AWS Certified Advanced Networking – Specialty (ANS-C01) — Question 186
A company has a data center in the us-west-1 Region with a 10 Gbps AWS Direct Connect dedicated connection to a Direct Connect gateway. There are two private VIFs from the same data center location in us-west-1 that are attached to the same Direct Connect gateway.
VIF 1 advertises 172.16.0.0/16 with an AS_PATH attribute value of 65000. VIF 2 advertises 172.16.1.0/24 with an AS PATH attribute value of 65000 65000 65000.
How will AWS route traffic to the data center for traffic that has a destination address within the 172.16.1.0/24 network range?
Answer options
- A. AWS will route all traffic by using VIF 1.
- B. AWS will route all traffic by using VIF 2.
- C. AWS will use both VIFs for routing by using a round-robin policy.
- D. AWS will use flow control to balance the traffic between the two VIFs.
Correct answer: B
Explanation
AWS will route traffic to the 172.16.1.0/24 network using VIF 2 because it has a more specific route than VIF 1, which covers a broader range. Routes with a longer prefix length (like /24) are preferred over shorter ones (like /16), meaning VIF 2's advertisement will take precedence. The other options are incorrect as they suggest less specific or incorrect routing behavior.