# AWS Transit Gateway Monitoring

## AWS Transit Gateway - An Overview

Amazon Transit Gateway is a fully managed service that enables customers to connect Virtual Private Clouds (VPCs) and on-premises networks through a central hub. It simplifies complex network topologies by acting as a scalable, high-performance transit layer for routing traffic between networks. Additionally, it supports key features such as bandwidth control, route propagation, and inter-region peering.

## Creating a new AWS Transit Gateway monitor

To learn how to create a new AWS Transit Gateway monitor, [refer here](https://www.manageengine.com/products/applications_manager/help/aws-monitoring-tools.html#NewMonitor).

## Monitored Parameters

Go to the **Monitors Category** **View** by clicking the Monitors tab. Click on **Transit Gateway** from the 'Child Monitors' under the **Cloud Apps** table. The bulk configuration view is displayed, distributed into three tabs:

- **Availability** tab gives the Availability history for the past 24 hours or 30 days.
- **Performance** tab gives the Health Status and events for the past 24 hours or 30 days.
- **List view** enables you to perform [bulk admin configurations](https://www.manageengine.com/products/applications_manager/help/bulk-config.html).

Click on the monitor name to see all the **Amazon Transit Gateway** metrics listed under the following tabs:

- [Performance Overview](https://www.manageengine.com/products/applications_manager/help/aws-transit-gateway-monitoring-tools.html#Overview)
- [Attachments](https://www.manageengine.com/products/applications_manager/help/aws-transit-gateway-monitoring-tools.html#Attachments)
- [Connects](https://www.manageengine.com/products/applications_manager/help/aws-transit-gateway-monitoring-tools.html#Connects)
- [Configuration](https://www.manageengine.com/products/applications_manager/help/aws-transit-gateway-monitoring-tools.html#Configuration)

### Performance Overview

| Parameter | Description |
|---|---|
| **STATUS INFORMATION** |  |
| State | The state of the transit gateway. |
| **DATA RECEIVED** |  |
| Rate of Data Received | The total amount of data received per second by the transit gateway between poll intervals (in MB/s). |
| Data Received | The total amount of data received by the transit gateway between the poll intervals (in MB). |
| **DATA SENT** |  |
| Rate of Data Sent | The total amount of data sent per second from the transit gateway between poll intervals (in MB/s). |
| Data Sent | The total amount of data sent from the transit gateway between the poll intervals (in MB). |
| **PACKETS RECEIVED** |  |
| Rate of Packets Received | The total number of packets received per second by the transit gateway during the poll interval (in packets/s). |
| Packets Received | The total number of packets received by the transit gateway between the poll interval. |
| **PACKETS SENT** |  |
| Rate of Packets Sent | The total number of packets sent per second by the transit gateway between the poll interval (in packets/s). |
| Packets Sent | The total number of packets sent by the transit gateway between poll intervals. |
| **BYTES DROPPED** |  |
| Bytes Dropped - Blackhole Route | The total number of bytes dropped because they matched a blackhole route between poll intervals. |
| Bytes Dropped - No Route | The total number of data packets dropped because they did not match any route between poll intervals. |
| **PACKETS DROPPED** |  |
| Packets Dropped - Blackhole Route | The total number of packets dropped because they matched a blackhole route between poll intervals. |
| Packets Dropped - No Route | The total number of packets dropped because they did not match any route during the poll interval. |
| **PACKETS DROPPED - TTL EXPIRED** |  |
| Packets Dropped - TTL Expired | The total number of packets dropped because the TTL (Time To Live) expired between poll intervals. |

### Attachments

| Parameter | Description |
|---|---|
| **Transit Gateway Attachments** |  |
| Attachment ID | The unique identifier of the transit gateway attachment. |
| Attachment Name | The name of the transit gateway attachment, if configured using the Name tag in the AWS portal. |
| Attachment State | The current operational state of the transit gateway attachment. |
| Resource Type | The type of the resource attached to the transit gateway. **Possible values:** vpc \| vpn \| direct-connect-gateway \| peering \| connect \| tgw-peering |
| Resource ID | The unique identifier of the resource attached to the transit gateway. |
| Route Table Association State | The state of the route table association. **Possible values:** Associating \| Associated \| Disassociating \| Disassociated |
| Route Table ID | The unique identifier of the route table associated with the transit gateway attachment. |
| Creation Time | The timestamp shows when the transit gateway attachment was created. |

### Connects

The Connects tab displays monitoring data for Connect-type attachments and their associated Connect peers configured in the transit gateway.

