A company operates public applications in the US and Europe using three transit gateways in us-west-2, us-east-1, and eu-central-1 that are fully meshed. The company accidentally removed the route to the eu-central-1 VPCs from the us-west-2 transit gateway route table and also removed the route to the us-west-2 VPCs from the eu-central-1 transit gateway route table. How can a network engineer detect this misconfiguration with the least operational overhead?

The Route Analyzer feature within AWS Transit Gateway Network Manager is designed precisely for scenarios like this. It allows you to specify a source and destination, and it will analyze the routing paths across your Transit Gateway network, identifying any missing or incorrect routes. This provides a direct and efficient way to pinpoint routing misconfigurations with minimal effort. Other options are less efficient: AWSSupport-SetupIPMonitoringFromVPC is for general IP monitoring and doesn't specifically analyze Transit Gateway routes. VPC Flow Logs show traffic that did flow, not what should flow, making it difficult to detect missing routes without extensive analysis. VPC Traffic Mirroring captures packet data, which is useful for deep-dive troubleshooting of existing traffic but not for proactively identifying missing routes in the routing tables themselves.