Why it matters
Global VPCs simplify multi-region architectures. Where AWS needs careful VPC peering setup for cross-region traffic, GCP has one VPC that spans regions. This is a genuine engineering advantage.
The architecture
A VPC is a global network. Subnets are regional; each subnet is one CIDR block in one region. Instances in subnets can talk to instances in any other subnet in the VPC over the private backbone.
Firewall rules are global too. A rule applies to all matching instances across the entire VPC.
How it works end to end
Shared VPC lets multiple projects share a central network. Great for enterprise: one team owns network, others own workloads.
Private Google Access lets private-IP-only VMs reach Google APIs (Cloud Storage, BigQuery) without public internet.
Cloud Interconnect provides dedicated private connectivity to on-prem. Partner Interconnect and Dedicated Interconnect offer different capacity tiers.