10-03-2010 05:28 PM - edited 03-04-2019 09:58 AM
Hello Dear Experts,
I have a question about the BGP redundancy link to two links to same ISP.
We are the transit to our customers. One of our customer has to connected to our Europe link. This customer also has
other link to other ISP to Europe link. The europe links connected to same ISP (TTK). Customer wants to do redundant
these two links. But the bgp with this customer and us is always up when our europe link has down. We have announced
default to customer by default originate command. We got the full table from TTK. When TTK link is down customer didn't
know about it. I think they used localprefence to our link.
How to decide this issue? Please any idea about this?
Thank you
Bayanmunkh
Mongolia
10-03-2010 05:58 PM
Hi Bayanmunkh,
Your requirement here is stop advertising of default route to customer when your europe link goes down.
Now question to you. ....along with full routing table do you have accepted default route from TTK, If so instead of using default originate you can use
route-map to advt. default route to customer
like
ip prefix-list default permit 0.0.0.0/0
route-map DEFAULT-OUT permit 10
match ip address prefix-list default
router bgp xxxx
neighbor X.X.X.Y route-map DEFAULT-OUT out
This will remove default from customer bgp table once your europe link goes down.
Regards
Mahesh
10-03-2010 08:57 PM
Dear Mahesh Gohil,
Thanks a lot for your reply. It is very helpful answer. But we got only full bgo table from europe not included default. Also we got 0.0.0.0/0 from other
router that facing to USA. Here:
Routing entry for 0.0.0.0/0
Known via "ospf gemnet", distance 110, metric 10, candidate default path, type extern 2
Installed Sep 26 08:07:33.784 for 1w1d
Routing Descriptor Blocks
180.149.95.217, from 180.149.94.245, via GigabitEthernet0/0/0/0
Route metric is 10
No advertising protos.
And we set the weights to routes from europe higher that internal reason. I understand that we need to Full table+default from europe now? Is this
cause any problem that two default routes on same router. Do we need anything else?
Thank you very much
Bayanmunkh
10-03-2010 09:31 PM
Hi Bayanmunkh,
Another way is to put default route toward your europe peering and redistribute same to your bgp by "redistribute static route-map"
in global bgp while keeping default route-map with your customer bgp.
otherwise it is not possible to inform your customer to widraw default route if your peering goes down.
ultimately you need to relate your default route to that of peering by any means.
Regards
mahesh
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