07-20-2020 03:47 PM
Hi,
If the ACI fabric receives the same route (0.0.00.0) through two different border leafs using two different protocol eBGP and OSPF, how does the border leafs decide to take which path.
Link to any documentation would be really helpful
LEAF 107, 108 - EBGP -RECEIVING DEFAULT-ROUTE 0.0.0.0 from INTERNET
LEAF 105,106 - OSPF - RECEIVING DEFAULT-ROUTE 0.0.0.0 from other Data center
The Leaf 105 & 106 preferring the OSPF Route instead of iBGP (MP-BGP) route. The leaf 105 &106 is preferring the locally originated OSPF route. How do we change this approach so that leaf 105 & 106 prefer the eBGP default-route.
Thank you in advance
Regards,
07-20-2020 11:48 PM
Hi @NAGA1
Do you need the 0/0 prefix learned from the other DC (through OSPF)? It would be much easier to simply filter out (through import route control) or simply not advertise the default route through OSPF.
Alternatively, you can change the AD of OSPF routes to a higher value then iBGP. This is being done through VRF -> OSPF Timers policy -> create a new policy -> change the AD.
However, I think it will still be a better routing design to simply filter out the 0/0 route, unless some requirement to be there as a backup or something.
Stay safe,
Sergiu
07-21-2020 04:55 AM
Hi, Thanks for the reply
Do you need the 0/0 prefix learned from the other DC (through OSPF)? YES ( As a backup route)
It would be much easier to simply filter out (through import route control) or simply not advertise the default route through OSPF. ( We want other DC OSPF default-route must be available in the entire fabric as a backup route so that if local internet default-route unavailable then the fabric will pick the OSPF default-route.
Alternatively, you can change the AD of OSPF routes to a higher value then iBGP. This is being done through VRF -> OSPF Timers policy -> create a new policy -> change the AD. ( We changed the OSPF AD is 201 however it was not working)
07-21-2020 05:49 AM
Hmm ok. Let me test that in the lab.
Sergiu
07-22-2020 01:06 PM
Thanks.
08-06-2020 03:39 PM
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