ANS-C01 Question 351
Select 2Your organization is deploying a highly available application across two AWS Regions. The application leverages VPC peering between the Regions for communication. During testing, you notice that some traffic is not being routed correctly. On investigation, you find that the issue is caused by route table limits being exceeded. What actions can you take to resolve this issue?
- A
Request a service quota increase for the route table entry limit through the AWS Support Center.
- B
Use AWS Transit Gateway to centralize routing and reduce the number of route table entries required.
- C
Create additional route tables within your VPC to distribute routes across multiple tables.
- D
Aggregate CIDR ranges in your route table to reduce the number of individual routes.
- E
Use Network Load Balancers (NLBs) to bypass the route table limits in VPC peering.
Show answer and explanation
Correct answers: B, D
Explanation
Route table entry limits are a common challenge in complex networking setups, such as when using VPC peering for inter-region communication. AWS Transit Gateway is a recommended solution to centralize and simplify routing, reducing the need for large numbers of route table entries. Additionally, aggregating CIDR ranges can help optimize the route table by reducing the number of individual routes required. These approaches ensure compliance with AWS limits while maintaining network functionality.
- A. Incorrect.
Route table entry limits are fixed and cannot be increased through a service quota request. AWS has predefined hard limits for route table entries.
- B. Correct.
Using AWS Transit Gateway can centralize routing and reduce the complexity and size of route tables, helping to avoid hitting route table limits.
- C. Incorrect.
While you can create multiple route tables in a VPC, this does not solve the issue of route table entry limits for a single table in VPC peering scenarios, as each subnet can only be associated with one route table.
- D. Correct.
Aggregating CIDR ranges can reduce the number of individual entries in a route table, helping to avoid exceeding the route table entry limit.
- E. Incorrect.
Network Load Balancers cannot bypass route table limits in VPC peering scenarios. They are used for load balancing but do not affect route table configurations.