OSPF type 1 route is always preferred over a type 2 route for the same destination so we can set metric-type 1 at Site-A RTR1 so that it is preferred over Site-B RTR2.
Note:
Routes are redistributed in OSPF as either type 1 (E1) routes or type 2 (E2) routes, with type 2 being the default.
- A type 1 route has a metric that is the sum of the internal OSPF cost and the external redistributed cost.
- A type 2 route has a metric equal only to the redistributed cost.
- If routes are redistributed into OSPF as type 2 then every router in the OSPF domain will see the same cost to reach the external networks.
- If routes are redistributed into OSPF as type 1, then the cost to reach the external networks could vary from router to router.