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.
A company needs to connect on-premises to GCP using Dedicated Interconnect with a 10 Gbps link, and they require high availability. They plan to use a single VLAN attachment. What is the best design?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "best"
Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Deploy two interconnects with one VLAN attachment each.
For high availability with Dedicated Interconnect, you need two separate physical connections (interconnects) to avoid a single point of failure. Each interconnect must have its own VLAN attachment and BGP session to ensure that if one link fails, traffic can still flow over the other. A single VLAN attachment cannot provide redundancy because it is tied to one physical interconnect.
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.
✓
Deploy two interconnects with one VLAN attachment each.
Why this is correct
This provides physical diversity and HA.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Deploy one interconnect with one VLAN attachment and a VPN as backup.
Why it's wrong here
While this provides some redundancy, the recommended approach is dual interconnects.
✗
Deploy one interconnect with one VLAN attachment and use static routing.
Why it's wrong here
Static routing is not recommended for HA and does not provide failover.
✗
Deploy two VLAN attachments on the same interconnect with separate BGP sessions.
Why it's wrong here
This does not provide physical redundancy; the interconnect is a single point of failure.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Google Cloud often tests the misconception that multiple VLAN attachments on the same physical interconnect provide high availability, but in reality, they share the same physical path and single point of failure.
Detailed technical explanation
How to think about this question
Dedicated Interconnect uses BGP for dynamic routing, which enables automatic failover between two separate interconnects via BGP path selection (e.g., MED, AS path). Each VLAN attachment is associated with a Cloud Router and a BGP session, and the two interconnects must terminate on different edge routers in the same or different metro locations to achieve true high availability. Google recommends using at least two interconnects with separate VLAN attachments to meet a 99.99% SLA.
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
An e-commerce site experiences heavy traffic on Black Friday and near-zero traffic during off-peak weeks. Rather than provisioning permanent large VMs, the team uses auto-scaling groups that add capacity automatically under load and reduce it overnight. Questions like this test whether you understand elasticity, availability zones, and cloud compute scaling patterns.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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: Deploy two interconnects with one VLAN attachment each. — For high availability with Dedicated Interconnect, you need two separate physical connections (interconnects) to avoid a single point of failure. Each interconnect must have its own VLAN attachment and BGP session to ensure that if one link fails, traffic can still flow over the other. A single VLAN attachment cannot provide redundancy because it is tied to one physical interconnect.
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.
Are there clue words in this question I should notice?
Yes — watch for: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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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.
Question Discussion
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