Q37 — AWS ANS-C01 Ch.1

Question 37 of 100 | ← Chapter 1

A company has a 2 Gbps AWS Direct Connect hosted connection from the company’s office to a VPC in the ap-southeast-2 Region. A network engineer adds a 5 Gbps Direct Connect hosted connection from a different Direct Connect location in the same Region. The hosted connections are connected to different routers from the office with an iBGP session running in between the routers. The network engineer wants to ensure that the VPC uses the 5 Gbps hosted connection to route traffic to the office. Failover to the 2 Gbps hosted connection must occur when the 5 Gbps hosted connection is down. Which solution will meet these requirements?

• A. Configure an outbound BGP policy from the router that is connected to the 2 Gbps connection. Advertise routes with a longer AS_PATH attribute to AWS. ✓
• B. Advertise a longer prefix route from the router that is connected to the 2 Gbps connection.
• C. Advertise a less specific route from the router that is connected to the 5 Gbps connection.
• D. Configure an outbound BGP policy from the router that is connected to the 5 Gbps connection. Advertise routes with a longer AS_PATH attribute to AWS.

Correct Answer: A. Configure an outbound BGP policy from the router that is connected to the 2 Gbps connection. Advertise routes with a longer AS_PATH attribute to AWS.

Explanation

在BGP（边界网关协议）中，AS_PATH（自治系统路径）长度是决定路由选择优先级的一个重要因素。较短的AS_PATH通常意味着更优选的路由。为了确保VPC优先使用5Gbps的连接，而仅在5Gbps连接故障时切换到2Gbps连接，应配置从连接到2Gbps连接的路由器上发出的BGP出站策略，以将路由与更长的AS_PATH属性通告给AWS。这样，AWS在路由决策时会优先选择AS_PATH较短的路由，即5Gbps连接。因此，正确答案是A。 查看全部