DR/BDR is per broadcast subnet. In simple words if a router have 2 Ethernet interfaces with OSPF enabled (with default network type), it will have DR/BDR election in both the interfaces. It might also be posisble that the router is DR in one interface while DROther in other interafce.
In your topology, RTA will have DR/BDR election happening on 2 interfaces (10.4.0.1 and 10.5.0.1) while RTB will have DR/BDR election happening on 1 interface (10.5.0.2).
Regarding the DR/BDR selection, it uses OSPF priority or RID (if priority is same) to elect DR/BDR.
Just to add a little some, the Point-to-Point link does not elect a DR/BDR because there are only two devices therefore there is no need for this, however you can change this behavior (which would be non-nonsensical in real world) by changing the opsf interface type.
This is actually a pretty cool feature, i didn't even know it existed until I was looking for a solution to advertise a subnet (prefix in BGP talk), only if a certain condition existed. This is exactly what conditional advertisements does
j ai une question j ai achete un routeur cisco 887VA-k9 , je le configuré avec la configuration ci- dessous
si je le lier avec mon pc portable sur l un de ses ports directement ça marche toute est bien ( la connexion internet + m...
Attached policy provides CLI access to the Cisco 4G router over text messaging. Two files are in the attached .tar file:
2. PDF with instructions on how to load and use the .tcl file.