- A
Enable Cloud NAT logging and analyze logs in Cloud Logging
Why wrong: Cloud NAT logs show connection attempts but not per-instance bandwidth usage.
- B
Export VPC Flow Logs to BigQuery and query by source instance
Correct: VPC Flow Logs contain instance metadata and can be aggregated in BigQuery to compute egress per instance.
- C
Use Firewall Insights to identify high-traffic instances
Why wrong: Firewall Insights focus on rule usage, not traffic volume.
- D
Use the Performance Dashboard to see bandwidth usage per region
Why wrong: Performance Dashboard shows latency and packet loss between regions, not per-instance bandwidth.
Question 337 of 982
PCNE Practice Question: Managing, Monitoring, and Optimising Network Operations
This PCNE practice question tests your understanding of managing, monitoring, and optimising network operations. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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.
An organization has a VPC with multiple subnets and Cloud NAT configured for outbound internet access. They need to analyze which instances are using the most egress bandwidth to optimize costs. Which approach is most effective?
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
✓
Export VPC Flow Logs to BigQuery and query by source instance
VPC Flow Logs exported to BigQuery allow detailed analysis of traffic patterns, including source IP, destination, and bytes transferred, enabling cost attribution.
Key principle: Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Enable Cloud NAT logging and analyze logs in Cloud Logging
Why it's wrong here
Cloud NAT logs show connection attempts but not per-instance bandwidth usage.
- ✓
Export VPC Flow Logs to BigQuery and query by source instance
Why this is correct
Correct: VPC Flow Logs contain instance metadata and can be aggregated in BigQuery to compute egress per instance.
Related concept
CIDR notation defines the prefix length.
- ✗
Use Firewall Insights to identify high-traffic instances
Why it's wrong here
Firewall Insights focus on rule usage, not traffic volume.
- ✗
Use the Performance Dashboard to see bandwidth usage per region
Why it's wrong here
Performance Dashboard shows latency and packet loss between regions, not per-instance bandwidth.
Common exam traps
Common exam trap: usable hosts are not the same as total addresses
Subnetting questions often tempt you into counting all addresses. In normal IPv4 subnets, the network and broadcast addresses are not usable host addresses.
Trap categories for this question
Command / output trap
Cloud NAT logs show connection attempts but not per-instance bandwidth usage.
Detailed technical explanation
How to think about this question
Subnetting questions test whether you can identify the network, broadcast address, usable range, mask and correct subnet. Slow down enough to calculate the block size correctly.
KKey Concepts to Remember
- CIDR notation defines the prefix length.
- Block size helps identify subnet boundaries.
- Network and broadcast addresses are not usable hosts in normal IPv4 subnets.
- The required host count determines the smallest suitable subnet.
TExam Day Tips
- Write the block size before choosing the subnet.
- Check whether the question asks for hosts, subnets or a specific address range.
- Do not confuse /24, /25, /26 and /27 host counts.
Key takeaway
Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
Real-world example
How this comes up in practice
A startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
Visual reference
What to study next
Got this wrong? Here's your next step.
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related PCNE subnetting questions on CIDR, address ranges, and subnet selection.
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Managing, Monitoring, and Optimising Network Operations — study guide chapter
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FAQ
Questions learners often ask
What does this PCNE question test?
Managing, Monitoring, and Optimising Network Operations — This question tests Managing, Monitoring, and Optimising Network Operations — CIDR notation defines the prefix length..
What is the correct answer to this question?
The correct answer is: Export VPC Flow Logs to BigQuery and query by source instance — VPC Flow Logs exported to BigQuery allow detailed analysis of traffic patterns, including source IP, destination, and bytes transferred, enabling cost attribution.
What should I do if I get this PCNE question wrong?
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related PCNE subnetting questions on CIDR, address ranges, and subnet selection.
What is the key concept behind this question?
CIDR notation defines the prefix length.
About these practice questions
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Last reviewed: Jul 4, 2026
This PCNE practice question is part of Courseiva's free Google Cloud 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 PCNE exam.
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