350-401 Question 146
Select 2You are configuring OSPFv2 in a network with multiple normal areas. The network requires area summarization to reduce the size of the routing table and filtering to prevent specific routes from being advertised to a certain area. Additionally, some interfaces connecting internal routers to end devices should not send OSPF Hello packets. Which of the following configurations should you implement to meet the requirements?
- A
Configure area range on the ABR for summarization between areas.
- B
Apply a distribute-list on the ABR to filter routes between areas.
- C
Set the 'passive-interface' command on interfaces connected to end devices.
- D
Use a network type of 'broadcast' on all point-to-point links in the network.
Show answer and explanation
Correct answers: A, C
Explanation
To meet the requirements, you must summarize routes between OSPF areas and prevent unnecessary OSPF Hello packets on certain interfaces. The 'area range' command enables summarization on the ABR, helping reduce routing table size. The 'passive-interface' command is used to suppress OSPF Hello packets on interfaces where OSPF neighbors are not expected, such as interfaces connected to end devices. Distribute-lists are not applicable for OSPF route filtering between areas, and the correct network type for point-to-point links is 'point-to-point,' not 'broadcast.'
- A. Correct.
Correct: The 'area range' command on the ABR is used for summarization, which reduces routing table size by advertising a single summary route instead of multiple specific routes.
- B. Incorrect.
Incorrect: Distribute-lists are not used for filtering between OSPF areas. Instead, route filtering is achieved using 'area X filter-list' or 'prefix-list' applied at the ABR.
- C. Correct.
Correct: The 'passive-interface' command prevents OSPF Hello packets from being sent on interfaces where no neighbors are expected, such as interfaces connected to end devices.
- D. Incorrect.
Incorrect: A 'broadcast' network type is not optimal for point-to-point links. Instead, point-to-point links should use the 'point-to-point' network type, which simplifies OSPF operation by assuming a direct connection between two routers.