Export data to Message Queue

Configure data export

1. Log on to the Alibaba Cloud Link WAN console.
2. In the left navigation pane, select Node Management > Node Group, and click Data Forwarding in the Actions column for the target node group.
3. In the Data Forwarding Settings dialog box, configure data forwarding as shown in the following figure.

   After the configuration is complete, subscribe to a topic in MQ to receive uplink data. For more information, see Message Queue for Apache RocketMQ.

   Newer versions of Link WAN no longer support sending downlink data through topics. This feature is available only to users of earlier versions. Instead, use API operations to send downlink data because this method provides more response information from the core network. For more information, see SendUnicastCommand.

   Note To accelerate your development, you can obtain the SDK with encapsulated API operations from the Java SDK usage guide.

   The data is exported in JSON format. The content is as follows:

   Field	Type	Description
   data	string	Uplink data message. A hexadecimal string.
   fport	int	Service port number.
   snr	double	Uplink signal-to-noise ratio (SNR).
   rssi	int	Uplink signal strength.
   joinEui	string	Application identifier.
   devAddr	string	Device address.
   devEui	string	Device identifier.
   gwEui	string	Gateway ID.
   time	long	Timestamp in milliseconds.
   datr	string	Spreading factor.
   mtype	int	Message type: 0: join 2: unconfirmed up 4: confirmed up
   fcnt	long	Uplink frame count.

   The following code provides an example:

   {
       "data": "aa1fc800003710ff0005d769ffff00014100ffffffffffffffffffffffffff5b",
       "datr": "SF12BW125",
       "devAddr": "xxxx",
       "devEui": "xxxxxx",
       "fcnt": 1123,
       "fport": 99,
       "gwEui": "xxxxxx",
       "joinEui": "xxxxxxx",
       "mtype": 2,
       "rssi": -106,
       "snr": -17.0,
       "time": 1541412741702
   }                   

Downlink data from MQ

The following code provides an example:

{
    "data": "aa1fc800003710ff0005d769ffff00014100ffffffffffffffffffffffffff5b",
    "devEui": "xxxx",
    "fport": 99,
    "confirmed": true,
    "maxRetries": 0
}