed Jan 28 08:33:50 2004
Date: Wed, 28 Jan 2004 13:33:10 +0000 (GMT)
From: "Stephen J. Wilcox" <steve@telecomplete.co.uk>
To: "Anton L. Kapela" <kapela@mwdt.com>
Cc: nanog@merit.edu
In-Reply-To: <1511.216.82.101.101.1075248060.squirrel@www.mwdt.com>
Errors-To: owner-nanog-outgoing@merit.edu
Hi Anton,
I suppose its to be expected that smaller blocks will flap more than larger
ones if you consider that if I have a /8 I'm likely injecting the /8 into BGP
from a lot of core routers and so its unlikely that I'll have a problem which
takes out enough routers for my route to withdraw, by contrast I'd expect a /24
to be sourced from probably a single point and hence be affected by any issue at
that particular PoP,
just my 2-euros :)
Steve
On Tue, 27 Jan 2004, Anton L. Kapela wrote:
>
>
> ...They seem to come & go as they please!
>
> Inspired by RAS's prior posts regarding /16's that were hastly de-agged, I
> took some time this weekend to answer a few questions which came up; how
> many updates do I hear about a specific prefix, and does the length have any
> relationship? Well, several hours later, I knew pretty straight away how
> many updates I heard about various prefixes in the STS Telecom looking
> glass, at least.
>
> Consider this v0.0.1-alpa of the "Most-Heard Prefix" list, a sort of
> web-based and rule-less implementation of 'sh ip bgp flap-statistics.'
>
> The sorted list, updated every 60 minutes, is available here in gzip format
> due to excessive size (indeed, 10 peers act as a amplifier):
>
> http://eng.ststelecom.com/bgp-data/top-prefixes.txt.gz
>
> Incidently, many of the most-updated prefixes are included in the list of
> RAS's /16 de-aggs.
>
> Todo: ignore the effects of a peer session resets (i.e. don't consider a
> reload as part of the per-prefix flap count) and look at path changes with
> each update (is it a normal flap, or mid-day traffic-engineering session
> gone wrong?).
>
> Any comments or suggestions for changes are very welcome; please reply
> off-list.
>
> Thanks,
>
> --Tk
>
