AWS Certified Advanced Networking – Specialty (ANS-C00) — Question 16

You have a global corporate network with 153 individual IP prefixes in your internal routing table. You establish a private virtual interface over AWS Direct Connect to a VPC that has an Internet gateway (IGW). All instances in the VPC must be able to route to the Internet via an IGW and route to the global corporate network via the VGW.
How should you configure your on-premises BGP peer to meet these requirements?

Answer options

• A. Configure AS-Prepending on your BGP session
• B. Summarize your prefix announcement to less than 100
• C. Announce a default route to the VPC over the BGP session
• D. Enable route propagation on the VPC route table

Correct answer: B

Explanation

The correct answer is B, as summarizing the prefix announcement to less than 100 allows for efficient routing and meets the requirement for connectivity without overwhelming the routing table. Option A is incorrect as AS-Prepending is used for influencing route selection rather than fulfilling the specific routing requirement. Option C is not suitable because announcing a default route may not provide the necessary granularity for routing to specific prefixes. Option D is irrelevant since enabling route propagation does not address the need to summarize the prefixes.