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.
Date: Tue, 18 Jun 2002 20:13:50 -0400
From: Thomas Kernen
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)
Analysis and mild tuning. Perhaps I'm strange, but this is one
of thing things that I consider pre-sale when working with a
provider with which I'm unfamiliar. It's not a deal-breaker,
but is something to which I pay attention.
Note that this is most significant for Web content providers,
for obvious reasons.
Several providers tag internally, although some do not disclose
their tags. Granularity and detail vary widely. (Compare C&W
with GBLX, for example.)
Eddy
Certainly do.. debugging and analysis yes, the communities also determine
what we announce to who eg if its tagged as a peer route dont announce to
other peers
Our customers also like them as they can make decisions about our routes
without the benefit of all the BGP info such as next hop exit point from
our network
Steve
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:
Many providers document their communities
on webpages:
eg:
http://info.us.bb.verio.net/routing.html#communities
http://cw-rr.cw.net/community_receive.htm
http://cw-rr.cw.net/community_announce.htm
you probally just need to find the uunet specific webpage
as it realtes to this.
- jared