- A
Use Dedicated Interconnect to connect the VPCs.
Why wrong: Dedicated Interconnect is for connecting on-premises networks to GCP, not for VPC-to-VPC connectivity.
- B
Enable VPC Network Peering between vpc-a and vpc-b.
VPC Network Peering allows private RFC 1918 connectivity across two VPCs, regardless of project or region, as long as they are in the same organization or project.
- C
Set up Cloud VPN tunnels between the two VPCs.
Why wrong: Cloud VPN is used to connect on-premises networks to GCP, not for VPC-to-VPC within the same project. It requires public IPs and adds latency.
- D
Configure Cloud NAT to allow the VPCs to communicate through NAT.
Why wrong: Cloud NAT provides outbound internet access for instances without external IPs, not direct VPC-to-VPC communication.
Quick Answer
The answer is to enable VPC Network Peering between vpc-a and vpc-b, as this is the only native Google Cloud solution that allows two VPCs in the same project to communicate using internal private IP addresses without any external gateways or bandwidth constraints. VPC Network Peering directly connects the two networks at the routing layer, enabling all subnets in both VPCs to exchange traffic over Google’s internal backbone using RFC 1918 addresses, with no single point of failure and no need for VPN tunnels or NAT. On the Google Professional Cloud Network Engineer exam, this scenario tests your understanding of when to use peering versus Shared VPC or Cloud VPN—a common trap is assuming you need a VPN or a separate interconnect for same-project VPCs, but peering is simpler and fully private. Remember the memory tip: “Same project, same peering—no VPN needed for internal steering.”
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 wants to connect two VPC networks (vpc-a and vpc-b) that both reside in the same Google Cloud project. They need to ensure that all IP ranges in both VPCs can communicate using internal private IP addresses. Which solution should they implement?
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
Enable VPC Network Peering between vpc-a and vpc-b.
VPC Network Peering directly connects two VPCs within the same project using internal RFC 1918 IP addresses, with no bandwidth limitations and no single point of failure. It allows all subnets in both VPCs to communicate privately without requiring external connectivity, VPN tunnels, or NAT gateways.
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.
- ✗
Use Dedicated Interconnect to connect the VPCs.
Why it's wrong here
Dedicated Interconnect is for connecting on-premises networks to GCP, not for VPC-to-VPC connectivity.
- ✓
Enable VPC Network Peering between vpc-a and vpc-b.
Why this is correct
VPC Network Peering allows private RFC 1918 connectivity across two VPCs, regardless of project or region, as long as they are in the same organization or project.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Set up Cloud VPN tunnels between the two VPCs.
- ✗
Configure Cloud NAT to allow the VPCs to communicate through NAT.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Google Cloud often tests the misconception that VPN or Interconnect is required for VPC-to-VPC connectivity, but in Google Cloud, VPC Network Peering is the native, simpler solution for same-project or cross-project private communication.
Detailed technical explanation
How to think about this question
VPC Network Peering uses the Google Cloud internal infrastructure to exchange routes between the two VPCs, enabling direct communication without any intermediate gateway. It supports up to 25 peering connections per VPC and automatically propagates subnets (excluding those with overlapping CIDRs). A real-world scenario is connecting a shared services VPC (e.g., with Active Directory) to multiple application VPCs, where peering avoids the cost and complexity of VPN tunnels.
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
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.
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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 — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Enable VPC Network Peering between vpc-a and vpc-b. — VPC Network Peering directly connects two VPCs within the same project using internal RFC 1918 IP addresses, with no bandwidth limitations and no single point of failure. It allows all subnets in both VPCs to communicate privately without requiring external connectivity, VPN tunnels, or NAT gateways.
What should I do if I get this PCNE 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.
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Last reviewed: Jun 30, 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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