Devices get disconnected after some period of gateway breakdown

ChirpStack Application Server
1

I have an issue with devices that were connected over a gateway which got offline for a while (3 months).
After the gateway came back online, the devices now show “This device has not (yet) been activated” in the activation menu. Before the gateway interruption, the data packets from the nodes were recieved without an issue.
Looking at the the live LoRaWAN frames in the gateway, regular uplinks are recieved from the lost devices.

Has anybody an idea what the reason might be for the loss of the activation keys?

Regards,
Pascal

2

This is intended behaviour, Chirpstack removes the device session keys from the database after a certain amount of time inactive (I assume simply for space management). I know there is a configuration setting to change how long they are stored before deleting although I have never done it myself.

You could try searching the chirpstack.toml configuration options, or maybe someone else can speak to the actual setting.

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3

ChirpStack v3 had this as configuration option device_session_ttl:

It appears that v4 has it as an option as well, but it is not documented on the configuration page. Source is here:

I would give that a try.

4

It is no longer documented since v4.7 moves the sessions to PostgreSQL and these sessions will no longer expire after x time.

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5

Makes sense. Sounds like the user could either use that setting or should upgrade.

6

Thanks for your comments. Being still on v3, I’ll increase the device_sessin_ttl parameter to prevent future problems.
The nodes I’m missing are rather old (LoRaWAN v1.0.1) and don’t initiate an automatic rejoin when lost. So all that remains to me is to reboot each node…

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7

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