Not only do /24's run amuk...

Wed Jan 28 13:33:10 UTC 2004

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
>