Receiving data from KPN network


My TTN gateway receives a lot of data from the Dutch KPN network and I am curious if I can trace who is the sender or otherwise analyze the data. I would also like to know if it is normal for data from KPN network to be received by a TTN gateway. Someone more experienced with this?

Regards, Hans.


LoRaWAN is a broadcast protocol where every gateway in range receives every nodes transmission. As a result your gateway receives data from nodes provisioned on the KPN network.
Because all LoRaWAN data is encrypted using AES128 chances of decrypting and analyzing it are slim to non existing if you do not have access to the nodes unique keys.

The only way to trace the sender would be to try and find its location using an directional antenna and some radio equipment. Or with multiple gateways, signal strengths, calculations and some luck.

Thanks for your clear explanation Jac, now I understand what is happening. Although I do not doubt your explanation I do wonder why the technology in a gateway is not smart enough to filter such messages. Now they are forwarded to the TTN servers and use unnecessary bandwidth.

And I know which node sends the messages, it’s from an underground waste container that reports when it is full.

The current generation is dumb on purpose. The reference software and the network don’t contain any means to manage which packets should be forwarded. The next generation software provided by Semtech provides the means to remotely configure the packet forwarder enabling setting the filters from a central location.
If roaming for LoRaWAN ever takes of we need a way to control filtering to set which packets should be forwarded and which should not.

BTW, the bandwidth used is minimal, the average LoRaWAN packet including overhead should be well below 100 bytes on the wire.

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Maybe a sort of blacklist which blocks from non-TTN messages in the future :wink:

It is ironic that the server appears to accept messages that if continuously sent at the rate indicated are 44 times the fair access limit that TTN users need to keep to as well as at a duty cycle of 1.5%.

That is the reality of using a shared medium like radio spectrum.