R1 is at the central site and has the data center hosted. The link between R1 and R2, R2 and R4 are in Area0. The links between R1 and R3, R3 and R4 are in Area1.
Users at R4 wants to access some SAP servers which are hosted at R1. The link between R4 and R2 is a slow speed link and the link between R4 and R3 is a 2 MBPS LL.
The problem is that the R4 is learing the routes to the SAP servers segment Via R2 with slow speed links (a backup link) and hence users are facing a problem to access the SAP application.
We have tried changing the cost on the R2 and R4 interfaces from default 48 to 1000 and more but still it learns the route Via R2. When we shut the interface down at R4, the router learns the route via R3 (which it should be and what we want) everything works fine.
Let me know your thoughts on this and how can we fine tune that.