Frame pending messages

Byte 0	Byte 1
Type=0x00	ACK

When additional messages are available on a LoRaWAN gateway, this uplink message is sent to trigger the gateway to send downlinks that are queued (if no other messages are pending).

ACK: Acknowledge token. Refer the section Acknowledge token for more details.

Notes

1. To shorten the payload, this message is only 2 Bytes long (no common header).
2. Some network operators may not support the downlink available indication in LoRaWAN downlinks.