300-415 Question 152
Single answerYou are deploying Cisco SD-WAN in a hybrid network environment where both MPLS and Internet circuits are used. You need to configure BGP for route advertisement between the SD-WAN fabric and the MPLS provider. During the configuration, you must ensure that only specific prefixes are advertised to the MPLS provider to maintain control over routing policies. Which feature or configuration step should be implemented to achieve this?
- A
Use BGP route filtering with prefix lists on the SD-WAN edge router.
- B
Enable BGP route dampening to control unstable routes advertised to the MPLS provider.
- C
Use OSPF instead of BGP for dynamic routing to the MPLS provider.
- D
Configure MPLS provider to advertise only default routes to the SD-WAN fabric.
Show answer and explanation
Correct answer: A
Explanation
In a hybrid SD-WAN environment, BGP route filtering using prefix lists is a best practice to control which prefixes are advertised to external providers, such as MPLS. This ensures that only desired routes are shared, maintaining proper routing policies and preventing the unintentional advertisement of internal routes. Other options either do not address the requirement or are unrelated to the scenario.
- A. Correct.
Using BGP route filtering with prefix lists allows you to control which prefixes are advertised to the MPLS provider. This is the correct approach for maintaining routing policy control in this scenario.
- B. Incorrect.
BGP route dampening is used to suppress unstable routes and is not relevant to controlling which prefixes are advertised to the MPLS provider.
- C. Incorrect.
Switching to OSPF would not address the need to control prefix advertisement. BGP is the appropriate protocol for such scenarios in hybrid environments.
- D. Incorrect.
Configuring the MPLS provider to advertise only default routes to the SD-WAN fabric does not address the requirement to control the prefixes advertised from the SD-WAN fabric to the MPLS provider.