Transit gateway route tables in Amazon VPC Transit Gateways

Use transit gateway route tables to configure routing for your transit gateway attachments. A route table is a table that contains rules that direct how your network traffic is routed between your VPCs and VPNs. Each route in the table contains the range of IP addresses for the destinations that you want to send traffic to.

Transit gateway route tables allows you to associate a table with a transit gateway attachment. VPC, VPN, Direct Connect gateway, Peering, and Connect attachments are all supported. When associated, routes for these attachments are propagated from the attachment to the target transit gateway route table. An attachment can be propagated to multiple route tables.

Additionally you can create and manage static routes with a route table. For example, you might have a static route that's used as a backup route in the event of a network disruption that affects any dynamic routes.

Prefix list references

You can reference a prefix list in your transit gateway route table. A prefix list is a set of one or more CIDR block entries that you define and manage. You can use a prefix list to simplify the management of the IP addresses that you reference in your resources to route network traffic. For example, if you frequently specify the same destination CIDRs across multiple transit gateway route tables, you can manage those CIDRs in a single prefix list, instead of repeatedly referencing the same CIDRs in each route table. If you need to remove a destination CIDR block, you can remove its entry from the prefix list instead of removing the route from every affected route table.

When you create a prefix list reference in your transit gateway route table, each entry in the prefix list is represented as a route in your transit gateway route table.

For more information about prefix lists, see Prefix lists in the Amazon VPC User Guide.