Set Route preference from two same redistributed routes from BGP

[Mark1110]

Hello,

Someone know how to Set Route preference from two same redistributed routes from BGP through different vrfs.

I have two ISPs and learning default route from them. I want ISP1's default route choose as a priority. 

I am having two vrfs for them 1) ISP1_VRF 2) ISP2_VRF

I am creating 3rd vrf  INTERNAL_VRF and created VASI interfaces to communicate with these different vrf.

Anything i can use for redistribute command so it choose ISP1's default route and use ISP2's default route for backup on INTERNAL_VRF's routing table?

-------------------------

router ospf 1 vrf INTERNAL_VRF
capability vrf-lite
area 0 authentication message-digest
redistribute bgp 512 subnets route-map ISP1-BGP-TO-OSPF

----------------------------------------------------------

ip prefix-list ISP1-BGP-TO-OSPF seq 10 permit 0.0.0.0/0
route-map ISP1-BGP-TO-OSPF permit 10
match ip address prefix-list ISP1-BGP-TO-OSPF

[Harold Ritter]

Hi @MHM Cisco World ,

I do not see anything in you configuration to make sure that ISP1 will be selected as the bgp best path. The bottom line is that the path received from ISP1 and ISP2 will be compared to one another once they are imported in VRF INTERNAL and you can't let the bgp best path be selected randomly. Also, it not useful to have a separate metric for ISP1 and ISP2 on the edge device, as the route from edge router 1 will always be preferred over the one received from edge router 2.

Regards,

[Harold Ritter]

Hi @MHM Cisco World ,

The simplified config would look something like this:

ip vrf INTER

rd 3:100

route-target import 1:100

route-target import 2:100

!

ip vrf ISP1

rd 1:100

route-target export 1:100

!

ip vrf ISP2

rd 2:100

route-target export 2:100

!

!

router ospf 10 vrf INTER

! Set metric to 1 for edge router 1 and to 2 for edge router 2

redistribute bgp 100 subnets metric 2

network 10.0.0.0 0.0.0.255 area 0

!

router bgp 100

bgp router-id 1.1.1.1

bgp log-neighbor-changes

!

address-family ipv4 vrf ISP1

neighbor 100.0.0.2 remote-as 200

neighbor 100.0.0.2 weight 65535

neighbor 100.0.0.2 activate

exit-address-family

!

address-family ipv4 vrf ISP2

neighbor 110.0.0.3 remote-as 300

neighbor 110.0.0.3 activate

exit-address-family

!

Regards,

[MHM Cisco World]

@Mark1110  mention this 

***
Primary edge router

redistribute bgp 512 subnets metric  50 route-map ISP1-BGP-TO-OSPF  

redistribute bgp 512 subnets metric  60 route-map ISP2-BGP-TO-OSPF 

secondary edge router

redistribute bgp 512 subnets metric  70 route-map ISP1-BGP-TO-OSPF 

redistribute bgp 512 subnets metric  80 route-map ISP2-BGP-TO-OSPF 

***
this what I was try  to solve, 
using 
redistribute bgp 100 subnets metric 2 
will make the subnet from other ISP have same metric. 

[Harold Ritter]

Hi @MHM Cisco World ,

I think his thought was that the two local default route from ISP1 and ISP2 would be injected in ospf, but as I mentioned, bgp will only select one of the two default routes on each edge router and the one from ISP1 should be preferred (done with the bgp weight). So there is no need to inject with 4 different metrics. We only need to redistribute with a higher metric on edge router 2, so the route learnt from edge router 1 is always preferred.

Regards,