To generate an alert while throughput exceeds your described values, create a CloudWatch alarm with an Amazon Simple Notification Service (Amazon SNS) notification.

To intend throughput for a Transit Gateway and set up a CloudWatch alarm, you can follow these steps:

1. Log in to the AWS Management Console.

2. Open the Amazon CloudWatch console at

3. In the navigation pane, click on "Alarms" and then click on the "Create alarm" button.

4.  Select the "Transit Gateway" namespace.

5. In the "Create Alarm" wizard, specify the conditions for your alarm:

      a. Under "Conditions", select the appropriate metric for throughput. For example, you can choose the "BytesIn" or "BytesOut" metric depending on the direction you want to monitor.

       b. Choose the appropriate statistic (e.g., Average, Maximum, etc.) for the metric.

       c. Specify the threshold values for triggering the alarm. This can be an absolute value or a dynamic threshold based on the baseline or anomaly detection.

        d. Set the evaluation period. This is the time period over which CloudWatch evaluates the metric against the threshold.

        e. Configure the actions to be taken when the alarm state is triggered, such as sending a notification or performing an automated action.

6. Provide a name and description for your alarm.

7. Choose the appropriate options for the alarm, such as the period, data retention, and actions.

8. Review the alarm configuration and click on the "Create alarm" button to create the CloudWatch alarm.

Once the alarm is created, CloudWatch will monitor the specified metric for the Transit Gateway and trigger the alarm based on the defined conditions. You can view the status of the alarm in the CloudWatch console and configure additional notifications or actions as needed.