2.2. Inter-VPC Connectivity

As AWS environments grow, organizations often deploy workloads into multiple VPCs for isolation, security, or organizational reasons. Efficient and secure communication between these VPCs becomes critical. This section explores the primary AWS services for connecting VPCs, from simple peering to the scalable Transit Gateway, enabling complex enterprise network architectures.

Scenario: You need to connect several VPCs to enable communication between applications running in different environments or across different business units, all within AWS.

💡 First Principle: Scalable and secure inter-VPC connectivity enables modular network designs, facilitates shared services, and controls traffic flow between isolated environments without routing over the public internet. This allows for complex enterprise architectures.

This section explores the two primary AWS services for connecting VPCs: VPC Peering and AWS Transit Gateway (TGW).

⚠️ Common Pitfall: Choosing VPC Peering for a large number of VPCs. This creates a complex and unmanageable "peering mesh" that is difficult to troubleshoot and scale.

Key Trade-Offs:

• Simplicity (Peering) vs. Scalability (Transit Gateway): VPC Peering is simple for connecting two or three VPCs. Transit Gateway has a slightly higher initial setup cost and complexity but is vastly more scalable and manageable for enterprise-wide networking.

Reflection Question: How do scalable and secure inter-VPC connectivity options (e.g., VPC Peering, Transit Gateway) fundamentally enable modular network designs and controlled traffic flow between isolated environments within AWS?