From: Toh Soon, Lim (tohsoon28@gmail.com)
Date: Mon Jul 30 2007 - 06:26:16 ART
Hi Scott,
Without the existence of the same cluster ID, I believe there's still some
degree of loop prevention mechanism. e.g. the ORIGINATOR_ID?
If redundancy/backup is my primary design goal, should I go for different
cluster ID, i.e. your point #1 ?
Thank you.
B.Rgds,
Lim TS
On 7/30/07, Scott Morris <smorris@ipexpert.com> wrote:
>
> The existence of the same cluster ID will be seen as a BGP loop on any
> received routes by the BGP process... So current best practice thinking
> is
> to make your cluster ID's deliberately different for this reason.
>
> Otherwise, if the loop elimination is part of your design (e.g. not really
> backup), then by all means make them equal. That was the former best
> practice concept. :)
>
> HTH,
>
>
> Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, JNCIE
> #153, CISSP, et al.
> CCSI/JNCI-M/JNCI-J
> VP - Technical Training - IPexpert, Inc.
> IPexpert Sr. Technical Instructor
>
> A Cisco Learning Partner - We Accept Learning Credits!
>
> smorris@ipexpert.com
>
> Telephone: +1.810.326.1444
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>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Toh
> Soon, Lim
> Sent: Monday, July 30, 2007 12:50 AM
> To: Group study
> Subject: Potential Issue Configuring BGP Cluster ID
>
> Hi All,
>
> In a BGP route reflector design with dual RRs and all RR clients have iBGP
> sessions to both RRs, what's the implication if I don't configure both RRs
> in the same cluster (using the command "bgp cluster-id")?
>
> If both RRs are configured to the same cluster ID, I notice the following
> issue:
>
> If the BGP sessions between Client1-RR2 and Client2-RR1 are down at the
> same
> time, Client1 would not be able to learn the routes from Client2 and vice
> versa, due to the fact that the RRs will ignore each others' routes after
> seeing its own cluster ID in the CLUSTER_LIST.
>
> Kindly shed some light on the above issue, and whether it's advisable to
> configure the RRs in the same cluster.
>
>
> Thank you.
>
> B.Rgds,
> Lim TS
>
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