Your company has 10 separate Virtual Private Cloud (VPC) networks, with one VPC per project in a single region in Google Cloud. Your security team requires each VPC network to have private…

Configuring multiple interfaces and specific Partner Interconnects for each VPC implies individual connections, which would not optimize cost or operations for sharing connectivity across 10 VPCs and doesn't inherently centralize inspection.

Configuring multiple interfaces, with each connected to a separate VPC, would still mean managing appliance deployments across multiple VPCs or complex routing if not within a shared transit model, which contradicts optimizing cost, operations, and centralizing inspection.

Consolidating all existing projects' subnetworks into a single VPC would simplify the network but could create an overly complex and large single point of failure, potentially conflicting with project separation needs, and does not explicitly detail how third-party appliances would inspect traffic between different projects or on-premises.

To inspect all traffic (inter-VPC, on-premises, and internet) using the same third-party appliances, a hub-and-spoke or transit VPC architecture is implied where all relevant traffic is routed through a central VPC. In this central VPC, the third-party appliances would be configured with multiple interfaces to handle ingress and egress traffic from the Partner Interconnect, peered VPCs, and the internet, ensuring centralized inspection and optimized cost by sharing a single set of appliances.