Google PCA Manage and provision cloud infrastructure Practice Question
A company has two VPC networks in the same project: 'vpc-prod' and 'vpc-dev'. They want to allow communication between instances in both VPCs. What is the simplest method?
⚠ Common exam trap
Google Cloud often tests the misconception that firewall rules alone can enable inter-VPC communication, but candidates must remember that firewall rules are only effective after a connectivity mechanism (like peering or VPN) is in place.
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
✓
Create a VPC Network Peering connection between them
VPC Network Peering is the simplest method because it directly connects two VPCs using Google's internal infrastructure, allowing private RFC 1918 IP communication across the networks without requiring external gateways, VPN tunnels, or additional bandwidth costs. It requires no routes to be manually configured—Google automatically adds the necessary routes for each peered VPC's subnets—and only a single firewall rule to permit traffic between the instances.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Create a VPC Network Peering connection between them
Why this is correct
VPC Network Peering enables direct, private connectivity.
- ✗
Set up a Cloud VPN tunnel between the two VPCs
Why it's wrong here
Cloud VPN is primarily designed for establishing secure connectivity between Google Cloud VPCs and on-premises networks, or between VPCs in different projects or organisations. For two VPCs within the *same* project, Cloud VPN introduces unnecessary complexity and cost, as it routes traffic over external tunnels rather than leveraging Google's internal network infrastructure. This option is tempting because VPNs are a common method for connecting disparate networks, and it would be the correct choice for hybrid cloud connectivity or for securely linking VPCs across different projects where VPC Network Peering is not suitable.
- ✗
Configure a custom route in each VPC pointing to the other's subnet
Why it's wrong here
Routing alone does not create connectivity; you need a mechanism like peering or VPN.
- ✗
Add firewall rules allowing traffic between the VPCs
Why it's wrong here
Firewall rules cannot cross VPC boundaries without a connection.
Visual reference
Go deeper
Related to this question
Learn chapter
VPC Peering and Shared VPC
Key term
VPN
A VPN (Virtual Private Network) creates a secure, encrypted tunnel between your device and a remote server, protecting your data and hiding your online activity.
Key term
Bandwidth
Bandwidth is the maximum amount of data that can travel over a network connection in a given amount of time, usually measured in bits per second.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This PCA 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 PCA exam.