Class C downlink issue

Hello, I am having a problem with not getting the downlinks back from my end node. However, when it switches to Class A i do receive the downlink payload. From the LoRa server logs this is what I see for Class C as an example of when I trigger a downlink

Oct 12 12:11:39 raspberrypi loraserver[15556]: time="2018-10-12T12:11:39-07:00" level=info msg="finished unary call with code OK" grpc.code=OK grpc.method=GetNextDownlinkFCntForDevEUI grpc.service=ns.NetworkServerService grpc.start_time="2018-10-12T12:11:39-07:00" grpc.time_ms=3.457 peer.address="[::1]:38626" span.kind=server system=grpc Oct 12 12:11:39 raspberrypi loraserver[15556]: time="2018-10-12T12:11:39-07:00" level=info msg="device-queue item created" dev_eui=008000000000c265 f_cnt=23 Oct 12 12:11:39 raspberrypi loraserver[15556]: time="2018-10-12T12:11:39-07:00" level=info msg="finished unary call with code OK" grpc.code=OK grpc.method=CreateDeviceQueueItem grpc.service=ns.NetworkServerService grpc.start_time="2018-10-12T12:11:39-07:00" grpc.time_ms=14.554 peer.address="[::1]:38626" span.kind=server system=grpc Oct 12 12:11:39 raspberrypi loraserver[15556]: time="2018-10-12T12:11:39-07:00" level=info msg="device-queue deleted" id=47942 Oct 12 12:11:39 raspberrypi loraserver[15556]: time="2018-10-12T12:11:39-07:00" level=info msg="gateway/mqtt: publishing downlink frame" qos=0 topic=gateway/c0ee40ffff294325/tx Oct 12 12:11:39 raspberrypi loraserver[15556]: time="2018-10-12T12:11:39-07:00" level=info msg="device-session saved" dev_addr=0126f94d dev_eui=008000000000c265 Oct 12 12:11:42 raspberrypi loraserver[15556]: time="2018-10-12T12:11:42-07:00" level=info msg="gateway/mqtt: uplink frame received"

This is how loraserver looks like when it receives a downlink as a classA
Oct 12 12:04:35 raspberrypi loraserver[15556]: time="2018-10-12T12:04:35-07:00" level=info msg="rx info sent to network-controller" dev_eui=008000000000c265 Oct 12 12:04:35 raspberrypi loraserver[15556]: time="2018-10-12T12:04:35-07:00" level=info msg="device gateway rx-info meta-data saved" dev_eui=008000000000c265 Oct 12 12:04:35 raspberrypi loraserver[15556]: time="2018-10-12T12:04:35-07:00" level=info msg="device-session saved" dev_addr=0126f94d dev_eui=008000000000c265 Oct 12 12:04:35 raspberrypi loraserver[15556]: time="2018-10-12T12:04:35-07:00" level=info msg="finished client unary call" grpc.code=OK grpc.method=HandleUplinkData grpc.service=as.ApplicationServerService grpc.time_ms=27.831 span.kind=client system=grpc Oct 12 12:04:35 raspberrypi loraserver[15556]: time="2018-10-12T12:04:35-07:00" level=info msg="finished unary call with code OK" grpc.code=OK grpc.method=GetNextDownlinkFCntForDevEUI grpc.service=ns.NetworkServerService grpc.start_time="2018-10-12T12:04:35-07:00" grpc.time_ms=3.316 peer.address="[::1]:38626" span.kind=server system=grpc Oct 12 12:04:35 raspberrypi loraserver[15556]: time="2018-10-12T12:04:35-07:00" level=info msg="device-queue item created" dev_eui=008000000000c265 f_cnt=13 Oct 12 12:04:35 raspberrypi loraserver[15556]: time="2018-10-12T12:04:35-07:00" level=info msg="finished unary call with code OK" grpc.code=OK grpc.method=CreateDeviceQueueItem grpc.service=ns.NetworkServerService grpc.start_time="2018-10-12T12:04:35-07:00" grpc.time_ms=12.382 peer.address="[::1]:38626" span.kind=server system=grpc Oct 12 12:04:35 raspberrypi loraserver[15556]: time="2018-10-12T12:04:35-07:00" level=info msg="device-queue deleted" id=47934 Oct 12 12:04:35 raspberrypi loraserver[15556]: time="2018-10-12T12:04:35-07:00" level=info msg="gateway/mqtt: publishing downlink frame" qos=0 topic=gateway/c0ee40ffff294325/tx Oct 12 12:04:35 raspberrypi loraserver[15556]: time="2018-10-12T12:04:35-07:00" level=info msg="device-session saved" dev_addr=0126f94d dev_eui=008000000000c265 Oct 12 12:04:35 raspberrypi loraserver[15556]: time="2018-10-12T12:04:35-07:00" level=info msg="**downlink-frames saved**" dev_eui=008000000000c265 token=54489 Oct 12 12:04:37 raspberrypi loraserver[15556]: time="2018-10-12T12:04:37-07:00" level=info msg="gateway/mqtt: uplink frame received"

I notice one difference between these two is that with class C i never get a message of downlink-frames saved but with Class A I do get that message. Not sure if maybe that could be the reason why I do not receive the downlink payload for Class C. If that is the problem, how would I go about it? I would like to know why this is occurring. I have been struggling with this issue for a week so any clues to this would be very appreciated.

Also to note, I have updated my LoRa Server with the latest update 2.3.0 as of today.

Did you ever solve this?

Yes I solved it. It was a bug from my code for class C so it works correctly now.

Hi jessica, could you help me to send downlink from gateway to my end device (Lora on Arduiuno). I’m using IC880A and RFM96

Cool jessica! is this issue fixed in the current release?
I am having a similar issue… It seams as the class C protocol is not implementd correctly… either there is no delay between the receive and send events or there is too much of it… Can you help by posting your fix? tks!