ANS-C01 Network Design Practice Question
A company is deploying a critical application across multiple Availability Zones in a single AWS Region. They need a network design that provides the lowest possible latency between application tiers and supports automatic failover if an AZ becomes unavailable. Which design meets these requirements?
⚠ Common exam trap
Many exam-takers assume a single load balancer across all AZs is sufficient for low latency, but they overlook that cross-AZ traffic adds latency and that per-AZ NLBs with cross-zone load balancing disabled are required to keep traffic local.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Deploy an internal NLB per Availability Zone, with each NLB only registering targets in its own AZ, and an internet-facing Application Load Balancer (ALB) with targets in all AZs
Deploying an internal NLB per Availability Zone ensures cross-zone traffic is minimized, reducing latency between application tiers, while the internet-facing ALB provides automatic failover by distributing incoming traffic across healthy targets in all AZs. The NLB's per-AZ design keeps traffic within the same AZ for internal communication, and the ALB's health checks enable automatic rerouting if an AZ becomes unavailable.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Use Amazon Route 53 weighted routing to distribute traffic to each AZ
Why it's wrong here
Weighted routing does not provide automatic failover; health checks can be configured but it's not as seamless as a load balancer.
- ✓
Deploy an internal NLB per Availability Zone, with each NLB only registering targets in its own AZ, and an internet-facing Application Load Balancer (ALB) with targets in all AZs
Why this is correct
This keeps traffic within the AZ for lowest latency, and the ALB provides failover across AZs.
- ✗
Use a single internal Classic Load Balancer across all AZs
Why it's wrong here
Classic Load Balancer does not support cross-zone load balancing disabling and is not recommended for modern architectures.
- ✗
Deploy an internal Network Load Balancer (NLB) in a single AZ and route traffic from other AZs through it
Why it's wrong here
This creates a single point of failure and adds cross-AZ latency.
Go deeper
Related to this question
About these practice questions
Courseiva writes every ANS-C01 question from scratch — 1,621 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
Same concept, more angles
1 more way this is tested on ANS-C01
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company is deploying a critical application across multiple Availability Zones (AZs) in a single AWS region. The application requires a highly available network layer that can automatically detect and reroute traffic away from failed endpoints. Which AWS service should be used to meet this requirement?
medium- ✓ A.Network Load Balancer (NLB)
- B.AWS Global Accelerator
- C.Application Load Balancer (ALB)
- D.NAT gateway
Why A: A Network Load Balancer (NLB) operates at Layer 4 (TCP/UDP) and is designed to handle millions of requests per second with extremely low latency. It performs health checks on targets (e.g., EC2 instances) in each Availability Zone and automatically reroutes traffic away from unhealthy endpoints, providing the required high availability and automatic failover across AZs.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This ANS-C01 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the ANS-C01 exam.