- A
Transitive peering is not supported; if Network A is peered with Network B and Network A is peered with Network C, Network B cannot communicate with Network C through Network A.
VPC peering is non-transitive; traffic must be directly peered.
- B
Peered networks can use globally distributed routing to communicate across regions without additional configuration.
Why wrong: Peered networks can communicate across regions only if subnets in both networks exist in the same region or proper routes are configured; no automatic global routing.
- C
Default routes (0.0.0.0/0) are automatically exported and imported between peered networks.
Why wrong: Default routes are not automatically exchanged; they must be explicitly configured for export/import.
- D
Firewall rules from one network are automatically applied to the peered network.
Why wrong: Firewall rules are not shared; each network maintains its own firewall policies.
- E
The subnet IP ranges of peered VPC networks must not overlap.
Overlapping subnets cause routing conflicts and are not allowed.
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. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.
Which TWO statements about VPC Network Peering are correct? (Choose TWO.)
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
Transitive peering is not supported; if Network A is peered with Network B and Network A is peered with Network C, Network B cannot communicate with Network C through Network A.
Option A is correct because VPC Network Peering is non-transitive by design. This means that if Network A is peered with both Network B and Network C, traffic cannot flow from Network B to Network C through Network A. Each peering connection is a direct, point-to-point link, and routing is not propagated across multiple peering hops. This behavior is enforced by the GCP networking stack to prevent complex and unintended routing topologies.
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.
- ✓
Transitive peering is not supported; if Network A is peered with Network B and Network A is peered with Network C, Network B cannot communicate with Network C through Network A.
Why this is correct
VPC peering is non-transitive; traffic must be directly peered.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Peered networks can use globally distributed routing to communicate across regions without additional configuration.
Why it's wrong here
Peered networks can communicate across regions only if subnets in both networks exist in the same region or proper routes are configured; no automatic global routing.
- ✗
Default routes (0.0.0.0/0) are automatically exported and imported between peered networks.
Why it's wrong here
Default routes are not automatically exchanged; they must be explicitly configured for export/import.
- ✗
Firewall rules from one network are automatically applied to the peered network.
Why it's wrong here
Firewall rules are not shared; each network maintains its own firewall policies.
- ✓
The subnet IP ranges of peered VPC networks must not overlap.
Why this is correct
Overlapping subnets cause routing conflicts and are not allowed.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Google Cloud often tests the misconception that VPC Network Peering supports transitive routing, similar to how traditional router-based networks work, but GCP explicitly disallows this to enforce network segmentation and prevent unintended traffic flows.
Detailed technical explanation
How to think about this question
Under the hood, VPC Network Peering uses the GCP Andromeda software-defined networking stack to establish a direct L3 connection between two VPC networks. The non-transitive behavior is enforced by the routing tables: each peering connection installs routes only for the directly peered network's subnets, and no route propagation occurs across multiple peering links. This design prevents routing loops and maintains network isolation, which is critical in multi-tenant or complex enterprise environments where you might have hub-and-spoke topologies requiring explicit VPN or intermediary appliances for transitive routing.
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: Transitive peering is not supported; if Network A is peered with Network B and Network A is peered with Network C, Network B cannot communicate with Network C through Network A. — Option A is correct because VPC Network Peering is non-transitive by design. This means that if Network A is peered with both Network B and Network C, traffic cannot flow from Network B to Network C through Network A. Each peering connection is a direct, point-to-point link, and routing is not propagated across multiple peering hops. This behavior is enforced by the GCP networking stack to prevent complex and unintended routing topologies.
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.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
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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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