> **Experimental**
>
> `@aws-cdk/aws-ec2-alpha` is an [**experimental**](/stability) (alpha) package: its API may change in any release, without a major version bump.
# ITransitGateway

Represents a Transit Gateway.

Extends: ITransitGateway
Extends: IResource, IRouteTarget
Implemented by: TransitGateway

- Stability: [Experimental](/cdk/api/stability.html)
- Source: [`lib/transit-gateway.ts`](https://github.com/aws/aws-cdk/blob/v2.274.0-alpha.0/packages/@aws-cdk/aws-ec2-alpha/lib/transit-gateway.ts#L18)

## Properties

- `defaultRouteTable`: [ITransitGatewayRouteTable](/cdk/api/v2/docs/@aws-cdk_aws-ec2-alpha.ITransitGatewayRouteTable.html) (required) — The default route table associated with the Transit Gateway.

  This route table is created by the CDK and is used to manage the routes
  for attachments that do not have an explicitly defined route table association.

- `defaultRouteTableAssociation`: boolean (required) — Indicates whether new attachments are automatically associated with the default route table.

  If set to `true`, any VPC or VPN attachment will be automatically associated with
  the default route table unless otherwise specified.

- `defaultRouteTablePropagation`: boolean (required) — Indicates whether route propagation to the default route table is enabled.

  When set to `true`, routes from attachments will be automatically propagated
  to the default route table unless propagation is explicitly disabled.

- `dnsSupport`: boolean (required) — Whether or not DNS support is enabled on the Transit Gateway.

- `env`: [ResourceEnvironment](/cdk/api/v2/docs/aws-cdk-lib.interfaces.ResourceEnvironment.html) (required) — The environment this resource belongs to.

  For resources that are created and managed in a Stack (those created by
  creating new class instances like `new Role()`, `new Bucket()`, etc.), this
  is always the same as the environment of the stack they belong to.

  For referenced resources (those obtained from referencing methods like
  `Role.fromRoleArn()`, `Bucket.fromBucketName()`, etc.), they might be
  different than the stack they were imported into.

- `node`: [Node](/cdk/api/v2/docs/constructs.Node.html) (required) — The tree node.

- `routerTargetId`: string (required) — The ID of the route target.

- `routerType`: [RouterType](/cdk/api/v2/docs/aws-cdk-lib.aws_ec2.RouterType.html) (required) — The type of router used in the route.

- `securityGroupReferencingSupport`: boolean (required) — Whether or not security group referencing support is enabled on the Transit Gateway.

- `stack`: [Stack](/cdk/api/v2/docs/aws-cdk-lib.Stack.html) (required) — The stack in which this resource is defined.

- `transitGatewayArn`: string (required) — The Amazon Resource Name (ARN) of the Transit Gateway.

  The ARN uniquely identifies the Transit Gateway across AWS and is commonly
  used for permissions and resource tracking.

- `transitGatewayId`: string (required) — The unique identifier of the Transit Gateway.

  This ID is automatically assigned by AWS upon creation of the Transit Gateway
  and is used to reference it in various configurations and operations.

## Methods

- `applyRemovalPolicy(policy: RemovalPolicy): void` — Apply the given removal policy to this resource.

  The Removal Policy controls what happens to this resource when it stops
  being managed by CloudFormation, either because you've removed it from the
  CDK application or because you've made a change that requires the resource
  to be replaced.

  The resource can be deleted (`RemovalPolicy.DESTROY`), or left in your AWS
  account for data recovery and cleanup later (`RemovalPolicy.RETAIN`).

- `with(...mixins: IMixin[]): IConstruct` — Applies one or more mixins to this construct.

  Mixins are applied in order. The list of constructs is captured at the
  start of the call, so constructs added by a mixin will not be visited.

  **Parameters**

  - `mixins` — The mixins to apply.

  **Returns:** This construct for chaining