# Monitor your global network with Amazon CloudWatch metrics
Monitor with CloudWatch metrics

You can monitor AWS Global Networks for Transit Gateways using Amazon CloudWatch, which collects raw data and processes it into readable, near-real-time metrics. These statistics are kept for 15 months, so that you can access historical information and gain a better perspective on how your web application or service is performing. You can also set alarms that watch for certain thresholds, and send notifications or take actions when those thresholds are met. For more information, see the [Amazon CloudWatch User Guide](https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/).

You can view CloudWatch metrics in your global network for your registered transited gateways, your associated Site-to-Site VPN connections, and your on-premises resources. You can view metrics per transit gateway and per transit gateway attachment, per global network.

For more information about the supported metrics, see the following topics:
+ [CloudWatch metrics for your transit gateways](https://docs.aws.amazon.com/vpc/latest/tgw/transit-gateway-cloudwatch-metrics.html)
+ [Monitor VPN tunnels using Amazon CloudWatch](https://docs.aws.amazon.com/vpn/latest/s2svpn/monitoring-cloudwatch-vpn.html)
+ [View CloudWatch metrics for on-premises resources](cw-metrics-on-premises.md)

For examples of creating alarms, see [Creating Amazon CloudWatch Alarms](https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/AlarmThatSendsEmail.html) in the *Amazon CloudWatch User Guide*.

# View CloudWatch metrics for on-premises resources


AWS Global Networks for Transit Gateways publishes data points to Amazon CloudWatch for your on-premises resources, including devices and links. CloudWatch enables you to retrieve statistics about those data points as an ordered set of time series data, known as metrics. Each data point has an associated timestamp and an optional unit of measurement. 

You can use metrics to verify that your system is performing as expected. For example, you can create a CloudWatch alarm to monitor a specified metric and initiate an action (such as sending a notification to an email address) if the metric goes outside what you consider an acceptable range. 

## Device metrics


The `AWS/NetworkManager` namespace includes the following metrics for devices.


| Metric | Description | 
| --- | --- | 
|  DataIn | The number of bytes received by the device. | 
|  DataOut | The number of bytes sent by the device. | 
| TunnelDownCount | The number of VPN tunnels on the device that have a DOWN status. Static VPN tunnels with a DOWN status, and BGP VPN tunnels with any state other than ESTABLISHED, are included in the count. | 

## Metric dimensions for devices


To filter the metrics for your devices, use the following dimensions.


| Dimension | Description | 
| --- | --- | 
| DeviceId | Filters the metric data by the device. | 

## Link metrics


The `AWS/NetworkManager` namespace includes the following metrics for links.


| Metric | Description | 
| --- | --- | 
| DataIn | The number of bytes received by the on-premises network using this link. | 
| DataOut | The number of bytes sent from the on-premises network using this link. | 

## Metric dimensions for links


To filter the metrics for your links, use the following dimensions.


| Dimension | Description | 
| --- | --- | 
| LinkId | Filters the metric data by the link. | 

# View global network CloudWatch metrics


There are various options for viewing CloudWatch metrics for your global network, including the following:
+ Viewing metrics for the global network and filtering by transit gateway
+ Viewing metrics for a specific transit gateway and its attachments

**To view metrics for your global network and filter by transit gateway**

1. Open the Network Manager console at [https://console.aws.amazon.com/networkmanager/home/](https://console.aws.amazon.com/networkmanager/home).

1. In the navigation pane, choose **Global networks**, and choose the ID for your global network.

1. In the navigation pane, choose **Transit gateway network**.

1. Choose **Monitoring**. On this page, you can filter by transit gateway to view metrics for that transit gateway.

**To view metrics for a specific transit gateway and its attachments**

1. Open the Network Manager console at [https://console.aws.amazon.com/networkmanager/home/](https://console.aws.amazon.com/networkmanager/home).

1. In the navigation pane, choose **Global networks**, and choose the ID for your global network.

1. In the navigation pane, choose **Transit gateways**, and choose the ID for your transit gateway.

1. (Optional) Metrics and events use the default time set up in the CloudWatch Events event. To set a custom time frame, choose **Custom** and then choose a **Relative** or **Absolute** time, and then choose if you want to see that date range in **UTC** or the edge location's **Local time zone**.

   Choose **Add to dashboard** to add this metric to your CloudWatch dashboard. For more information about using CloudWatch dashboards, see [Using Amazon CloudWatch Dashboards](https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/CloudWatch_Dashboards.html) in the *Amazon CloudWatch User Guide*.
**Note**  
The **Add to dashboard** option only works if your registered transit gateway is in the US West (Oregon) Region.