ANS-C01 Question 184
Single answerYour company is running a hybrid cloud architecture and uses AWS Transit Gateway to connect its on-premises network with multiple VPCs in AWS. The on-premises network is connected to AWS via a Direct Connect connection. Recently, your team noticed that traffic between the on-premises network and certain VPCs is experiencing higher latency than expected. Upon investigation, you find that the Transit Gateway is routing traffic through a different Availability Zone than expected. How can this issue be resolved?
- A
Enable Transit Gateway route table propagation to ensure proper routing.
- B
Configure appliance mode on the Transit Gateway to allow for direct routing.
- C
Create a Transit Gateway attachment in the same Availability Zone as the impacted VPCs.
- D
Associate each VPC attachment with a specific subnet in the desired Availability Zone.
Show answer and explanation
Correct answer: C
Explanation
AWS Transit Gateway routes traffic based on the shortest path, which may sometimes result in traffic being routed through a different Availability Zone than desired. By creating a Transit Gateway attachment in the same Availability Zone as the VPCs experiencing latency issues, you can ensure that traffic remains within the desired zone, reducing unnecessary cross-AZ latency.
- A. Incorrect.
Transit Gateway route table propagation allows dynamic propagation of routes but does not address the issue of routing through specific Availability Zones.
- B. Incorrect.
Appliance mode is used for specific use cases such as integrating with third-party appliances but does not resolve the issue of traffic being routed through an unintended Availability Zone.
- C. Correct.
Creating a Transit Gateway attachment in the same Availability Zone as the impacted VPCs ensures that traffic remains within that Availability Zone, reducing latency caused by cross-AZ routing.
- D. Incorrect.
Associating a VPC attachment with a specific subnet only dictates where the attachment is anchored but does not control the Transit Gateway's routing behavior across Availability Zones.