What is a Transit Gateway?

A Transit Gateway is a network transit hub that enables you to connect multiple VPCs, VPNs, and on-premises networks to streamline network connectivity and management within your AWS infrastructure.

How does a Transit Gateway Work?

Transit Gateways act as a central hub for routing traffic between connected networks. They simplify network architecture by providing a single point of entry and exit for traffic, reducing the need for complex VPC peering configurations.

Setting Up a Transit Gateway

To set up a Transit Gateway:

  1. Navigate to the Transit Gateway Console: Access the AWS Management Console and navigate to the Transit Gateway service.

  2. Create a Transit Gateway: Click on "Create Transit Gateway" and provide details such as name, description, and Amazon side ASN (Autonomous System Number).

  3. Add Attachments: Attach VPCs, VPN connections, and Direct Connect gateways to the Transit Gateway to establish connectivity.

  4. Configure Route Tables: Define route tables to specify how traffic should be routed between attached networks.

  5. Propagation of Routes: Propagate routes from attached VPCs or VPN connections to ensure proper routing of traffic.

  6. Associate Subnets: Associate subnets from attached VPCs with the Transit Gateway to enable communication between resources.

  7. Testing and Validation: Test connectivity between resources in different networks to ensure proper routing through the Transit Gateway.

Benefits of Using a Transit Gateway

  1. Simplified Network Architecture: Transit Gateways simplify network connectivity by providing a centralized hub for routing traffic.

  2. Scalability: They support the connection of thousands of VPCs and on-premises networks, allowing for scalable network expansion.

  3. Cost-Effective: Transit Gateways eliminate the need for multiple VPN connections and complex VPC peering arrangements, reducing operational costs.

Considerations

  1. Data Transfer Costs: Data transfer costs may apply for traffic traversing the Transit Gateway between regions or across AWS services.

  2. High Availability: Deploy Transit Gateways across multiple Availability Zones for high availability and fault tolerance.

  3. By leveraging Transit Gateways, you can establish a scalable and efficient network architecture in AWS, facilitating seamless communication between VPCs, VPNs, and on-premises networks.

Happy networking with Transit Gateways!