12-16-2010 06:46 PM - edited 03-04-2019 10:49 AM
Dear Gurus,
I have some questions regarding RR design before i simulate it.
Diagram Informations
CORE-1 and CORE-2 - direct interface with GW routers (GW routers goes to ISP)
RR-1 and RR-2 - are for route reflector
ACC-1 and ACC-2 - are access gateway routers for clients
Questions
1. Since RR-1 will do ibgp only to GW-1 and GW-2 and RR-2 will do ibgp only to GW-3, GW-4 and GW-5, how will both RR's share bgp routes?
Is it ok to rrclient RR-2 to RR-1 and vice versa?
2. ACC-1 and ACC-2 are rrclient of RR-1 and RR-2, how will the path goes? will it still pass through RR-1 and RR-2. It should be ACC-1 going to CORE-1 and then GW.
For now i want to clear this things first. Hoping your support.
Thanks.
Jeff
12-16-2010 08:05 PM
Jeff,
Since you have 2 different RRs, then you need to different RR clusters. For example RR-1 can be cluster 1.1.1.1 and RR-2 can be cluster 2.2.2.2.
In order for these to work correctly, you will also need an IBGP connection between RR-1 and RR-2
HTH
Reza
12-16-2010 08:13 PM
Hi Reza,
Thanks for the info, so ibgp between the 2 RR's will do the sharing of routes? Or i will still configure each RR as client for each other?
Thanks.
Jeff
12-16-2010 10:05 PM
Hi Jeff,
There are two approch for RR design:
1- Putting both RR in same cluster:
> Here you do not need to configure RR as a client. A normal full-mesh IBGP is required between
two RR.
> A route will be learned from a PE at both RR
> One RR will ignore the route learned from other RR due to cluster-list attribute
2- Putting both RR in different cluster"
> Even Here you do not client config because as per IBGP split-horizon rule route learned from client will be propogated to all peers except the sender
Hope this helps
Regards
mahesh
12-17-2010 12:09 AM
Hi Mahesh,
For these topology there are no physical conection with both RR's. So you mean i would just enable ibgp on both RR and they will share routes? Coz both RR's learned internet routes via ibgp so it cannot be redistributed again via ibgp?
Thanks.
Jeff
12-17-2010 04:53 AM
Hi jeff,
Irrespective of physiclal topology you need full-mesh ibgp peering between RR's
Regards
Mahesh
01-02-2011 05:45 PM
Hi Mahesh,
already simulated it on gns3, to share the routes, i made both RR's as client also. is this ok? is there any problem in here just in case i run this on real scenario? Also, what pitfalls i should look at ?
Thanks.
Jeff
01-02-2011 07:05 PM
Jeff,
Yes, the connection between the 2 route reflectors is just a normal IBGP session. There is nothing special about it.
HTH
Reza
01-02-2011 07:14 PM
Hi Reza,
Thanks for the reply, im just thinking of any routing loops that may cause problem. How bout the command " no bgp client-to-cliet-reflection",where is this use for?
Thanks a lot.
Jeff
01-02-2011 07:29 PM
Hi Jeff,
You don't need no bgp client-to-client reflection.
This is used only when the local RR neighbors are fully meshed
have a look at this link for an example.
http://www.cisco.com/en/US/docs/ios/12_3t/ip_route/command/reference/ip2_b1gt.html#wp1076671
In your case, you just need a simple IBGP session between the 2 RRs and since each RR has a different cluster ID, routes will propagate from one RR to the other without being blackholed or ignored.
HTH
Reza
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