Re: Cluster-ID and Originator-ID of group RR

Brian,
I think there are cases where it does matter.

I don't think there's a way to actually create a loop, no matter what
the configuration is. Once an update passes through a RR, the Cluster-ID
sticks and will not be forgotten. Originator-ID, on the other hand, will
be overwritten when going through another RR.

The only wrong-doing I can think of is using the same Cluster-ID for two
RRs that are not actually a cluster, i.e., that do not have the same set
of clients. If you do, some clients will not have full route info.

-Carlos

Brian McGahan @ 23/07/2012 11:34 -0300 dixit:
> Even if you don't configure a cluster-id it is inherited from your router-id. The only case where you really need to configure the cluster-id manually is when you have multiple route reflectors in the same cluster. Specifically this means that you would have two or more route reflectors that are servicing the same set of clients, and are also peering with each other as either clients or non-clients. When the route reflectors reflect the same set routes to each other, they will drop the incoming updates if they share the same cluster-id.
>
> Really at the end of the day it doesn't matter how you configure it, because BGP will eventually stop the looping of updates either based on the originator-id or the cluster-id. The only difference is how far the update message is passed around before it is dropped. Also remember this is just a loop of control plane information, not of the data plane. In other words you could basically configure a full mesh of iBGP peers with every router as a route reflector, and each of their peers are clients, and the network would eventually work itself out.
>
> Brian McGahan, CCIE #8593 (R&S/SP/Security)
> bmcgahan_at_INE.com
>
> Internetwork Expert, Inc.
> http://www.INE.com
>
>
> -----Original Message-----
> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of jeremy co
> Sent: Monday, July 23, 2012 3:57 AM
> To: Cisco certification
> Subject: Cluster-ID and Originator-ID of group RR
>
> Hi,
>
>
> I understand that Originator-ID is a new way of detecing loop in group of Route reflectors insteadof cluster-ID
>
>
> So if I have a scenario of group of RRs, to my understanding there is no need for cluster-ID to be configured under BGP process and originator-ID will take are of it.
>
>
>
> Is that a correct assumption ?
>
>
> thanks.
>
>
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-- 
Carlos G Mendioroz  <tron_at_huapi.ba.ar>  LW7 EQI  Argentina
Blogs and organic groups at http://www.ccie.net