Subscribing and Publishing MQTT Messages from Gateway(Semtech Packet Forwarder Protocol)

Links to Documentation

Subscribing to MQTT Messages from the device

• MQTT Command to view UPLINK Messages

• mosquitto_sub -v -t lora/<enter-DEV-EUI-here>/up -u <Enter_Username_if_any> -P <Enter_Password_if_any>

• Example

• mosquitto_sub -v -t lora/30-37-37-35-60-31-5f-0f/up -u User -P top_secret_password

• Response

• lora/30-37-37-35-60-31-5f-0f/up
  {
     "tmst":1670771435,
     "chan":0,
     "rfch":0,
     "freq":868.1,
     "stat":1,
     "modu":"LORA",
     "datr":"SF7BW125",
     "codr":"4/5",
     "lsnr":10.2,
     "rssi":-27,
     "opts":"",
     "size":11,
     "fcnt":8,
     "cls":0,
     "port":1,
     "mhdr":"40d1c4fd00000800",
     "data":"ADk/c3MAfy4AEiY=",
     "appeui":"31-20-03-21-ec-61-07-00",
     "deveui":"30-37-37-35-60-31-5f-0f",
     "devaddr":"00fdc4d1",
     "ack":false,
     "adr":false,
     "gweui":"00-80-00-00-00-01-8c-8a",
     "seqn":8,
     "time":"2023-06-09T11:56:16.293904Z"
  }
  

• The "data" field contains the uplink data in Base64 format.

  • "data" : "ADk/c3MAfy4AEiY="

• Paste the Base64 Payload into the Excel Tool MLR003 Payload Encoder/Decoder

• (Uplink Decoder Sheet) and Click Convert to view the decoded messages

• The Excel decoder output will be as follows

Publishing MQTT Messages to the Device

• MQTT Command to send Downlink messages to the device

• Use the Excel Tool to prepare the Base64 Payload for the Downlink from “Downlink Encoder“ Tab MLR003 Payload Encoder/Decoder

• Example Downlink Payload

• 

  SQAoAABA

• mosquitto_pub -t lora/<enter_DEV_EUI_here>/down -m '{"data":<enter_Base64_payload_here>,"port":1}' -u <enter_Username> -P <enter_Password>

• Example

• mosquitto_pub -t lora/30-37-37-35-60-31-5f-0f/down -m '{"data":"SQAoAABA","port":1}' -u User -P top_secret_password