How are ‘NetID’ and ‘Address Range’ settings used in OTAA

[Arty29]

Hello,

We are using the AEP version of the MultiConnect Conduit for LoRaWAN communications. In the “LoRa Network Server Configuration” window there are three parameters in the “Network” section for which that I do not properly understand their relationship to the LoRaWAN™ specification. These are:

‘NetID’, ‘Address Range Start’ and ‘Address Range End’

We tried the OTAA of an mDot end node using the following settings:

‘NetID’ = 0xA2FACE
‘Address Range Start’ = 0x400053C7
‘Address Range End’ = 0x40006000

After OTAA the console TRACE output from the mDot reported the following:
DevAddr = 0xDC0053C7
NetID = 0xDC0053

The DevAddr value appears to be derived from an address selected from the address range that is then ANDed with a value produced by taking the seven LSB of the (Conduit) ‘NetID’ parameter and shifting them left by 25 bits. The NetID value reported by the mDot does not match the value entered in the Conduit AES LoRa Configuration settings page.

According to the LoRaWAN™ specification section 6.1.1 the end-device address (DevAddr) is a 32 bit value composed of a 7 bit network identifier (NwkID) in the most significant bits and a 25 bit Network Address (NwkAddr) in the least significant bits.

From section 6.2.5 of the specification, NetID is a 24 bit field that is sent from the server to the end device in the Join-accept message. The most-significant 17 bits are a value freely chosen by the network operator and the least significant 7 bits are the NwkID that also forms part of the DevAddr.

It would seem that there are differences in the meaning of “NetID” as it is used in the conduit settings, the mDot trace and the LoRaWAN™ specification.

I would appreciate it if someone could help clarify how the conduit settings ‘NetID’, ‘Address Range Start’ and ‘Address Range End’ relate to the parameters that are generated during an OTAA join procedure.

Thank you.

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