From: Brian McGahan (bmcgahan@internetworkexpert.com)
Date: Fri Jun 27 2008 - 10:54:30 ART
You should statically set the BGP router ID to a globally significant
address on the router. The cluster-ID is inherited from router-id
regardless if you hardcode it or the router-id though.
Brian McGahan, CCIE #8593 (R&S/SP/Security)
bmcgahan@internetworkexpert.com <mailto:bmcgahan@internetworkexpert.com>
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cciestruggle wrote:
> Hello Brain,
>
> We do need to have the cluster id on the router reflectors to avoid
> loops ? right?
>
> And further more do we need to explicitly specify the cluster id? the
> command reference says that it is automatically set to the local
> router id (of which reflector ?)
>
> http://www.cisco.com/en/US/docs/ios/iproute/command/reference/irp_bgp1.html#wp1012377
>
> Zealot
>
> On Fri, Jun 27, 2008 at 3:52 PM, Brian McGahan
> <bmcgahan@internetworkexpert.com
> <mailto:bmcgahan@internetworkexpert.com>> wrote:
>
> You can, but you don't necessarily have to. Most large scale route
> reflection designs include a full mesh of peerings between
> clusters via
> the route reflectors, but the route reflectors are not clients of each
> other. This means that if reflector A peers with reflector B, and
> reflector B peers with reflector C, reflector C cannot learn a route
> from reflector A's cluster through B's cluster, because if A is a
> non-client of B, B cannot advertise an iBGP route from A to C.
> However
> if these is a full mesh of non-client iBGP peerings between A, B,
> and C,
> reflector C wouldn't need to use B to get to A, since it has a direct
> peering.
>
> Ultimately for production it depends on your redundancy design.
> Technically you can have every single router be a router reflector
> with
> everyone else beings its clients. You won't cause any routing loops,
> since the cluster list prevents this, but instead you'll just have
> a lot
> of unnecessary route replication. However when we are talking about
> update messages in the order of 300,000 routes for the full BGP table,
> scalability from a resource management perspective is highly
> affected by
> route reflection design.
>
>
> HTH,
>
> Brian McGahan, CCIE #8593 (R&S/SP/Security)
> bmcgahan@internetworkexpert.com
> <mailto:bmcgahan@internetworkexpert.com>
> <mailto:bmcgahan@internetworkexpert.com
> <mailto:bmcgahan@internetworkexpert.com>>
>
> Internetwork Expert, Inc.
> http://www.InternetworkExpert.com
> Toll Free: 877-224-8987 x 705
> Outside US: 775-826-4344 x 705
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> Live Chat: http://www.internetworkexpert.com/chat/
>
>
> ccie wrote:
> > Hi experts,
> >
> > Assume I have 5 router within the same AS, and two of them will
> have IBGP
> > peer with the rest, So I configure these two with the same bgp
> cluster-id,
> > and configure the rest to be their route-reflector-clients. Should I
> > configure these two to be route-reflector-clients to each others!!!
> >
> > Thanks in advance
> >
> > Amin
> >
> >
> >
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