The answer is to launch the instances in a Cluster Placement Group. This is the correct choice because a cluster placement group 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, which is essential for tightly coupled, latency-sensitive applications. On the AWS Certified Advanced Networking Specialty ANS-C01 exam, this concept tests your understanding of placement group types and their network performance characteristics; a common trap is confusing a spread or partition placement group, which prioritize fault tolerance over low latency. For low latency EC2 instances in a cluster placement group, remember that all instances must be in the same AZ and launched into the group at the same time to benefit from the dedicated 10 Gbps or 100 Gbps per-flow bandwidth. Memory tip: think “Cluster = Clustered in one AZ for low latency, like a tightly packed cluster of servers.”
ANS-C01 Network Design Practice Question
This ANS-C01 practice question tests your understanding of network design. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
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?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Launch the instances in a Cluster Placement Group.
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.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Launch the instances in a Cluster Placement Group.
Why this is correct
Cluster Placement Groups provide low-latency, high-throughput networking.
Related concept
Read the scenario before looking for a memorised answer.
✗
Launch the instances in a Spread Placement Group.
Why it's wrong here
Spread Placement Groups are for fault isolation, not performance.
✗
Launch the instances as larger instance types with enhanced networking.
Why it's wrong here
While enhanced networking helps, placement is key for low latency.
✗
Launch the instances in different Availability Zones.
Why it's wrong here
Cross-AZ traffic introduces higher latency.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse 'enhanced networking' (Option C) as a standalone solution for low latency, overlooking that placement group optimization is required to achieve the lowest possible latency and highest throughput, even with enhanced networking enabled.
Detailed technical explanation
How to think about this question
Cluster Placement Groups use a fully non-blocking, high-bandwidth network fabric (often leveraging AWS's Elastic Network Adapter and SR-IOV) to achieve single-digit microsecond latency and up to 100 Gbps throughput between instances. Under the hood, AWS reserves a dedicated, low-latency path within a single Availability Zone, but this design has a capacity limitation: if the placement group's capacity is exhausted, new instance launches may fail with an 'InsufficientInstanceCapacity' error, requiring careful planning for large clusters.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
An e-commerce site experiences heavy traffic on Black Friday and near-zero traffic during off-peak weeks. Rather than provisioning permanent large VMs, the team uses auto-scaling groups that add capacity automatically under load and reduce it overnight. Questions like this test whether you understand elasticity, availability zones, and cloud compute scaling patterns.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Network Design — This question tests Network Design — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Launch the instances in a Cluster Placement Group. — 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.
What should I do if I get this ANS-C01 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
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 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.)
medium
A.Attach an internet gateway to the VPC and route traffic through it.
✓ B.Enable enhanced networking (ENA) on the EC2 instances.
C.Use a VPN connection to route traffic between instances.
D.Use a spread placement group for the EC2 instances.
✓ E.Place the EC2 instances in a cluster placement group.
Why B: Option B is correct because 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.
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: Option B is correct because 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.
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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.
Question Discussion
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