Which architecture provides global HTTP low latency and sub-minute failover?

ANS-C01 By islever Editorial Last updated

Short answer

B Configure an Application Load Balancer (ALB) for the application in each environment in the new AWS Regions. Create an AWS Global Accelerator accelerator that has endpoint groups that point to the ALBs in each Region.

Question

An online retail company is running a web application in the us-wast-2 Region and serves consumers in the United States. The company plans to expand across several countries in Europe and wants to provide low latency for all its users. The application needs to identify the users’ IP addresses and provide localized content based on the users’ geographic location. The application uses HTTP GET and POST methods for its functionality. The company also needs to develop a failover mechanism that works for GET and POST methods and is based on health checks. The failover must occur in less than 1 minute for all clients. Which solution will meet these requirements?
  1. Configure a Network Load Balancer (NLB) for the application in each environment in the new AWS Regions. Create an AWS Global Accelerator accelerator that has endpoint groups that point to the NLBs in each Region.
  2. Configure an Application Load Balancer (ALB) for the application in each environment in the new AWS Regions. Create an AWS Global Accelerator accelerator that has endpoint groups that point to the ALBs in each Region. Correct Answer
  3. Configure an Application Load Balancer (ALB) for the application in each environment in the new AWS Regions. Create Amazon Route 53 public hosted zones that have failover routing policies.
  4. Configure a Network Load Balancer (NLB) for the application in each environment in the new AWS Regions. Create an Amazon CloudFront distribution. Configure an origin group with origin failover options.

Key Takeaways

This question tests whether you understand that ALB is a Layer 7 HTTP load balancer suited for GET/POST and X-Forwarded-For client IP handling, and that Global Accelerator delivers sub-minute failover through health-checked anycast endpoints rather than DNS TTL propagation.

For a global HTTP web app that must see client IPs, serve localized content, and fail over in under a minute, the best solution is an Application Load Balancer in each Region fronted by AWS Global Accelerator. The community strongly supports B, mainly because Global Accelerator uses anycast routing with fast health-check-based failover, while DNS-based failover can be delayed by client caching.

Common mistake: Many candidates choose C (Route 53 failover) or D (CloudFront origin failover). They see health checks in C and geographic content capabilities in D, but they miss that Route 53 failover depends on DNS TTLs and resolver caching, which cannot guarantee failover for all clients in under 1 minute, and that CloudFront origin failover is not primarily driven by configured health checks.

Expert Analysis

Correct answer: B

Option B correctly combines Application Load Balancers (ALBs) in each Region with an AWS Global Accelerator accelerator. The application is an HTTP application that uses GET and POST methods, so a Layer 7 load balancer is appropriate. ALB understands HTTP methods, supports path/host routing, and preserves the client IP via the X-Forwarded-For header. This allows the application to identify users' IP addresses and return localized content.

Why Global Accelerator is key

AWS Global Accelerator provides static anycast IP addresses and routes traffic over the AWS global network to the optimal endpoint. It continuously performs health checks on endpoint groups and can automatically reroute traffic to a healthy Region in seconds. Because clients connect to the same anycast IP, failover is transparent and does not depend on DNS caching or TTL expiration. This satisfies the requirement that failover must occur in less than 1 minute for all clients.

Why A is incorrect

Option A uses Network Load Balancers (NLBs). NLBs operate at Layer 4 and do not examine HTTP methods or headers. While an NLB can preserve client IP when paired with Global Accelerator, the ALB is the better choice for an HTTP application that needs GET/POST awareness, path-based routing, and HTTP health checks. NLB is more suited to TCP/UDP and ultra-high-performance traffic.

Why C is incorrect

Option C uses Route 53 failover routing with ALBs. Route 53 supports health-check-based failover, but it relies on DNS resolution. Even with a short TTL, clients and recursive resolvers may cache the old DNS response for longer than the desired failover time. DNS propagation and caching make it impossible to guarantee failover for all clients in under 1 minute. This is a common trap because Route 53 is a well-known global DNS service, but it is not the best tool for sub-minute, all-client failover.

Why D is incorrect

Option D combines CloudFront with an NLB and an origin group. CloudFront can serve dynamic HTTP content and supports localized content using headers such as CloudFront-Viewer-Country or Lambda@Edge. However, origin groups with origin failover are triggered when the primary origin returns certain error status codes (for example, 5xx), not necessarily by a health check. This behavior can be slower and less deterministic than Global Accelerator health-check-based failover. Also, using an NLB as the CloudFront origin does not provide the same Layer 7 HTTP features that an ALB would.

Community insight

One community comment correctly notes: "ALB: Handles HTTP-specific features like identifying user IPs and routing based on geolocation. Global Accelerator: Provides low-latency global routing and fast failover (less than 1 minute) with health checks." Another commenter explains that Route 53 might not meet the sub-minute requirement due to DNS propagation delays, and CloudFront is "more suited for static content, not necessarily for dynamic applications requiring HTTP GET and POST failover." These observations align with the official AWS recommended architecture for global HTTP workloads.

Official Reference

These links open the official vendor documentation in a new tab.

Exam Strategy

First identify whether the application requires HTTP-specific features; if yes, remove NLB-only answers. Then compare DNS-based failover with anycast-based failover and remember that a strict 'less than 1 minute for all clients' requirement eliminates Route 53 failover routing. Global Accelerator and ALB is the standard pairing for global HTTP workloads with fast failover.

Community Votes

B
62%
C
23%
D
15%

62% of anonymous learners picked answer B. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 9 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.

From public community threads 9

  1. VerRi 👍 4 Answered B
    HTTP req, A&D out. Global Accelerator is closer to the user; it can react faster than Route 53.
  2. luisgu 👍 3 Answered B
    Option A: While NLBs are performant, they are better suited for TCP rather than HTTP/HTTPS traffic. Option C: Route 53 might not meet the sub-minute failover requirement due to DNS propagation delays. Option D: CloudFront is more suited for static content, not necessarily for dynamic applications requiring HTTP GET and POST failover. Option B : ALB: Specifically designed for HTTP/HTTPS traffic and provides features like path-based routing and host-based routing. AWS Global Accelerator: Ensures low latency by routing traffic to the optimal region and provides quick failover mechanisms with health checks.
  3. 46f094c 👍 2 Answered D
    the only option that could handle "provide localized content based on the users’ geographic location". For POST using a lamda@edge.
  4. AzureDP900 👍 1 Answered B
    B is right In this case, since the application uses HTTP GET and POST methods, an ALB might be more suitable due to its support for more advanced request processing features like path-based routing and Lambda functions for custom processing.
  5. woorkim 👍 1
    B is correct! ALB: Handles HTTP-specific features like identifying user IPs and routing based on geolocation. Global Accelerator: Provides low-latency global routing and fast failover (less than 1 minute) with health checks.
Show 4 more comments
  1. AlirezaNetWorld 👍 2
    B is the correct answer
  2. aragon_saa 👍 2 Answered C
    Answer is C
  3. Nel07 👍 1
    Answer is B
  4. cas_tori 👍 1 Answered C
    this is C

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