nRF9160 lte passthrough

[fe-hadella]

We are using a custom ARM board which runs Linux and has a UART interface to a nRF9160. 

I'm not how to phrase this exactly so I will just describe what I would like to do. Our goal is to use GPS to access position data and to also update various Linux packages over the LTE interface. We are looking at this cloud service called Mender which can deploy .deb files to a set of devices. This requires TLS to be enabled on the nRF9160 -- Mender requires TLS. I've been able to use this service for devices with Ethernet access - can LTE be used in this manner?

We are looking to deploy sensors in remote locations, but some locations will have cell service available. The serial LTE modem project seems promising. Is there a sample project which does something similar? I opened the serial lte modem project in the segger ide but there is no code to look at. It's just a collection of libraries. Can it be customized?

Regards,

fe-hadella

[Håkon Alseth]

Hi,

 

The nRF9160 supports (D)TLS.

Are you going to download larger files? Note that NB1 and Cat M1 isn't "high throughput" transport layers, so I would strongly recommend that you test and see if the download speed is per your requirements.

 

The serial lte modem works as an extension to at_client, as described in the documentation here:

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.3.1/nrf/applications/serial_lte_modem/README.html#

If you want to run TLS, you have to set this up on a socket level, similar to what is done here:

https://github.com/nrfconnect/sdk-nrf/blob/master/samples/nrf9160/https_client/src/main.c#L192

This specific function issues the CA certification using this function:

https://github.com/nrfconnect/sdk-nrf/blob/master/samples/nrf9160/https_client/src/main.c#L64

 

However, you can do this by calling the AT command directly:

https://infocenter.nordicsemi.com/topic/ref_at_commands/REF/at_commands/mob_termination_ctrl_status/cmng_set.html?cp=2_1_4_28_0

 

The "sec_tag" you store your certificates to is the one you should use when creating the socket:

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.3.1/nrf/applications/serial_lte_modem/README.html#bsd-socket-at-commands 

 

You can also use the LTE Link monitor to issue certificates: https://infocenter.nordicsemi.com/topic/ug_link_monitor/UG/link_monitor/lm_certificate_manager.html?cp=9_3_2_5

  

Kind regards,

Håkon