ANS-C01 Network Implementation Practice Question
A network engineer is troubleshooting high latency between two EC2 instances in the same VPC but in different Availability Zones. The instances are in the same security group and have proper rules. Which configuration is most likely causing the latency?
⚠ Common exam trap
Test-takers frequently assume all instances in the same VPC have identical latency regardless of AZ placement, overlooking the fundamental physical and network architecture differences between intra-AZ and inter-AZ communication.
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
✓
The instances are in different Availability Zones.
The primary cause of higher latency between EC2 instances in different Availability Zones is the physical distance and the additional network hops required to traverse the AZ boundary. Even within the same VPC, traffic between AZs must pass through AWS's regional network infrastructure, which introduces a baseline latency of 1-2 milliseconds, whereas instances in the same AZ can communicate with sub-millisecond latency. The question explicitly states the instances are in different AZs, making this the most likely source of the latency issue.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The instances are using jumbo frames.
Why it's wrong here
Jumbo frames help, not cause latency.
- ✗
The instances are in a cluster placement group.
Why it's wrong here
Cluster placement groups reduce latency.
- ✗
The instances have Enhanced Networking enabled.
Why it's wrong here
Enhanced Networking reduces latency.
- ✓
The instances are in different Availability Zones.
Why this is correct
Inter-AZ traffic has higher latency.
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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.