300-440 Question 102
Select 3A network engineer is configuring OSPF in a network with multiple Frame Relay links. Some links are point-to-point, while others are multipoint. The engineer needs to ensure OSPF forms adjacencies correctly and that LSAs are exchanged efficiently. Which OSPF network types should the engineer configure on these Frame Relay links to achieve the desired behavior?
- A
Point-to-Point
- B
Broadcast
- C
Non-Broadcast
- D
Point-to-Multipoint
Show answer and explanation
Correct answers: A, C, D
Explanation
When configuring OSPF over Frame Relay, the network type must match the topology of the link. Point-to-Point is used for individual subinterfaces, while Non-Broadcast and Point-to-Multipoint are used for multipoint configurations depending on whether manual neighbor configuration is desired. Broadcast is not typically used for Frame Relay.
- A. Correct.
Point-to-Point is appropriate for Frame Relay links configured as point-to-point subinterfaces, as it allows OSPF to form adjacencies directly between two devices without the need for DR/BDR elections.
- B. Incorrect.
Broadcast is generally used for Ethernet networks or similar media where all devices can communicate directly, but it is not suitable for Frame Relay unless explicitly emulated, which is rare.
- C. Correct.
Non-Broadcast is suitable for Frame Relay networks that do not support broadcast capabilities. OSPF in this mode requires manual neighbor configuration but can handle multiple devices on the same link.
- D. Correct.
Point-to-Multipoint is appropriate for Frame Relay networks with multiple endpoints where broadcast capability is not available. It is simpler to configure than Non-Broadcast and does not require manual neighbor configuration.