Sodaq SARA aff R410M: MQTT over LTE-M (KPN)

Hello everyone,

I’ve been trying to get a SARA aff R410M to do MQTT over the KPN LTE-M network and it’s not working.

I’m using the SODAQ_R4X library with the mqtt_test sketch. I’ve set the APN for KPN (ltem.internet.m2m) and to be sure I’ve added the power pins for the radio to the sketch.

As far as I can tell the module has no problem connecting to the network but fails at logging in to the MQTT server.

I have tried the Mosquitto test sever as wel as a local server. I have enabled the debug output from the library and I will post a log at the end of this post.

I hope I’m just overlooking something small here. If anyone has an idea I’m happy to try it out.

greetings,
Anton Stamhuis

DEBUG LOG*****

15:38:40.013 -> Booting up…
15:38:40.013 -> [init] started.
15:38:40.013 -> [initBuffer]
15:38:42.009 -> >> AT
15:38:42.009 -> << timed out
15:38:42.514 -> >> AT
15:38:42.514 -> << timed out
15:38:43.027 -> >> AT
15:38:43.027 -> << timed out
15:38:43.504 -> >> AT
15:38:43.504 -> << timed out
15:38:44.016 -> >> AT
15:38:44.016 -> << AT
15:38:44.290 -> << OK
15:38:45.550 -> << timed out
15:38:45.550 -> >> AT+CMEE=2
15:38:45.550 -> << AT+CMEE=2
15:38:45.550 -> << OK
15:38:45.550 -> >> ATE0
15:38:45.550 -> << ATE0
15:38:45.550 -> << OK
15:38:45.550 -> >> AT+CFUN?
15:38:45.550 -> << +CFUN: 1
15:38:45.550 -> << OK
15:38:45.550 -> >> AT+COPS?
15:38:45.550 -> << +COPS: 0
15:38:45.550 -> << OK
15:38:45.550 -> >> AT+URAT?
15:38:45.550 -> << +URAT: 7
15:38:45.550 -> << OK
15:38:45.550 -> >> AT+CGDCONT?
15:38:45.550 -> << +CGDCONT: 1,“IP”,“ltem.internet.m2m”,“0.0.0.0”,0,0,0,0
15:38:45.585 -> << OK
15:38:45.585 -> >> AT+CSQ
15:38:45.585 -> << +CSQ: 99,99
15:38:45.585 -> << OK
15:38:46.064 -> >> AT+CSQ
15:38:46.064 -> << +CSQ: 99,99
15:38:46.098 -> << OK
15:38:47.599 -> >> AT+CSQ
15:38:47.599 -> << +CSQ: 99,99
15:38:47.599 -> << OK
15:38:50.090 -> >> AT+CSQ
15:38:50.090 -> << +CSQ: 99,99
15:38:50.090 -> << OK
15:38:53.605 -> >> AT+CSQ
15:38:53.605 -> << +CSQ: 26,99
15:38:53.605 -> << OK
15:38:53.605 -> >> AT+CGATT?
15:38:53.605 -> << +CGATT: 1
15:38:53.605 -> << OK
15:38:53.605 -> >> AT+CGDCONT?
15:38:53.605 -> << +CGDCONT: 1,“IP”,“ltem.internet.m2m”,“10.35.184.203”,0,0,0,0
15:38:53.639 -> << OK
15:38:53.639 -> >> AT+UDCONF=1,1
15:38:53.639 -> << OK
15:38:53.639 -> >> AT+CPIN?
15:38:53.639 -> << +CPIN: READY
15:38:53.639 -> << OK
15:38:53.639 -> Network connected
15:38:53.639 -> >> AT+UMQTT=2,“test.mosquitto.org”,1883
15:38:53.639 -> <<
15:38:53.639 -> << +UMQTT: 2,1
15:38:53.639 -> << OK
15:38:53.639 -> >> AT+UMQTTC=1
15:38:53.639 -> <<
15:39:01.778 -> << +UMQTTC: 1,1
15:39:01.778 -> << OK
15:41:53.584 -> MQTT failed
15:41:53.584 -> Setup done


Hey Anton!

I think you need to solder the 0 ohm resistor here to receive URC’s.

Regards,
Jan

It could also be a problem with the MTU size of the r410 on KPN network.

I had problems with larger payloads since MTU size was at 68 bytes in Sweden. This was using UDP but since it was a problem with NAT it might still be a problem using MQTT and TCP.

I read in a test report that this problem also was on KPN LTE-M network

https://attachments-eu-west-1.insided.com/5fe1cb1d-2572-47b8-a486-130cecabe8d5/Test%20results%20LTE-M%20devices%20v1.0.pdf

Thx. everyone! I got MQTT working now, soldering the jumper did the trick.

I thought I would get to this sooner but better late then never.

@Krolken It seems that MTU size wasn’t an issue this time. But thanks anyway for your trouble. :sweat_smile:

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