bgp best path compare-routerid implementation example

Andy Davidson andy at
Fri Sep 25 07:21:22 UTC 2009

On 25 Sep 2009, at 05:24, devang patel wrote:

> I am looking for the *bgp best path compare*-*routerid* implementation
> example? I know the function of it but looking for some scenario  
> where its
> been used...

Hi, Devang

This option is really only used in order to instruct a router to skip  
the option before it in best path selection algorithm (prefer the path  
learned from the older established session).

I don't think you'd use it if you ran a normal network (or knew what  
you were doing ;-) ) because you'd typically use much more  
deterministic decisions to send traffic to specific and predictable  
paths, or you'd use hot-potato routing and send the traffic to the  
nearest equivalent exit ('prefer ebgp over ibgp' and 'prefer path with  
lowest igp metric' comes before 'use the oldest path').


Regards, Andy Davidson       +44 (0)20 7993 1700
NetSumo  Specialist networks consultancy for ISPs, Whitelabel 24/7 NOC

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