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Re: BGP communities usage for route origin, entry point

  • From: Bruno Quoitin
  • Date: Wed Jun 19 04:40:03 2002

You can find an analysis of the utilization of communities found in routing tables collected by RIPE RIS and RouteViews at 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

By the way, we have presented our work during the last NANOG meeting in Toronto. The slides are available from


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

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)


PS: If UUNet do actually support this feature please tell me who I should

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