nRF9160 disconnects after 4-5 minutes when keep alive time is 60

[Nikunj]

Hello Nordic Semiconductor,

I connected my nRF9160 with my MQTT broker. My MQTT client as well as broker's keep alive time is 60.

MQTT client connection disconnects after 4-5 minutes with POLLNVAL error.

My application needs MQTT connection always with device which isn't there somehow.

Thanks,

Nikunj

[Håkon Alseth]

Hi,

 

Q1: How is your signal strength? It can be checked using this AT command: https://infocenter.nordicsemi.com/topic/ref_at_commands/REF/at_commands/mob_termination_ctrl_status/cesq_set.html?cp=2_1_3_4_0

Q2: Is this on a development kit or a custom board?

Q3: Is the behavior consistent, or can it sometimes take hours before the disconnect occurs?

Q4: What checkout of "nrf" are you using?

 

Kind regards,

Håkon

[Nikunj]

Hello Hakon,

Thanks for reply.

1. Signal strength is good in my area I can connect with MQTT as well as send data also.

2. This is on development kit of nRF9160 pca_0.8.5 hardware

3. This behavior is consistent, it disconnects after 3-4 minutes.

4.  I am using nRF9160 SICA BAA version chip.

Thanks,

Nikunj

[Håkon Alseth]

Hi,

 

What is the output of CESQ at command?

Are you running the latest modem fw, v1.0.1?

Which tag of the NCS SDK are you using?

 

Kind regards,

Håkon

[Nikunj]

Hello,

Output of CESQ command is,

AT+CESQ
+CESQ: 99,99,255,255,255,57
OK

Yes, I am using latest modem firmware v1.0.1 for dk 

Tag of my ncs SDK is v1.0.0,

Regards,

Nikunj

[Håkon Alseth]

Hi Nikunj,

 

I am unable to reproduce this with the standard mqtt_simple sample. If you for instance connect to mqtt.eclipse.org (see this line: https://github.com/NordicPlayground/fw-nrfconnect-nrf/blob/master/samples/nrf9160/mqtt_simple/prj.conf#L34), are you then able to reproduce the issue?

Is there any TLS used? Are you connecting to a public mqtt server, or is it your own server?

 

Kind regards,

Håkon

[Nikunj]

Hi Hakon,

I do connect with own server not with mqtt.eclipse.org.

There is no TLS used in it.

I Need configuration as like,

Connect to MQTT broker --> send data --> to MQTT broker 

But every time I got POLLNVAL error.

Thanks,

Nikunj

[Håkon Alseth]

Hi Nikunj,

 

Could you try connecting to mqtt.eclipse.org and see if this also behaves similar?

You could try to adjust the keep-alive and check what happens then.

 

Kind regards,

Håkon