**Note:** Data collection for **Transit Gateway Connects** is disabled by default. To enable/disable data collection, navigate to **Settings** > **Performance Polling**. In the **Optimize Data Collection** tab, select **Amazon Transit Gateway** as the Monitor Type, choose **Transit Gateway Connects** as the Metric Name, and update the Default Polling Status as required.

| Parameter | Description |
|---|---|
| Number of Connect Attachments | The total number of Connect attachments associated with the transit gateway. |
| Number of Connect Peers | The total number of Connect peers associated with the transit gateway. |
| **CONNECT ATTACHMENTS** |  |
| Connect Attachment ID | The unique identifier of the Transit Gateway Connect attachment. |
| Name | The user-defined name of the Transit Gateway Connect attachment. |
| Transport Attachment ID | The identifier of the underlying Transit Gateway attachment on which the Connect attachment was created. |
| Creation Time | The date and time when the Transit Gateway Connect attachment was created. |
| Connect Peer Count | The total number of Connect peers associated with the Connect attachment. |
| Connect Peer Down Rate | The percentage of Connect peers associated with the attachment that are in a down state (in %). |
| Connect Attachment State | The current lifecycle state of the Transit Gateway Connect attachment. |
| **CONNECT ATTACHMENT PEERS** |  |
| Connect Peer ID | The unique identifier of the Transit Gateway Connect peer. |
| Name | The user-defined name of the Transit Gateway Connect peer. |
| Creation Time | The date and time when the Transit Gateway Connect peer was created. |
| TGW GRE Address | The GRE tunnel IP address assigned to the Transit Gateway side of the Connect peer. |
| Peer GRE Address | The GRE tunnel IP address assigned to the peer side of the Connect peer. |
| BGP Session Count | The total number of BGP sessions configured for the Connect peer. |
| BGP Session Down Rate | The percentage of BGP sessions for the Connect peer that are currently in the down state (%). |
| Peer State | The current lifecycle state of the Transit Gateway Connect peer. |
| **PERFORMANCE CHARTS** |  |
| Top 5 Connect Peers by BGP Session Count | Displays the top 5 Connect peers by the total number of BGP sessions between the poll intervals. |
| Top 5 Connect Peers by BGP Session Down Rate | Displays the top 5 Connect peers by the percentage of BGP sessions in a down state between the poll intervals. |

### Configuration

| Parameter | Description |
|---|---|
| **CONFIGURATION** |  |
| Transit Gateway ID | The ID of the transit gateway, if configured using the Name tag in the AWS portal. |
| Description | The description of the transit gateway. |
| Creation Time | The creation time of the transit gateway. |
| Association Route Table ID | The ID of the default association route table. |
| Propagation Route Table ID | The ID of the default propagation route table. |
| Amazon ASN | A private Autonomous System Number (ASN) for the Amazon side of a BGP session. |
| **ADVANCED SETTINGS** |  |
| Association Route Table | Indicates whether resource attachments are automatically associated with the default association route table. |
| Propagation Route Table | Indicates whether resource attachments automatically propagate routes to the default propagation route table. |
| Security Group Referencing Support | Indicates whether referencing security groups across VPCs attached to the transit gateway is allowed. |
| DNS Support | Indicates whether DNS support is enabled. |
| VPN ECMP Support | Indicates whether Equal Cost Multipath Protocol (ECMP) support is enabled. |
| Multicast Support | Indicates whether multicast is enabled on the transit gateway. |
| Auto Accept Shared Attachments | Indicates whether attachment requests from other AWS accounts are automatically accepted. |