re: bgp best path confusion

Hi

this looks like a great design...isn't Route-Reflector supposed to remove the need for Full-Mesh ??

anyway, I think in this case Rule #12 applies :

12. If the originator or router ID is the same for multiple paths, prefer the path with the minimum cluster list length.
This is only present in BGP RR environments. It allows clients to peer with RRs or clients in other clusters. In this scenario, the client must be aware of the RR-specific BGP attribute.

best regards,
Gilles.

> Message du 29/08/12 C 19h01
> De : "oo IPX"
> A : "Cisco certification"
> Copie C :
> Objet : bgp best path confusion
>
> i have a hub and spoke topology, R1 being hub.
>
> R1-is a Route reflector.
>
> also, R1, R2 and R3 are fully meshed ibgp peers. with R1, R2 and R3
> advertising networks 1.0.0.0/8, 2.0.0.0/8 and 3.0.0.0/8
>
> *on what level of the bgp path decision making the following route is been
> chosen?*
>
>
>
> *R3(config-router)#do sh ip bgp 2.0.0.0
> BGP routing table entry for 2.0.0.0/8, version 4
> Paths: (2 available, best #2, table Default-IP-Routing-Table)
> Flag: 0x820
> Not advertised to any peer
> Local
> 10.1.12.2 (metric 1) from 10.1.13.1 (1.1.1.1)
> Origin IGP, metric 0, localpref 100, valid, internal
> Originator: 2.2.2.2, Cluster list: 1.1.1.1
> Local
> 10.1.12.2 (metric 1) from 10.1.12.2 (2.2.2.2)
> Origin IGP, metric 0, localpref 100, valid, internal, best
> *
>
>
> Network Next Hop Metric LocPrf Weight Path
> *>i1.0.0.0 10.1.13.1 0 100 0 i
> ** i2.0.0.0 10.1.12.2 0 100 0 i
> *>i 10.1.12.2 0 100 0 i*
> *> 3.0.0.0 0.0.0.0 0 32768 i
>
>
>
> Regards
>
>
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Received on Wed Aug 29 2012 - 21:25:39 ART