Cisco Certified Network Associate (CCNA) Practice Exam

How can you influence OSPF designated router selection?

1. Change the area ID

2. Increase priority number or loopback interface number

3. Change the router ID

4. Reset the OSPF process

The correct answer is: Increase priority number or loopback interface number

The selection of a designated router (DR) in OSPF (Open Shortest Path First) is influenced primarily by the OSPF priority value configured on the routers in a broadcast network (such as Ethernet). Each OSPF-enabled router can be assigned a priority number, with higher values indicating a higher likelihood of being elected as the DR. When a network segment connects multiple OSPF routers, they engage in an election process, where the router with the highest priority is chosen as the DR. If two routers have the same priority, the router with the highest router ID (an identifier that is often the highest IP address on the router or a manually configured IP) will be selected. By increasing the priority number through configuration, you are directly influencing the outcome of the election process in favor of that router, thus enhancing its chances of becoming the designated router on that segment. Other choices, while they may seem relevant to changing OSPF behavior, do not directly impact the designated router election process in the same way. Changing the area ID will not affect DR selection within an area as it defines routing boundaries. The router ID, while used as a tiebreaker, does not influence priority directly; it only comes into play if