AWS Transit Gateway

Introduction

Consider the following scenario: we need to connect several VPCs so that the resources within them can communicate. So far, we’ve learned that VPC peering can connect two VPCs at a time, which means that several VPCs will necessitate a large number of peering connections.

The number of connections will further increase if we also need to connect the VPCs to an on-prem network using either Site-to-Site VPN or Direct Connect, leading to a complex network architecture.

For example, if we want to interconnect four VPCs, VPC A, VPC B, VPC C, and VPC D, we would require a total of six peering connections, as shown in the diagram below.