Google PCA Manage and provision cloud infrastructure Practice Question
A company wants to minimize egress costs for data transferred between Compute Engine instances in the same region but different zones. What is the best practice?
⚠ Common exam trap
Many candidates confuse 'different zones' with 'different regions' and assume egress costs apply, or they mistakenly think that using external IPs or NAT is necessary for inter-instance communication, when in fact internal IPs within the same VPC and region are free and optimal.
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 internal IPs and ensure they are in the same VPC.
B is correct because data transfer between Compute Engine instances in the same region but different zones uses internal IP addresses within the same VPC, which incurs no egress costs. Google Cloud does not charge for traffic between instances using internal IPs within the same region, regardless of zone, as long as they are in the same VPC network. This is the most cost-effective approach for minimizing egress costs.
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 a VPN connection.
Why it's wrong here
VPN is for hybrid connectivity, not for reducing intra-region costs.
- ✓
Use internal IPs and ensure they are in the same VPC.
Why this is correct
Internal IP traffic within the same VPC and region is free.
- ✗
Use Cloud NAT.
Why it's wrong here
Cloud NAT provides outbound internet access for instances without external IP addresses; it does not change how Google bills inter-zone traffic within a region, which still incurs egress charges. Cloud NAT is correct when private instances need outbound internet connectivity without exposing them to inbound connections.
- ✗
Use external IPs for all instances.
Why it's wrong here
External IPs route inter-zone traffic through the public internet, incurring egress charges, whereas internal IPs keep same-region zone-to-zone traffic on Google's network. External IPs are tempting for simple connectivity, and would be correct for instances needing inbound access from outside the VPC.
Go deeper
Related to this question
Learn chapter
Security Best Practices and Compliance
Key term
VPC network
A Virtual Private Cloud (VPC) network is a logically isolated section of a public cloud provider's infrastructure where you can launch cloud resources in a virtual network that you define and control.
Key term
VPC
A Virtual Private Cloud (VPC) is a logically isolated section of a cloud provider's network where you can launch and manage resources like servers and databases with complete control over IP addressing, subnets, route tables, and security.
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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.