The MQTT Sensor Network standard provides a lightweight networking protocol perfectly suited to low cost, low power hardware. The protocol allows using small topic identifiers in place of the full topic name when sending and receiving publish data.
The wolfMQTT SN Client implementation is based on the OASIS MQTT-SN v1.2 specification. The SN API is configured with the
--enable-sn option. There is a separate API for the sensor network API, which all begin with the "SN_" prefix. The wolfMQTT SN Client operates over UDP, which is distinct from the wolfMQTT clients that use TCP. The following features are supported by the wolfMQTT SN Client:
- Will topic and message set up
- Will topic and message update
- All QoS levels
- Variable-sized packet length field