Two companies are merging and each has a substantial AWS footprint with multiple VPCs. Both use Direct Connect with a Direct Connect gateway, and each has a Transit Gateway plus multiple Site-to-Site VPNs from its Transit Gateway to on-premises. The new design must maximize network visibility, throughput, logging, and monitoring. Which architecture meets these goals?

The correct option leverages Transit Gateway peering, which is the most scalable and performant method for connecting two Transit Gateways, offering higher throughput than Site-to-Site VPNs between them. VPC Flow Logs to CloudWatch provide comprehensive network visibility and logging for all VPC traffic. AWS Transit Gateway Network Manager is the ideal tool for centralized monitoring of Transit Gateways, their attachments (including Direct Connect, VPNs, and VPCs), and crucially, Transit Gateway peering connections, fulfilling the requirement for maximum visibility and monitoring. The incorrect options propose Site-to-Site VPNs between Transit Gateways, which is less efficient and performant than peering. While VPC Reachability Analyzer is useful for troubleshooting specific reachability issues, AWS Transit Gateway Network Manager offers a broader, centralized monitoring solution for the entire Transit Gateway network, including peering links.