In a LoRaWAN network that uses the ABP (Activation By Personalization) activation method, if I register a node (device) with a certain DevEUI and DevAddr, along with the other necessary parameters (NwkSKey, AppSKey). If I later delete this node and try to register it again, keeping the same DevAddr, but changing the DevEUI, would there be any synchronization problem or other inconsistency in the network?
I did quick test on TTN using latest RUI3 v4.2.1.
If you created a new device with new DEVEUI but with same DEVADDR, NWKSKEY and APPSKEY, your uplink will go to the newly created device.
I did a test with chirpStak, I also noticed this behavior, so couldn’t it harm the network, I mean losing FCnt?
FCnt is used to protect for replay attacks. This is specially true for ABP were session keys do not change even on reset because there is no re-join. I do not think it is harmful to the network. But there is security compromise on the device.