Behavioural question of the keepalivetimeout in mqtt

[Srini-Zoetis]

Hi Team, I was performing an exercise using the telemetry sample code in iothub_client where i have made the following changes and the observed behavior is as follows. I have a query regarding this observation.

• Modified the iothub_client_ll_telemetry_sample code to send once a message to iothub and wait every 10mins (keepalivetimeout) before sending a ping request. I observed that after no activity for 45mins, the connection gets disconnected and reconnected (since i keep the do_work function alive indefinitely)
• Next time i kept the keepalivetimeout value to 60mins before it sent PINGREQ,PINGRESP, and exactly at 30th min it disconnected and reconnected.

I want to understand who/where is it decided to wait for 30mins/ 45mins based on the keep alive timeout. And what is the max time out that is allowed before the system disconnects from iothub when there is no network activity.

thanks Srinikethan

[danewalton]

Hi @Srini-Zoetis We have documentation here which hopefully will clarify how this behavior works. Please let us know if this helps.

[ericwolz]

The default keepalive is configured for optimal performance on your platform. Is there a reason you need to modify it from the default?

[danewalton]

Closing this issue for now due to inactivity. If you would like it reopened, please let us know. For any other questions, please open another Github issue.