# Register sources with a multicast group in AWS Transit Gateway
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**Note**  
This procedure is only required when you have set the **Static sources support** attribute to **enable**.

Use the following procedure to register sources with a multicast group. The source is the network interface that sends multicast traffic.

You need the following information before you add a source:
+ The ID of the multicast domain
+ The IDs of the sources' network interfaces
+ The multicast group IP address

**To register sources using the console**

1. Open the Amazon VPC console at [https://console.aws.amazon.com/vpc/](https://console.aws.amazon.com/vpc/).

1. On the navigation pane, choose **Transit Gateway Multicast**.

1. Select the multicast domain, and then choose **Actions**, **Add group sources**.

1. For **Group IP address**, enter either the IPv4 CIDR block or IPv6 CIDR block to assign to the multicast domain.

1. Under **Choose network interfaces**, select the multicast senders' network interfaces.

1. Choose **Add sources**.

**To register sources using the AWS CLI**  
Use the [register-transit-gateway-multicast-group-sources](https://docs.aws.amazon.com/cli/latest/reference/ec2/register-transit-gateway-multicast-group-sources.html) command.