Example: Allowed to prefixes in a transit gateway configuration
Consider the configuration where you have instances in two different AWS Regions which need to access the corporate data center. You can use the following resources for this configuration:
-
A transit gateway in each Region.
-
A transit gateway peering connection.
-
A Direct connect gateway.
-
A transit gateway association between one of the transit gateways (the one in us-east-1) to the Direct Connect gateway.
-
A transit virtual interface from the on-premises location and the AWS Direct Connect location.
Configure the following options for the resources.
-
Direct Connect gateway: Set the ASN for to 65030. For more information, see Creating a Direct Connect gateway.
-
Transit virtual interface: Set the VLAN to 899, and the ASN to 65020. For more information, see Create a transit virtual interface to the Direct Connect gateway.
-
Direct Connect gateway association with the transit gateway: Set the allowed to prefixes to 10.0.0.0/8.
This CIDR block covers both VPC CIDR blocks. For more information, see Associating and disassociating transit gateways.
-
VPC route: To route traffic from the 10.2.0.0 VPC, create a route in the VPC route table which has a Destination of 0.0.0.0/0 and the transit gateway ID as the Target. For more information about routing to a transit gateway, see Routing for a transit gateway in the Amazon VPC User Guide.
