Create a transit gateway using Amazon VPC Transit Gateways - Amazon VPC

Create a transit gateway using Amazon VPC Transit Gateways

When you create a transit gateway, we create a default transit gateway route table and use it as the default association route table and the default propagation route table. If you choose not to create the default transit gateway route table, you can create one later on. For more information about routes and route tables, see Routing.

To create a transit gateway using the console

  1. Open the Amazon VPC console at https://console.aws.amazon.com/vpc/.

  2. On the navigation pane, choose Transit Gateways.

  3. Choose Create transit gateway.

  4. For Name tag, optionally enter a name for the transit gateway. A name tag can make it easier to identify a specific gateway from the list of gateways. When you add a Name tag, a tag is created with a key of Name and with a value equal to the value you enter.

  5. For Description, optionally enter a description for the transit gateway.

  6. For Amazon side Autonomous System Number (ASN), either leave the default value to use the default ASN or enter the private ASN for your transit gateway. This should be the ASN for the AWS side of a Border Gateway Protocol (BGP) session.

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

    The range is 4200000000 to 4294967294 for 32-bit ASNs.

    If you have a multi-Region deployment, we recommend that you use a unique ASN for each of your transit gateways.

  7. For DNS support, select this option if you need the VPC to resolve public IPv4 DNS host names to private IPv4 addresses when queried from instances in another VPC attached to the transit gateway.

  8. For Security Group Referencing support, enable this feature to reference a security group across VPCs attached to a transit gateway. For more information about security group referencing see Security group referencing.

  9. For VPN ECMP support, select this option if you need Equal Cost Multipath (ECMP) routing support between VPN tunnels. If connections advertise the same CIDRs, the traffic is distributed equally between them.

    When you select this option, the advertised BGP ASN, then the BGP attributes such as the AS-path, must be the same.

    Note

    To use ECMP, you must create a VPN connection that uses dynamic routing. VPN connections that use static routing do not support ECMP.

  10. For Default route table association, select this option to automatically associate transit gateway attachments with the default route table for the transit gateway.

  11. For Default route table propagation, select this option to automatically propagate transit gateway attachments to the default route table for the transit gateway.

  12. (Optional) To use the transit gateway as a router for multicast traffic, select Multicast support.

  13. (Optional) In the Configure-cross-account sharing options section, choose whether to Auto accept shared attachments. If enabled, attachments are automatically accepted. Otherwise, you must accept or reject attachment requests.

    For Auto accept shared attachments, select this option to automatically accept cross-account attachments.

  14. (Optional) For Transit gateway CIDR blocks, specify one or more IPv4 or IPv6 CIDR blocks for your transit gateway.

    You can specify a size /24 CIDR block or larger (for example, /23 or /22) for IPv4, or a size /64 CIDR block or larger (for example, /63 or /62) for IPv6. You can associate any public or private IP address range, except for addresses in the 169.254.0.0/16 range, and ranges that overlap with the addresses for your VPC attachments and on-premises networks.

    Note

    Transit gateway CIDR blocks are used if you are configuring Connect (GRE) attachments or PrivateIP VPNs. Transit Gateway assigns IPs for the Tunnel endpoints (GRE/PrivateIP VPN) from this range.

  15. Choose Create transit gateway.

To create a transit gateway using the AWS CLI

Use the create-transit-gateway command.