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

Common properties for creating a Transit Gateway resource.

Extends: TransitGatewayProps
Used as props by: TransitGateway

- Stability: [Experimental](/cdk/api/stability.html)
- Source: [`lib/transit-gateway.ts`](https://github.com/aws/aws-cdk/blob/v2.275.0-alpha.0/packages/@aws-cdk/aws-ec2-alpha/lib/transit-gateway.ts#L75)

## Example

```ts
const transitGateway = new TransitGateway(this, 'MyTransitGateway', {
  defaultRouteTableAssociation: false,
  defaultRouteTablePropagation: false,
});
```

## Properties

- `amazonSideAsn`: number — A private Autonomous System Number (ASN) for the Amazon side of a BGP session.

  **Default:** undefined, 64512 is assigned by CloudFormation.

  The range is 64512 to 65534 for 16-bit ASNs.

- `autoAcceptSharedAttachments`: boolean — Enable or disable automatic acceptance of cross-account attachment requests.

  **Default:** disable (false)

- `defaultRouteTableAssociation`: boolean — Enable or disable automatic association with the default association route table.

  **Default:** enable (true)

- `defaultRouteTablePropagation`: boolean — Enable or disable automatic propagation of routes to the default propagation route table.

  **Default:** enable (true)

- `description`: string — The description of the transit gateway.

  **Default:** no description

- `dnsSupport`: boolean — Enable or disable DNS support.

  **Default:** enable (true)

  If dnsSupport is enabled on a VPC Attachment, this also needs to be enabled for the feature to work.
  Otherwise the resources will still deploy but the feature will not work.

- `securityGroupReferencingSupport`: boolean — Enable or disable security group referencing support.

  **Default:** disable (false)

  If securityGroupReferencingSupport is enabled on a VPC Attachment, this also needs to be enabled for the feature to work.
  Otherwise the resources will still deploy but the feature will not work.

- `transitGatewayCidrBlocks`: string[] = none — The transit gateway CIDR blocks.

- `transitGatewayName`: string — Physical name of this Transit Gateway.

  **Default:** Assigned by CloudFormation.