When an application spans multiple regions, the Cloud VPN topology has to span them too. A single VPN gateway in one region forces all traffic from the other region to take a longer hop, which adds latency and burns egress dollars. The Professional Cloud Architect exam expects you to recognize this pattern and pick the right gateway layout for a given footprint.
Picture an application running on VMs in us-west1 and us-east4, all sitting inside the same VPC. The application needs a secure connection back to an on-premises office network, or to a network in another cloud. With a single Cloud VPN gateway in us-west1, every packet from the us-east4 instances has to cross the VPC backbone to us-west1 before it can leave through the tunnel. That is wasted distance for traffic that ultimately needs to reach a peer outside Google Cloud.
The right answer is to deploy a Cloud VPN gateway in every region where the application runs. The gateway in us-west1 handles the tunnel for workloads in that region, and the gateway in us-east4 handles its own region. The on-premises network terminates both tunnels on its side, so each region has a direct path out of Google Cloud.
Two things fall out of that layout. Latency drops because traffic exits at the closest gateway instead of hairpinning across the continent. Egress costs drop for the same reason: traffic stays local to the region until it leaves through the tunnel, so you avoid inter-region charges on the VPC side.
Once you have two gateways, you also have two independent failure domains. If the tunnel from us-west1 goes down, or if the entire region has a problem, the us-east4 gateway is still up and can carry traffic to the on-premises network. You did not deploy the second gateway for redundancy, but you get redundancy anyway because the topology demands it.
That is the kind of detail the Professional Cloud Architect exam likes to test. A scenario describes a multi-region application that needs to talk to a corporate network, and the answer choices include single-gateway and multi-gateway options. The correct choice is almost always the one that puts a gateway in each application region, because it solves both the performance problem and the availability problem in one move.
If an application is multi-regional and needs Cloud VPN connectivity, deploy a Cloud VPN gateway in each region. That keeps traffic local, controls egress costs, and gives you regional failure isolation without any additional configuration. A single-gateway design is the wrong answer once the workload itself is spread across regions.
My Professional Cloud Architect course covers multi-region Cloud VPN configuration alongside the rest of the networking material.
