nRF93M1-DK – No data connectivity over USB RNDIS/CDC-ECM

[packetmoose]

I'm trying to establish a data connection from a Linux host through the USB network interface of an nRF93M1-DK.

The modem registers successfully on the cellular network, the PDP context is active, and AT%PING works over the modem's UART interface.

The USB Ethernet interface is detected correctly by Linux using the rndis_host driver and reports UP,LOWER_UP. However, no data is received from the modem.

Tests performed:

• DHCP: Discover packets transmitted, but no response.

• Static IP: Manually configured the IP address obtained from the PDP context, without success.

• USB modes: Tested both RNDIS (usbNet=0) and CDC-ECM (usbNet=1) with identical results.

• Firmware: Tested versions 1.4.1 and 1.5.0.

• Packet capture: Confirmed correctly formatted DHCP Discover packets are transmitted over USB, with successful bulk OUT transfers (URB status = 0).

• RX/TX counters: TX increments, but RX remains at zero.

Modem configuration:

• APN: services.telenor.se

• PDP context: Active (AT+CGACT? returns 1,1)

• USB control: usbCtrl=0

Questions:

1. Is any additional AT command or configuration required to enable data forwarding between the PDP context and USB RNDIS/ECM?

2. Is the modem expected to provide DHCP over USB, or is static IP configuration required?

3. Is this a known issue with the current firmware?

Any guidance on the expected USB networking setup would be appreciated.

Thank you,

[Maria Gilje]

Hello, 

It seems like the step to bind the network device to the PDN is missing: 

> AT%NETDEVCTL=3,1,1

OK
%NETDEVCTL: 1

Let me know if that AT command helps to get the data connectivity up and running. If not, I'll get some input from someone with more experience on this topic. 

Best regards,

Maria

[packetmoose]

Thank you, that was the missing piece!

Is there any documentation of what the different parameters to  AT%NETDEVCTL means?

Best Regards,