BGP communities usage for route origin, entry point

Wed Jun 19 08:32:19 UTC 2002

You can find an analysis of the utilization of communities found in 
routing tables collected by RIPE RIS and RouteViews at 
http://www.infonet.fundp.ac.be/doc/reports/Infonet-TR-2002-02.pdf. In 
this analysis we show two things: (1) communities tend to be widely used 
and (2) communities are used for route tagging (for instance to remember 
where a route has been issued and traffic engineering purposes (for 
instance to influence how a peer will redistribute our routes).

The results of the analysis are available from 
http://alpha.infonet.fundp.ac.be/anabgp

By the way, we have presented our work during the last NANOG meeting in 
Toronto. The slides are available from 
http://www.nanog.org/mtg-0206/bruno.html

Bruno.

Thomas Kernen wrote:

>
>This started off as me being curious as to why a UUNet engineer I was
>talking to told me he could not understand why a network would support a
>feature such as BGP communities for identifying the origin of a
>route/network entry point. I tried to explain to him the advantage of being
>able to quickly identify where a route originates from (geographically),
>type of interconnect, type of "peer" (in this case I use peer for any BGP
>peer, customer or transit). I explained that it could be usefull for
>debugging and gaining more background info (route analysis is one of my
>favorite tasks) and some of the major and minor networks do provide such a
>feature/service.
>
>Still the engineer could not understand why and only saw this as a security
>issue, well I guess when you work for a network that does not provide any
>public looking glass or route server it's not really a surprise </rant>
>
>This triggered a thought, do many people actually use BGP communities to
>pinpoint a route origination point/type, and if so for what purpose
>(debugging, analysis, other)
>
>Thomas
>
>PS: If UUNet do actually support this feature please tell me who I should
>contact.
>