300-420 Question 39
Select 3A large enterprise is designing a new BGP network to connect multiple branch offices. To optimize scalability, the design team decides to use route reflectors. Which of the following considerations must be accounted for when implementing route reflectors in this network?
- A
Clients of the route reflector do not need to establish full mesh iBGP sessions with each other.
- B
The route reflector can modify the BGP next-hop attribute when advertising routes to its clients.
- C
Route reflectors introduce the risk of routing loops, which can be mitigated using cluster IDs.
- D
All clients in a route reflector cluster must belong to the same autonomous system.
- E
Route reflectors eliminate the need for all devices in the network to use iBGP.
Show answer and explanation
Correct answers: A, C, D
Explanation
Route reflectors are designed to improve the scalability of iBGP networks by reducing the need for full mesh connectivity between iBGP peers. However, they come with specific considerations, such as the risk of routing loops, which are mitigated using cluster IDs. Additionally, all route reflector clients must be in the same autonomous system, as route reflectors operate within iBGP. While route reflectors reduce complexity, iBGP is still required for routing within the AS.
- A. Correct.
Correct: One of the primary advantages of using route reflectors is that clients do not need to establish full mesh iBGP sessions, which helps reduce configuration complexity and improves scalability.
- B. Incorrect.
Incorrect: Route reflectors do not modify the BGP next-hop attribute when advertising routes. The next-hop remains unchanged unless explicitly configured otherwise.
- C. Correct.
Correct: Route reflectors can introduce routing loops. To prevent this, cluster IDs are used to detect loops within the route reflector topology.
- D. Correct.
Correct: All clients in a route reflector configuration must belong to the same autonomous system (AS) because route reflectors are used within an iBGP environment.
- E. Incorrect.
Incorrect: While route reflectors reduce the need for a full mesh iBGP configuration, they do not eliminate the need for iBGP itself. iBGP is still required for internal routing within the AS.