300-440 Question 189
Select 3A network engineer is configuring an EIGRP domain using IPv6 on a network with a large number of routers. To simplify the configuration, the engineer decides to use dynamic neighbor discovery instead of manually configuring neighbors. Which of the following conditions must be met for dynamic neighbor discovery to function correctly in this scenario?
- A
Routers must be on the same link-layer network.
- B
The EIGRP process must be configured with an IPv6 link-local address.
- C
The 'neighbor' command must be used in the EIGRP configuration.
- D
Routers must be configured with the same EIGRP AS number.
- E
IPv6 multicast group FF02::A must be enabled on all participating routers.
Show answer and explanation
Correct answers: A, D, E
Explanation
Dynamic neighbor discovery in EIGRP for IPv6 relies on multicast communication (FF02::A) and requires routers to be on the same link-layer network. Additionally, the EIGRP AS number must match on all routers to establish adjacencies. The use of the 'neighbor' command is specific to static neighbor configurations and is not required for dynamic discovery.
- A. Correct.
Correct: Dynamic neighbor discovery requires routers to be on the same link-layer network because it relies on multicast traffic for neighbor discovery.
- B. Incorrect.
Incorrect: While EIGRP uses IPv6 link-local addresses for communication, these addresses are automatically assigned and do not require manual configuration.
- C. Incorrect.
Incorrect: The 'neighbor' command is used for static neighbor configuration, not for dynamic neighbor discovery.
- D. Correct.
Correct: All routers within the same EIGRP domain must use the same AS number to form adjacencies.
- E. Correct.
Correct: IPv6 multicast group FF02::A is used by EIGRP for dynamic neighbor discovery and must be enabled on all routers participating in the EIGRP domain.