300-420 Question 16
Select 3An enterprise network consists of multiple branch offices connected to two central data centers using EIGRP as the routing protocol. The organization wants to ensure stability, scalability, and security in the routing design. Which of the following design decisions would best meet these requirements?
- A
Implement EIGRP summarization at the data center routers to reduce routing table size across the network.
- B
Enable EIGRP stub routing on branch office routers to limit unnecessary routing updates.
- C
Use the default EIGRP metric values without modification across all interfaces for simplicity in configuration.
- D
Authenticate EIGRP neighbor relationships using Message Digest 5 (MD5) or higher to prevent unauthorized devices from joining.
- E
Disable split horizon across all interfaces to allow bidirectional route advertisement.
Show answer and explanation
Correct answers: A, B, D
Explanation
To create a stable, secure, and scalable EIGRP routing design, it is essential to implement summarization, use stub routing where applicable, and secure neighbor relationships with authentication. Summarization improves scalability by reducing routing table size and the impact of route changes. Stub routing limits unnecessary routing updates, enhancing scalability and stability. Authentication ensures only authorized devices can participate, improving security. Using default metrics and disabling split horizon without proper design considerations can lead to suboptimal routing and instability.
- A. Correct.
Implementing EIGRP summarization reduces the size of routing tables and minimizes the impact of route flapping, enhancing stability and scalability. This is a recommended design practice.
- B. Correct.
Enabling EIGRP stub routing prevents branch routers from propagating unnecessary routing information to the network, improving scalability and reducing resource usage.
- C. Incorrect.
Using default EIGRP metric values without modification may lead to suboptimal routing in some cases. Adjusting metrics is often necessary to meet specific design requirements.
- D. Correct.
Authenticating EIGRP neighbor relationships improves security by ensuring only authorized devices can participate in the EIGRP domain.
- E. Incorrect.
Disabling split horizon across all interfaces can lead to routing loops and instability. Split horizon should only be disabled in specific scenarios, such as hub-and-spoke configurations with careful design.