# Create a transit virtual interface to the Amazon Direct Connect gateway To connect your Amazon Direct Connect connection to the transit gateway, you must create a transit interface for your connection. Specify the Direct Connect gateway to which to connect. You can use either the Amazon Direct Connect console or use the command line or API. **Important** If you associate your transit gateway with one or more Direct Connect gateways, the Autonomous System Number (ASN) used by the transit gateway and the Direct Connect gateway must be different. For example, if you use the default ASN 64512 for both the transit gateway and the Direct Connect gateway, the association request fails. **To provision a transit virtual interface to a Direct Connect gateway** 1. Open the **Amazon Direct Connect** console at [https://console.amazonaws.cn/directconnect/v2/home](https://console.amazonaws.cn/directconnect/v2/home). 1. In the navigation pane, choose **Virtual Interfaces**. 1. Choose **Create virtual interface**. 1. Under **Virtual interface type**, for **Type**, choose **Transit**. 1. Under **Transit virtual interface settings**, do the following: 1. For **Virtual interface name**, enter a name for the virtual interface. 1. For **Connection**, choose the Direct Connect connection that you want to use for this interface. 1. For **Virtual interface owner**, choose **My Amazon account** if the virtual interface is for your Amazon account. 1. For **Direct Connect gateway**, select the Direct Connect gateway. 1. For **VLAN**, enter the ID number for your virtual local area network (VLAN). 1. For **BGP ASN**, enter the Border Gateway Protocol Autonomous System Number of your on-premises peer router for the new virtual interface. The valid values are 1 to 4294967294. This includes support for both ASNs (1-2147483647) and long ASNs (1-4294967294). For more information about ASNs and long ASNs see [Long ASN support in Amazon Direct Connect](long-asn-support.md). 1. Under **Additional Settings**, do the following: 1. To configure an IPv4 BGP or an IPv6 peer, do the following: [IPv4] To configure an IPv4 BGP peer, choose **IPv4** and do one of the following: + To specify these IP addresses yourself, for **Your router peer ip**, enter the destination IPv4 CIDR address to which Amazon should send traffic. + For **Amazon router peer ip**, enter the IPv4 CIDR address to use to send traffic to Amazon. **Important** When configuring Amazon Direct Connect virtual interfaces, you can specify your own IP addresses using RFC 1918, use other addressing schemes, or opt for Amazon assigned IPv4 /29 CIDR addresses allocated from the RFC 3927 169.254.0.0/16 IPv4 Link-Local range for point-to-point connectivity. These point-to-point connections should be used exclusively for eBGP peering between your customer gateway router and the Direct Connect endpoint. For VPC traffic or tunnelling purposes, such as Amazon Site-to-Site Private IP VPN, or Transit Gateway Connect, Amazon recommends using a loopback or LAN interface on your customer gateway router as the source or destination address instead of the point-to-point connections. For more information about RFC 1918, see [Address Allocation for Private Internets](https://datatracker.ietf.org/doc/html/rfc1918). For more information about RFC 3927, see [Dynamic Configuration of IPv4 Link-Local Addresses](https://datatracker.ietf.org/doc/html/rfc3927). [IPv6] To configure an IPv6 BGP peer, choose **IPv6**. The peer IPv6 addresses are automatically assigned from Amazon's pool of IPv6 addresses. You cannot specify custom IPv6 addresses. 1. To change the maximum transmission unit (MTU) from 1500 (default) to 8500 (jumbo frames), select **Jumbo MTU (MTU size 8500)**. 1. (Optional) Under **Enable SiteLink**, choose **Enabled** to enable direct connectivity between Direct Connect points of presence. 1. (Optional) For **Bandwidth**, select a bandwidth value to apply a Rate Limiter to this virtual interface. The Rate Limiter sets a maximum bandwidth that the VIF can use, helping prevent this VIF from congesting other VIFs on the same connection. This option is only available on Dedicated connections. For more information, see [Virtual interface Rate Limiters](vif-rate-limiters.md). 1. (Optional) Add or remove a tag. [Add a tag] Choose **Add tag** and do the following: + For **Key**, enter the key name. + For **Value**, enter the key value. [Remove a tag] Next to the tag, choose **Remove tag**. 1. Choose **Create virtual interface**. After you've created the virtual interface, you can download the router configuration for your device. For more information, see [Download the router configuration file](vif-router-config.md). **To create a transit virtual interface using the command line or API** + [create-transit-virtual-interface](https://docs.amazonaws.cn/cli/latest/reference/directconnect/create-transit-virtual-interface.html) (Amazon CLI) + [CreateTransitVirtualInterface](https://docs.amazonaws.cn/directconnect/latest/APIReference/API_CreateTransitVirtualInterface.html) (Amazon Direct Connect API) **To view the virtual interfaces that are attached to a Direct Connect gateway using the command line or API** + [describe-direct-connect-gateway-attachments](https://docs.amazonaws.cn/cli/latest/reference/directconnect/describe-direct-connect-gateway-attachments.html) (Amazon CLI) + [DescribeDirectConnectGatewayAttachments](https://docs.amazonaws.cn/directconnect/latest/APIReference/API_DescribeDirectConnectGatewayAttachments.html) (Amazon Direct Connect API)