but I need to create the VLANs on my edge router E1, what I don't want to do, or I should create the subinterfaces on E1's physical interface and put them in different vlan.

both aproaches need much more changes that I'd like to make.

Two VLANs is much less of a kludge than any other alternative I can think of.

You have not given any info on your topology - I assume your E1 router is connected to a switch and then on to the D routers?

If so, move one of the D routers to a new VLAN (with conesquent new IP address).

You have two choices, depending on what the E1 router is. If you have a spare LAN you can add that to the switch, put it in the new VLAN and configure appropriately.

The other option (indeed the one I would probably go with) is to configure the link between E1 and the switch as a trunk and use subinterfaces to the two VLANs. Then pick the one that you don't want to use, and increase the cost (increasing it by one will do). I would do it at both ends to ncourage the traffic in both directions.

Believe me, this is much less work in the long run than trying to convince OSPF that a LAN is something it isn't!

Paul.

I don't wan to override the OSPF's route selection, I just want to give the different cost to the prefixes that I get from my neighbours.

I think also it should be possible to do somehow with route-maps but it means I should put the whole traffic via PBR and it's not the best solution I think.