How does the ChirpStack Packet Multiplexer work?

From my understanding, 1 gateway forward packet to ChirpStack server. Then Multiplxer in ChirpStack server till forwad the payload to more than 1 network server, am I right?

Probably it’s only good for development/debug purposes? Or could it be used for fail-over/redundancy somehow?
It only works good when the activation parameters are the same. But I guess even two ChirpStack instances will use use/give a different random number and device address on a JoinReq.
Perhaps you can synchronise those settings using the API.
Persistent activation on the nodes would be helpful in this case I think?

For completeness of the context, you will find most information here: https://github.com/brocaar/chirpstack-packet-multiplexer/.

The Semtech UDP Packet Forwarder forwards to the ChirpStack Packet Multiplexer, which then can forward to multiple LoRaWAN Network Servers (in the UDP format). Information is forwarded as is, so each configured backend will receive the same data.

One reason why the multiplexer can be useful is when you want to forward data to multiple network servers, e.g. a production environment and testing. Or when you want to forward to TTN and ChirpStack, …

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Well, the story as below. Sorry. I still newbie and learning stage.

  1. I subscribe to IoT-in-a-Box. I couldn’t send downlink payload to trigger my Netvox R602A (Siren) when Temperature sensor (R718AB) out of specification. It seem IoT-in-a-Box don’t allow me to do so. I have no access to their TTN also.
  2. Therefore, I’m thinking if I can have single gateway with multiplexer to TTN (connect to IoT-in-a-Box) and ChirpStack (to send downlink payload to Siren).

Yes. I notice this feature. I not sure where is the configuration link path to add both server address (TTN and Chirpstack) as I’m using docker.
https://www.chirpstack.io/guides/docker-compose/

Dear all,

I am discovering and testing chirpstack. Sorry if my question is a newby question.

I would like to use a multiplexer for redundancy, sending messages to several independant servers.

I implemented the chirpstack multiplexer and I have two servers receiving my messages (controled with Wireshark) and both servers can see join requests.
One of the server controls OTAA activation.
But I do not understand how the messages could be exploited on the second network server, espcially because of encryption.
Is there a way to bypass this pb ?

Thanks a lot

Best regards.

Dubs