*** This version of Confluence is for testing only and contains a copy of content from June 29th 2026. No changes will be preserved. ***
...
The AWS Transit Gateways used in the v2 architecture require different routing rules than the Virtual Private Gateways (VGW) used in the v1 architecture. Each VPC Route Table that references a Virtual Private Gateway will be duplicated and, in the new Route Table, rules referencing a VGW will be replaced with rules referencing a TGW Attachment. The new Route Tables will not include "blackhole" routes (i.e. routes to resources, like old peering connections, that no longer exist) from the original Route Tables.
These new Route Tables will be created prior to the migration, but will not actually be utilized until the migration is executed. When migration is executed, subnets associated with the v1 Route Tables will be re-associated to the corresponding v2 Route Tables. Similarly, if the "main" Route Table for the VPC references a VGW, the corresponding v2 Route Table will be set as the "main" Route Table for the VPC.
...