This may well be an OSPF design flaw by myself and I could potentially fix it but I wanted to ask if there is another way before I decide to run vlans over my router connections.
Basically I have R3 connected to R1 and R2 via an external providers fibre connection. The external provider has given me a VLAN to tag for accessing my interconnected sites.
So Site B contains R3, site A contains the switch, R1 & R2
My switch terminating the fibre has connections to both R1 & R2 untagged in the vlan that goes through to site B.
So my R3 sees neighbours R1 and R2 on the same interface.
I want to make R1 the primary route and R2 the backup for all routes.
How can I achieve this as interface cost in this case won't work as I understand it.