- A
Use Cloud VPN with HA VPN to connect all VPCs
Why wrong: HA VPN connects two networks, not three transitively.
- B
Use Network Connectivity Center with all VPCs as spokes
NCC hub-and-spoke provides transitive connectivity between spokes.
- C
Use a single shared VPC with subnets for all three networks
Why wrong: Shared VPC is for sharing subnets, not connecting separate VPCs.
- D
Establish VPC peering between each pair of VPCs (full mesh)
Why wrong: Full mesh peering is transitive but requires multiple connections; the question asks for a solution that does not require full mesh.
- E
Deploy a VPN appliance in one VPC and create VPN tunnels to the other two VPCs
A VPN appliance can provide transitive routing between VPCs.
Question 379 of 1,000
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.
An organization needs to connect three GCP VPCs (VPC-A, VPC-B, VPC-C) so that all VPCs can communicate with each other. They want a solution that is transitive and does not require full mesh peering. Which TWO approaches meet these requirements?
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
✓
Use Network Connectivity Center with all VPCs as spokes
Network Connectivity Center hub-and-spoke and a VPN appliance in a shared VPC can provide transitive routing. VPC peering is non-transitive and would require full mesh.
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.
- ✗
Use Cloud VPN with HA VPN to connect all VPCs
Why it's wrong here
HA VPN connects two networks, not three transitively.
- ✓
Use Network Connectivity Center with all VPCs as spokes
Why this is correct
NCC hub-and-spoke provides transitive connectivity between spokes.
Related concept
CIDR notation defines the prefix length.
- ✗
Use a single shared VPC with subnets for all three networks
Why it's wrong here
Shared VPC is for sharing subnets, not connecting separate VPCs.
- ✗
Establish VPC peering between each pair of VPCs (full mesh)
Why it's wrong here
Full mesh peering is transitive but requires multiple connections; the question asks for a solution that does not require full mesh.
- ✓
Deploy a VPN appliance in one VPC and create VPN tunnels to the other two VPCs
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.
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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Designing, Planning, and Prototyping a GCP Network — study guide chapter
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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: Use Network Connectivity Center with all VPCs as spokes — Network Connectivity Center hub-and-spoke and a VPN appliance in a shared VPC can provide transitive routing. VPC peering is non-transitive and would require full mesh.
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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