- A
Peering succeeds, and only non-overlapping subnets are used
Why wrong: All subnets are overlapping; peering cannot be established.
- B
Peering succeeds, and routes are exchanged, but traffic may be unpredictable
Why wrong: Peering will fail due to overlapping subnets.
- C
Peering fails because subnets overlap
Overlapping IP ranges prevent VPC peering from being established.
- D
Peering succeeds, but routes are not exchanged
Why wrong: Peering will fail due to overlapping subnets.
Question 828 of 982
PCNE Practice Question: Designing, Planning, and Prototyping a GCP Network
This PCNE practice question tests your understanding of designing, planning, and prototyping a gcp network. 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 has two VPC networks in the same project: VPC-A (10.0.0.0/16) and VPC-B (10.0.0.0/16). They want to establish VPC Network Peering between them. What is the outcome?
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
✓
Peering fails because subnets overlap
VPC Network Peering requires that the subnets in the two VPCs do not overlap. Since both VPCs use the same CIDR block (10.0.0.0/16), peering will fail due to subnet overlap.
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.
- ✗
Peering succeeds, and only non-overlapping subnets are used
Why it's wrong here
All subnets are overlapping; peering cannot be established.
- ✗
Peering succeeds, and routes are exchanged, but traffic may be unpredictable
Why it's wrong here
Peering will fail due to overlapping subnets.
- ✓
Peering fails because subnets overlap
Why this is correct
Overlapping IP ranges prevent VPC peering from being established.
Related concept
CIDR notation defines the prefix length.
- ✗
Peering succeeds, but routes are not exchanged
Why it's wrong here
Peering will fail due to overlapping subnets.
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.
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 healthcare organisation deploys an application with a public-facing web tier and a private database tier. The database subnet has no public IP and only accepts connections from the web tier's security group. Questions like this test whether you can design cloud network isolation using VNets/VPCs, subnets, and security group rules.
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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FAQ
Questions learners often ask
What does this PCNE question test?
Designing, Planning, and Prototyping a GCP Network — This question tests Designing, Planning, and Prototyping a GCP Network — CIDR notation defines the prefix length..
What is the correct answer to this question?
The correct answer is: Peering fails because subnets overlap — VPC Network Peering requires that the subnets in the two VPCs do not overlap. Since both VPCs use the same CIDR block (10.0.0.0/16), peering will fail due to subnet overlap.
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.
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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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