ANS-C01 Network Design Practice Question
A company is designing a network for a critical application that requires low-latency communication between EC2 instances in the same AWS Region. They want to maximize network throughput and minimize latency. Which TWO design choices should they make? (Choose two.)
⚠ Common exam trap
AWS often tests the misconception that spread placement groups improve network performance, when in fact they are designed for high availability and fault tolerance, not low latency or high throughput.
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
✓
Enable enhanced networking (ENA) on the EC2 instances.
Enabling Enhanced Networking (ENA) on EC2 instances provides higher bandwidth, higher packet-per-second (PPS) performance, and consistently lower inter-instance latencies by using a modern network interface driver that offloads network processing to dedicated hardware. This is essential for critical applications requiring maximum throughput and minimal latency within the same AWS Region.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Attach an internet gateway to the VPC and route traffic through it.
Why it's wrong here
Internet gateways are for internet access, not for internal communication, and add latency.
- ✓
Enable enhanced networking (ENA) on the EC2 instances.
Why this is correct
Enhanced networking provides higher bandwidth and lower latency.
- ✗
Use a VPN connection to route traffic between instances.
Why it's wrong here
VPN connections add encryption overhead and latency.
- ✗
Use a spread placement group for the EC2 instances.
Why it's wrong here
Spread placement groups are designed to reduce the risk of simultaneous failures, not to optimize network performance.
- ✓
Place the EC2 instances in a cluster placement group.
Why this is correct
Cluster placement groups provide low-latency, high-throughput network performance between instances.
Go deeper
Related to this question
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Same concept, more angles
2 more ways 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 designing a network for a critical application that requires low latency and high throughput between EC2 instances in the same AWS Region. Which network design should the company use?
medium- ✓ A.Launch the instances in a Cluster Placement Group.
- B.Launch the instances in a Spread Placement Group.
- C.Launch the instances as larger instance types with enhanced networking.
- D.Launch the instances in different Availability Zones.
Why A: A Cluster Placement Group is the correct choice because it provides the lowest possible latency and highest throughput between EC2 instances by placing them in a single Availability Zone with non-blocking, high-bandwidth networking. This design is ideal for tightly coupled, high-performance computing (HPC) or latency-sensitive applications that require consistent, low-latency communication within the same AWS Region.
Variation 2. A company is designing a network for a critical application that requires low latency between EC2 instances. The instances are in the same AWS Region but different Availability Zones. Which configuration will provide the lowest latency?
hard- A.Use an Application Load Balancer to distribute traffic
- ✓ B.Launch instances in the same placement group within a single Availability Zone
- C.Use Direct Connect to connect the VPCs
- D.Use VPC peering to connect the VPCs
Why B: Placing EC2 instances within the same placement group in a single Availability Zone ensures they are in close physical proximity, often on the same rack or within the same cluster, which minimizes network hops and achieves the lowest possible latency (typically under 1 ms). This configuration is specifically designed for low-latency, high-throughput workloads like HPC or real-time data processing.
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.