Wifi/BLE Paxcounter Project with ESP32 boards

[arjanvanb (Arjan)]

@Amedee

I was expecting to see a packet counter roll-over at 64K, but is still counts up…

As an aside, if you really expected the counter to rollover:

@arjanvanb

In LoRaWAN 1.0.x, the value of FCnt only holds the 16 least-significant bits (LSB) of the actual frame counter. But for a 32 bits frame counter still all 32 bits are used when calculating the MIC. So, the server needs to guess or try the other 16 bits when validating the MIC. The server can use its own internal counters for a best guess. And due to the maximum allowed gap between the last known value and current value, the server needs to try, and will try, only one additional value for the MSB.