# 8 AWS IoT Services


## 8.1 Device Defender


ExpressLink devices support the [AWS IoT Device Defender](https://docs.aws.amazon.com/iot/latest/developerguide/device-defender.html) service. They can publish a basic set of metrics to IoT Core at a configurable interval, including:


**Table 6 - ExpressLink Defender metrics**  

| ExpressLink Custom Metric | Type | Description | 
| --- | --- | --- | 
| Bytes Out | Count | Number of bytes sent since last update. | 
| Messages sent | Count | Number of messages sent since last update. | 
| Messages received | Count | Number of messages received since last update. | 
| Hard Reset Event | Flag | Set to 1 if a hardware reset occurred since last update. | 
| Reconnect Events | Flag | Set to 1 if a reconnect occurred since last update. | 
| Flash Memory Writes | Count | Number of writes to flash memory since last update. | 

All ExpressLink custom metrics are volatile in nature, as their values are reset to 0 after each periodic update (or set to 1 upon a device reset/reboot for the specific events). 

The device defender feature is activated by setting the *Defender* configuration parameter to a value greater than 0 in the configuration dictionary (using the AT\$1CONF command).

The Defender parameter value is used to indicate the number of seconds between successive updates of the Device Defender metrics. 

The Defender parameter is non-volatile so that an ExpressLink device resumes sending Device Defender metrics at the rate to which it was configured after any reset (soft command or hardware).

Examples:

```
AT+CONF Defender=0    # Device Defender metrics are disabled 
```

NOTE: This is the initialized value after a factory reset (see [Table 2 - Configuration Dictionary Persistent Keys](elpg-configuration-dictionary.md#elpg-table2)).

```
AT+CONF Defender=60      # Device Defender metrics will be sent every minute
AT+CONF Defender=3600    # Device Defender metrics will be sent every hour
```

### 8.1.1 DEFENDER: \$1not implemented in this version\$1


The DEFENDER command is reserved for use with the AWS IoT Device defender service.

## 8.2 AWS IoT Device Shadow


### 8.2.1 SHADOW: \$1not implemented in this version\$1


The SHADOW command is reserved for the support of the Device Shadow service.

## 8.3 AWS IoT JOBS


### 8.3.1 JOB: \$1not implemented in this version\$1


The JOB command is reserved for the support of the AWS IoT Jobs service.