I’m encountering a peculiar issue with downlink messaging on Mikrotik ltAp gateways using ChirpStack v4, and I’m hoping for some insights. The gateways are on the latest stable firmware (7.12).
The Situation:
Setup: Mikrotik ltAp gateways with UDP packet forwarder, running ChirpStack version v4.
Primary Issue: Devices can join the network and receive their initial downlink message without any trouble. However, all subsequent downlink messages get stuck in the queue.
Observations:
- Uplink communication works flawlessly.
- The first downlink post-joining is successful, but following that, no other downlinks are sent.
- This issue persists even after clearing device queues.
- The Mikrotik gateways appear online in ChirpStack, and regular stats are transmitted.
- This problem has been replicated on two different units in separate locations.
Additional Technical Detail:
I’ve been in touch with the ChirpStack team, and it was suggested that the issue might be related to the Mikrotik gateway’s handling of the TX_ACK message in the downlink process. It appears the gateways might not be using the correct token in the TX_ACK response, or not sending these packets at all, which is essential for ChirpStack to confirm the downlink transmission.
Has anyone experienced similar issues with downlinks on Mikrotik gateways, especially with firmware version 7.12?Are there specific configurations or settings in the Mikrotik firmware or packet-forwarder that could influence this behavior?
Any troubleshooting suggestions or insights related to the TX_ACK message handling would be incredibly valuable.