Psc Internal Load Balancer N Tier Encapsulation

What the Recommended Architecture Is

This architecture combines Private Service Connect (PSC), Internal Application Load Balancers (Envoy-based L7 ILBs) with dedicated proxy-only subnets, and Private Google Access to enforce zero-trust boundary segmentation and complete data encapsulation for multi-tier applications.

How It Meets the Requirements

• Microservice encapsulation without peering: Private Service Connect creates unidirectional, service-oriented endpoints in the consumer VPC mapped to service attachments in the producer VPC. It completely eliminates the need for bidirectional VPC Network Peering, preventing lateral transit paths, IP CIDR conflicts, and peering quota limits.
• Private Google API reachability: Enabling Private Google Access on the backend subnets allows VM instances assigned solely RFC 1918 internal IP addresses to route securely to Google APIs (such as Cloud Storage and BigQuery) across Google's internal software-defined network (SDN) backplane without traversing the public internet.
• Internal Layer 7 traffic routing: Deploying an Internal Application Load Balancer provides regional Layer 7 load balancing, SSL/TLS termination, and path-based routing. The load balancer allocates Envoy proxies within a dedicated proxy-only subnet (purpose=REGIONAL_MANAGED_PROXY) to handle proxying and header inspection without exposing workload IP addresses.

Key Advantages and Capabilities

• Decoupled address spaces: PSC allows producer and consumer VPCs to have overlapping IP address ranges since communication is encapsulated via endpoint forwarding rules.
• Explicit authorization: Service attachments enable granular consumer accept/reject lists with project-level access controls.
• No transitive exposure: Protects internal tiers from lateral movement by strictly isolating L4/L7 access to declared service endpoints.
• Zero internet exposure: Backend data tiers operate without external public IP addresses or NAT gateway egress requirements for Google API consumption.

Why This Is Optimal

This architecture strictly isolates each tier's fault domain and network perimeter while providing line-rate performance and comprehensive Layer 7 traffic management.