BGP TTL

[john heasley]

Thu, Mar 21, 2002 at 09:17:13AM +0100, 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/

looks like a lot of polution to me.  we do not leak communities handed
to us from ebgp or our numerous internal markings.

2914:410		<<<<< our route or learned from a customer
        unknown
  
        learned from AS2914 (6828 routes)
2914:420		<<<<< learned from a peer
        unknown
  
        learned from AS2914 (83100 routes)

any other 2914: marking is rogue.

> 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