300-420 Question 10
Select 3A large enterprise network is implementing Intermediate System-to-Intermediate System (IS-IS) for its campus and data center environments. The network team wants to design a stable, secure, and scalable routing solution. Which two design considerations should be implemented to achieve this goal?
- A
Enable IS-IS authentication to protect routing updates from unauthorized sources.
- B
Use a single large IS-IS area to simplify route propagation and reduce complexity.
- C
Configure overload bit settings on specific routers to influence route selection during maintenance or startup.
- D
Disable IS-IS metric-based traffic engineering to avoid complexity in routing decisions.
- E
Implement route summarization between IS-IS areas to optimize the size of routing tables.
Show answer and explanation
Correct answers: A, C, E
Explanation
Designing a stable, secure, and scalable IS-IS routing solution involves key considerations such as ensuring security through authentication, optimizing scalability with techniques like route summarization, and enhancing stability by using features like the overload bit for route control during specific conditions. These practices collectively ensure the network operates efficiently and securely while accommodating growth.
- A. Correct.
Enabling IS-IS authentication ensures that only authorized devices can participate in the routing domain, improving network security.
- B. Incorrect.
Using a single large IS-IS area can lead to scalability challenges in large networks, as the routing tables and LSDB (Link State Database) grow significantly.
- C. Correct.
The overload bit can be used to manipulate route preference, preventing routers from being used for transit traffic during specific situations such as maintenance.
- D. Incorrect.
Disabling metric-based traffic engineering would reduce the flexibility of the IS-IS protocol in optimizing routing decisions, particularly in complex networks.
- E. Correct.
Route summarization reduces the size of routing tables, enhances scalability, and limits the propagation of unnecessary updates across IS-IS areas.