Class C device adding confirm downlink to queue


I am sending confirmed downlink to my Class C device But server is adding confirm downlink to Downlink queue .

Currently Using -

chirpstack-application-server version - 3.7.0-1-g6a9c690
chirpstack-network-server version - 3.6.0-2-g1d66d30
chirpstack-gateway-bridge version - 3.6.0

Device profile configuration - Class C, RX2 data-rate - 3, LoRaWAN MAC version - 1.0.1, LoRaWAN Regional Parameters revision - A

I’m facing this problem on my different chirpstack server versions which was working fine before and I did not made any changes. Now I have successfully restarted all services yet still facing the same issue.

Please Guide.


@brocaar please help.

Hi, I am facing same problem.
Only difference is, that I use OTAA.

Whenever I want to make a downlink, it will be scheduled.
On next regular uplink, downlink will be send.

Any help or hints would we great!


Hi. I am facing the same problem. Is there really no solution?

Hi, still have the problem.

Maybe some further questions (from Device-classes - ChirpStack open-source LoRaWAN® Network Server

  1. “ChirpStack Network Server supports Class-C devices and uses the same Class-A downlink device-queue for Class-C downlink transmissions.”
    Does that mean, that a downlink like a normal confirm also goes in the queue? Or is the queue exclusive only for triggered downlinks?

  2. “[…] Until the frame has timed out, ChirpStack Network Server will wait with the transmission of the next downlink Class-C payload.”
    I assume it is per device, right? So, if I would have x devices and sending downlinks to every device, than chirpstack will not wait for response or timeout from one device and all other have to wait for it, right?

We still have the challenge that our Class-C device Downlink commands stuck in queue around 2 minutes. Currently I have no idea how to investigate the behaviour. All our Class-C devices facing the same issue.
Can anybody help?