ANS-C01 Question 336
Select 3You are managing a hybrid network architecture for a company that has an on-premises data center connected to AWS using AWS Direct Connect. The on-premises network communicates with an application hosted in multiple VPCs through a Transit Gateway. Recently, users reported intermittent connectivity issues when accessing the application. After investigating, you discovered that certain traffic is being dropped due to asymmetric routing. How can you resolve this issue while ensuring high availability and fault tolerance?
- A
Enable Equal Cost Multi-Path (ECMP) routing on the Transit Gateway.
- B
Ensure the Direct Connect gateway is configured for static routing only.
- C
Use Border Gateway Protocol (BGP) to advertise the same routes from multiple on-premises routers to AWS.
- D
Deploy additional Transit Gateways in each VPC to handle traffic more efficiently.
- E
Use Transit Gateway Route Tables to control and simplify traffic flow.
Show answer and explanation
Correct answers: A, C, E
Explanation
Asymmetric routing occurs when traffic takes different paths for inbound and outbound communication, leading to packet drops. Enabling ECMP on the Transit Gateway allows traffic to be distributed across multiple paths, reducing the chance of asymmetry. Using BGP ensures dynamic routing and failover, which further resolves asymmetry issues. Additionally, Transit Gateway Route Tables help efficiently control traffic flow and routing policies, ensuring proper traffic management in a hybrid architecture.
- A. Correct.
Enabling ECMP on the Transit Gateway allows for load balancing over multiple paths, which can reduce the likelihood of asymmetric routing issues. This is a key step in resolving the problem.
- B. Incorrect.
Static routing does not provide the dynamic failover and route optimization necessary to handle asymmetric routing. BGP is preferred in this scenario.
- C. Correct.
Using BGP to advertise the same routes from multiple on-premises routers ensures redundancy and allows AWS to dynamically choose the optimal path, mitigating asymmetric routing problems.
- D. Incorrect.
Deploying additional Transit Gateways is unnecessary. A single Transit Gateway can handle traffic for multiple VPCs effectively if configured correctly.
- E. Correct.
Transit Gateway Route Tables are essential for controlling how traffic flows between VPCs and on-premises networks. Proper route table configuration can prevent asymmetric routing and simplify traffic management.