Transit Gateway
Transit Gateway is a fully managed service by AWS that provides a hub and spoke model for connecting multiple VPCs and VPN connections. It simplifies the network architecture by allowing inter-VPC communication and VPN connectivity through a central hub.
Key Benefits of Transit Gateway:
Simplified routing: Transit Gateway allows you to create a single point of entry and exit for traffic between VPCs and VPN connections. This simplifies the routing configuration as you only need to create and configure routes in the Transit Gateway.
Scalability: Transit Gateway supports up to 5,000 VPC attachments, providing the ability to connect a large number of VPCs and VPN connections within your AWS infrastructure.
Cost-effective: By using Transit Gateway, you can reduce the number of VPN connections required and streamline the traffic flow between VPCs. This helps in reducing network traffic costs and simplifying network management.
Example Usage
Here's an example of how Transit Gateway can be used to connect multiple VPCs:
1 class Main {
2 public static void main(String[] args) {
3 // Create a Transit Gateway
4 TransitGateway transitGateway = new TransitGateway("tgw-12345678");
5
6 // Creating VPC attachments
7 VpcAttachment attachment1 = transitGateway.createVpcAttachment("vpc-12345678", "tgw-12345678", "subnet-12345678");
8 VpcAttachment attachment2 = transitGateway.createVpcAttachment("vpc-87654321", "tgw-12345678", "subnet-87654321");
9
10 // Create route tables for each VPC
11 RouteTable routeTable1 = transitGateway.createRouteTable("rtb-12345678", "vpc-12345678");
12 RouteTable routeTable2 = transitGateway.createRouteTable("rtb-87654321", "vpc-87654321");
13
14 // Add routes to the route tables
15 routeTable1.addRoute("10.0.0.0/16", attachment1);
16 routeTable2.addRoute("10.0.0.0/16", attachment2);
17
18 // Enable DNS resolution
19 transitGateway.enableDnsResolution();
20
21 // Enable DNS hostnames
22 transitGateway.enableDnsHostnames();
23 }
24 }xxxxxxxxxxclass Main { public static void main(String[] args) { // Create a Transit Gateway TransitGateway transitGateway = new TransitGateway("tgw-12345678"); // Creating VPC attachments VpcAttachment attachment1 = transitGateway.createVpcAttachment("vpc-12345678", "tgw-12345678", "subnet-12345678"); VpcAttachment attachment2 = transitGateway.createVpcAttachment("vpc-87654321", "tgw-12345678", "subnet-87654321"); // Create route tables for each VPC RouteTable routeTable1 = transitGateway.createRouteTable("rtb-12345678", "vpc-12345678"); RouteTable routeTable2 = transitGateway.createRouteTable("rtb-87654321", "vpc-87654321"); // Add routes to the route tables routeTable1.addRoute("10.0.0.0/16", attachment1); routeTable2.addRoute("10.0.0.0/16", attachment2); // Enable DNS resolution transitGateway.enableDnsResolution(); // Enable DNS hostnames transitGateway.enableDnsHostnames(); }}