ANS-C01 practice question 3 of 35

Your company runs an application for the US market in the us-east-1 AWS region. This application uses proprietary TCP and UDP protocols on Amazon…

Your company runs an application for the US market in the us-east-1 AWS region. This application uses proprietary TCP and UDP protocols on Amazon Elastic Compute Cloud (EC2) instances. End users run a real-time, front-end application on their local PCs. This front-end application knows the DNS hostname of the service. You must prepare the system for global expansion. The end users must access the application with lowest latency. How should you use AWS services to meet these requirements?

Answer options

A: Register the IP addresses of the service hosts as “A” records with latency-based routing policy in Amazon Route 53, and set a Route 53 health check for these hosts.

B: Set the Elastic Load Balancing (ELB) load balancer in front of the hosts of the service, and register the ELB name of the main service host as an ALIAS record with a latency-based routing policy in Route 53. Correct answer

C: Set Amazon CloudFront in front of the host of the service, and register the CloudFront name of the main service as an ALIAS record in Route 53.

D: Set the Amazon API gateway in front of the service, and register the API gateway name of the main service as an ALIAS record in Route 53.

Correct Answer:

B. Set the Elastic Load Balancing (ELB) load balancer in front of the hosts of the service, and register the ELB name of the main service host as an ALIAS record with a latency-based routing policy in Route 53.

Explanation

Deploy a regional Network Load Balancer (or Classic/NLB) in front of the EC2 fleet in every region you expand to. Create a Route 53 ALIAS record for each load balancer and apply Latency-Based Routing with health checks. Users resolve the single service hostname to the load balancer in the region that offers the lowest measured RTT, ensuring minimal latency for proprietary TCP/UDP traffic without protocol conversion.

Why Incorrect

A. Registering instance IPs is brittle (IP changes, scaling) and lacks health-check integration with instance replacement.
C. CloudFront only proxies HTTP/HTTPS and cannot pass arbitrary TCP/UDP protocols.
D. API Gateway supports only HTTP/WebSocket APIs, not custom TCP/UDP.

References

1. Amazon Route 53 Developer Guide – “Latency-based routing” & “Choosing between A and ALIAS records”; supports ELB alias targets (https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/routing-policy.html#routing-policy-latency).

2. Elastic Load Balancing User Guide – “Network Load Balancers support TCP and UDP traffic” (Section: Features).

3. CloudFront Developer Guide – “Supported HTTP methods and protocols” (HTTP/HTTPS only).

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