DR (Designated Router) is for environments where many routers on the same network such
as Ethernet. In the following presented network, all routers are reloaded simultaneously, and
DR is selected as expected. What is the RTC status?
A.
2WAY/DR
B.
FULL/DR
C.
FULL/DROTHER
D.
FULL/BDR
Explanation:
The point of this question is about the select principles of DR and BDR.
DR and BDR election is done via the Hello protocol. Hello packets are exchanged via IP
multicast packets (Appendix B) on each segment. The router with the highest OSPF priority
on a segment will become the DR for that segment. The same process is repeated for the
BDR. In case of a tie, the router with the highest RID will win. The default for the interface
OSPF priority is one. Remember that the DR and BDR concepts are per multiaccess
segment. Setting the ospf priority on an interface is done using the ip ospf priority <value>
interface command. In this case, all routers have the same priority, but RTD has the highest
RID, and RTC was followed, so RTC was the BDR.