Downlink Queue Operations

The Things Stack keeps a queue of downlink messages per device. Applications can keep pushing downlink messages or replace the queue with a list of downlink messages.

You can schedule a downlink using the CLI, MQTT or HTTP webhooks.

To schedule downlinks using MQTT, see MQTT Server. To schedule downlinks using webhooks, see Scheduling Downlinks with Webhooks.

This guide shows how to interact with the downlink queue from the command-line interface (CLI).

If there are more application downlink messages in the queue, the Network Server sets the LoRaWAN FPending bit to indicate end devices that there is more downlinks available. In class A downlink, this typically triggers the device to send an uplink message to receive the downlink message. In class C, the Network Server automatically transmits all queued downlink messages.

Push and replace downlink queue

To push downlink to the end of the queue:

$ ttn-lw-cli end-devices downlink push app1 dev1 \
  --frm-payload 01020304 \
  --priority NORMAL \
  --f-port 42

You must pass an FPort with the --f-port flag. Confirmed downlinks can be set using --confirmed.

To replace the existing queue with a new item:

$ ttn-lw-cli end-devices downlink replace app1 dev1 \
  --frm-payload 01020304 \
  --priority NORMAL \
  --f-port 42

List queue

To see currently scheduled downlink messages:

$ ttn-lw-cli end-devices downlink list app1 dev1

Clear queue

To clear scheduled downlink messages:

$ ttn-lw-cli end-devices downlink clear app1 dev1