GCP Networking Essentials: The Backbone of Your PCA Exam
If you ask any PCA candidate what the hardest part of the exam is, 8 out of 10 will say Networking. It's not just about knowing names; it's about understanding how traffic flows in a complex, global environment. Let's simplify it.
The Virtual Private Cloud (VPC): More Than a Network
On GCP, a VPC is global. This is a massive distinction from other clouds. You can have a single VPC with subnets in every continent. For the exam, remember:
- Global Scope: Makes multi-regional deployments easier.
- Dynamic Routing: Always use Cloud Router for hybrid setups.
- Private Google Access: Let your VMs reach Google APIs without a public IP.
Connecting VPCs: Peering vs. Shared VPC
Google loves asking when to use which. Here's a quick cheat sheet:
Shared VPC
Used for **Centralized Administration**. One host project controls the network, and service projects use the subnets. Best for large organizations with a central "Network Team."
VPC Network Peering
Used for **Decentralized Administration**. Two VPCs connect as equals. There is no central host. Great for connecting different companies or autonomous business units.
Load Balancing: Choosing the Right One
The exam will give you a scenario and ask for the "best" load balancer. Ask yourself:
- Is it Global or Regional? (HTTP(S) is global; Network is regional).
- Is it Layer 7 or Layer 4? (HTTP(S) is Layer 7; Proxy/Network are Layer 4).
- Is it Internal or External? (Public-facing or VPC-only?).
Frequently Asked Questions (FAQ)
What is Shared VPC?
Shared VPC allows an organization to connect resources from multiple projects to a common Virtual Private Cloud (VPC) network, allowing for centralized network management while maintaining project-level autonomy.
How do I secure my VPC?
By using Firewall Rules (or Network Firewall Policies), Cloud IAP for administrative access, and VPC Service Controls to prevent data exfiltration.
What is Cloud Armor?
Cloud Armor is GCP's distributed denial-of-service (DDoS) defense and web application firewall (WAF) service that works with the External HTTP(S) Load Balancer to protect your apps.
How to secure hybrid connectivity?
Use Cloud VPN with IPsec for encryption or Cloud Interconnect for reliability. For administrative access, always favor Identity-Aware Proxy.
What load balancer for EHR Healthcare?
Since EHR needs a global presence, use the Global External HTTP(S) Load Balancer with Cloud Armor and IAP — check our EHR guide.
Exam Gold: If the question mentions **IPv6, SSL Offloading, or Global Scale**, the answer is almost always the **Global External HTTP(S) Load Balancer**.
Hybrid Connectivity: VPN vs. Interconnect
Connecting your on-prem data center to GCP? Use this logic:
- Cloud VPN: Low cost, quick setup, encrypted over public internet. Great for < 1-2 Gbps.
- Dedicated Interconnect: Highest performance (10/100 Gbps), physically connected cabling. Best for critical enterprise data.
- Partner Interconnect: Connect via a provider (like Equinix). Good middle ground.
Summary for Exam Day
Master these three things and you'll crush the networking section:
- Understand **Firewall Rules** (they are stateful and implied deny all).
- Know the difference between **Alias IP** (GKE pods) and secondary ranges.
- Memorize the **Cloud Load Balancing flow-chart**.
Struggling with VPC design?
Practice with our GKE and Networking specific mock tests to master these concepts.
Practice Networking Questions