BGP TTL

[Olivier Bonaventure]

Hello,

> Wed, Mar 20, 2002 at 05:30:17PM -0500, Andrew Partan:
> > On Wed, Mar 20, 2002 at 03:25:23PM -0500, Martin, Christian wrote:
> > > Perhaps communities should become mandatory transitive attributes?
> >
> > That is not a good idea.  You still need to block communities you use
> > internally so others can't effect your router.
> > Ideal provider config is
> >       - strip all communities you use for internal markers on input
> >       - act on all communities you tell you customers they may use
> >       - strip all your communities on output
> 
> >       - let all other communities thru untouched


It would probably be useful to think about using the extended communities instead
of the normal communities since extended communities will be easier to handle,
see e.g. the transitive/non-transitive bit.
 
> do folks (teir-1s) actually leak customer initiated/added communities
> through to their peers?  any actually listen to communities from their
> peers?

We did a survey of the utilization of the BGP communities based on the RIPE
whois database and on the BGP tables collected by RIPE RIS and Routeviews
in January. This survey shows that many ISPs support communities and have defined
their own communities, including tier-1 ISPs and that several ISPs allow
those communities to leak through their peer. More information about this
survey is available in an internet draft that will be officially announced next week
but is already available as :

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

The raw data summarised in the survey is available from

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

If you would like to have other informations about the utilization of the
BGP communities, let us know.

Best regards,

Olivier Bonaventure

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