[j-nsp] router reflector clients and non-clients

Victor Sudakov vas at mpeks.tomsk.su
Wed May 30 04:02:24 EDT 2018

Alexander Marhold wrote:
> >Instead you should not even connect RR1 and RR2 together 
> >And treat RR infrastructure built from RR1s I their respective clusters as
> a
> >separate infrastructure to RR2s.
> >This is the proper way
> This was the proper way in 1995, but not actual as...
> (Unfortunately most BGP books have been written at that time and are still
> sold...)
> Never do this as it can lead to missing routing updates if a client A is
> connected to RR-1 only and Client B connected to RR-2 only ( because of link
> outages) then A does not get the routes from B and vice versa
> Therefore---- make each RR with a unique cluster-id ( recommended identical
> to router-id ) and then you can either make a normal ibgp connection between
> both RRs or each one is the client of the other one

But in this scenario, a client will send an update both to RR1 and
RR2, and RR1 will reflect this update to RR2, and RR2 will reflect it
to RR1, and voila! We have a routing loop.

> There are nice explanations on the Internet backing me up ( Ivan Peplnjak,
>  http://packetpushers.net/bgp-rr-design-part-1/ 
> http://orhanergun.net/2015/02/bgp-route-reflector-clusters/

Thanks, will read those.

Victor Sudakov,  VAS4-RIPE, VAS47-RIPN

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