Question 980
Four OSPF routers become eligible simultaneously on an Ethernet broadcast segment, with no existing DR/BDR: R1 (priority 50, router ID 10.255.0.177); R2 (priority 6, router ID 10.255.0.253); R3 (priority 7, router ID 10.255.0.153); R4 (priority 100, router ID 10.255.0.24). Which router wins designated router election?
Explanation
Correct Answer
OSPF broadcast DR election considers eligible nonzero interface priority first, with router ID breaking ties. R4 has the highest eligible priority 100.
Incorrect Answers
This router has zero priority or an inferior priority to the winner and cannot be the elected DR here.
That explanation does not distinguish this option. “R2 (priority 6, router ID 10.255.0.253)” is an alternative action, but it does not by itself establish the outcome required in this case.
That explanation does not distinguish this option. “R3 (priority 7, router ID 10.255.0.153)” is an alternative action, but it does not by itself establish the outcome required in this case.