3 - Receiving Messages
Messages sent from a network server to an end device are referred to as downlinks. These are sent to the end device via a single gateway. If there are multiple gateways near a device, the network server will select the most suitable gateway to broadcast from. This means the end device does not need to consider de-duping.
Devices operating in Class A mode only receive downlinks during the receive windows opened following an uplink, as described in the section Opening Receive Windows of the Sending Messages Book.
Devices that support Class B mode as well as Class A can receive additional downlinks in receive windows opened at fixed time slots. Read more about Class B mode in the Class B Book.
Devices that support Class C mode as well as Class A can receive additional downlinks at any time. Read more in the Class C: Continuously Listening for Downlinks book.
Todo
Fix link
In this book, you learn how to receive and handle downlink packets using the LoRaWAN® 1.0.4 specification.
Processing the Downlink Packet
Process the MAC Commands
If MAC commands were found in both the FOpts field and the FRMPayload field, then the entire message must be ignored; it is not LoRaWAN® compliant to include MAC commands in both fields.
If no MAC commands were found, proceed to the next section Process the Application Data.
If MAC commands were found, they must be processed, as described in the upcoming section Handling MAC Commands.