nanog mailing list archives

Re: Open Source BGP Route Optimization?


From: Olivier Bonaventure <Bonaventure () info ucl ac be>
Date: 29 May 2004 15:11:22 +0200


Sam,

You can get the received routes via SNMP. I've done this manually on
occasion for the purposes of doing "what-if" analysis of potential
traffic plans - take a dump of all available external routes via SNMP,
apply to that the proposed policy with regard to selecting the best
route, then correlate the resulting route choices with known traffic
statistics to determine the resulting utilisation levels of each
external link. This has proven useful in a number of situations where
radical changes to external routing were being made, to avoid
unexpectedly overloading particular links.

I would had liked to had been able to have done such things in the past. I
was thinking about having a go at writing something, but it's not like I
have enough time as it is, and our network isn't really big enough to
warrant it.

Though I am interested in what tools already exist to support this (more out
of curiousity than need). 

C-BGP (http://cbgp.info.ucl.ac.be) developped by Bruno Quoitin, can be
used to perform this kind of analysis. It can import the BGP routes in
MRTD format, but other formats can be easily converted to the MRTD
format. C-BGP allows you to build a model of your network that considers
both the IGP, the iBGP and eBGP sessions as well as the BGP routing
policies that you use. Each C-BGP router is configured by using a
Cisco-like syntax that should be familiar to most network engineers. One
the model has been written, you can use it to perform different types of
what-if analysis such as :
- impact of IGP weight change
- impact of the loss of one eBGP session
- impact of the addition of a new peer/provider

If there are other types of analysis that you would like to be able to
perform in your network, let us know...

Best regards,


Olivier Bonaventure
-- 
CSE Dept. UCL, Belgium - http://www.info.ucl.ac.be/people/OBO/


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