You are planning a large application deployment in Google Cloud that includes on-premises connectivity. The application requires direct connectivity between workloads in all regions and on- premises…

Using multiple VPC networks with a transit network via VPC Network Peering addresses inter-VPC connectivity but does not solve the fundamental issue of exhausted RFC 1918 ranges on-premises or provide unique non-overlapping IP spaces if new VPCs also use RFC 1918 ranges that clash.

Using overlapping RFC 1918 ranges with multiple isolated VPC networks explicitly violates the requirement for 'direct connectivity between workloads... without address translation' because overlapping IP spaces would necessitate network address translation (NAT) or other complex routing solutions.

Using overlapping RFC 1918 ranges with multiple isolated VPC networks and Cloud NAT introduces address translation, which directly contradicts the requirement for connectivity 'without address translation'.

If all RFC 1918 address ranges are in use on-premises and the requirement is for direct connectivity without address translation, Google Cloud allows the use of non-RFC 1918 (publicly routable) IP address ranges for VPC networks. Implementing these non-RFC 1918 ranges within a single global VPC ensures unique, non-overlapping private IP spaces for Google Cloud resources and enables direct communication with on-premises locations and across all regions without needing NAT.