Re: BGP community settings in the real world

[Olivier Bonaventure <Olivier.Bonaventure () info fundp ac be>]

Adam,
> To what extent does setting communities on BGP routes work in the real
> world?
>
> I can't help suspecting that in reality, routes would get aggregated,
> or communities would be dropped or replaced, somewhere between source
> and destination.

In order to prepare an IETF draft on the utilization of 
extended communities to control the redistribution of routes
(see http://www.infonet.fundp.ac.be/doc/reports/draft-bonaventure-bgp-redistribution-02.txt)
we did a study of the utilization of the community attribute
for traffic engineering purposes. This study was based on two
sources of information :
 
- the RIPE whois database for the advertised communities
- the BGP routing tables collected by RIPE and routeviews

This analysis shows that BGP communities are becoming frequently
used for traffic engineering purposes. A summary of our findings
is available as 

http://www.infonet.fundp.ac.be/doc/tr/Infonet-TR-2002-02.html

and you can find the analysed data on the web as well, see

http://alpha.infonet.fundp.ac.be/anabgp/


Our intention is submit this analysis as an informational RFC one
day to document the common utilizations of the community attribute
in today's Internet. Comments on the above mentionned report
are welcome.


Best regards,


Olivier Bonaventure

---
http://www.infonet.fundp.ac.be