200-301 Question 342
Select 2You are configuring OSPF on a broadcast network with multiple routers. During the DR/BDR election process, which of the following factors determine the selection of the DR and BDR?
- A
The router with the highest OSPF priority
- B
The router with the lowest OSPF Router ID
- C
The first router to come online in the network
- D
The router with the highest IP address on its OSPF-enabled interface
- E
The router with the least number of established OSPF neighbors
Show answer and explanation
Correct answers: A, B
Explanation
In OSPF broadcast networks, the Designated Router (DR) and Backup Designated Router (BDR) are determined based on the OSPF priority first. If priorities are equal, the Router ID is used as a tie-breaker. The router with the highest priority becomes the DR, and the next highest becomes the BDR. The order of router startup, IP addresses on interfaces, or the number of OSPF neighbors does not influence this election process.
- A. Correct.
Correct. The DR is selected based on the highest OSPF priority. If multiple routers have the same priority, the Router ID is used as the tie-breaker.
- B. Correct.
Correct. If the OSPF priorities are the same, the router with the lowest Router ID is selected as the DR or BDR.
- C. Incorrect.
Incorrect. The order in which routers come online does not influence the DR/BDR election process.
- D. Incorrect.
Incorrect. While the Router ID is influenced by IP addresses, the election process does not directly depend on the highest IP address on an interface.
- E. Incorrect.
Incorrect. The number of OSPF neighbors a router has does not affect the DR/BDR election process.