Nrf9160 - modem shell with ppp

[RobertLukan]

I am trying to connect RPI(and/or Nvidia Jetson) with nrf9160 custom board(Icarusv2). I am using this custom board for other purposes and it works fine. For now I found only one possible option to connect 9160 with RPI(Nvidia Jetson) over UART connection with PPP. I have been trying to use Modem Shell example and it is working fine without PPP enabled. Once I enable PPP the connection to NRFCloud goes down and I cannot understand why. 

I have also tried SLM(Serial LTE modem) application, but I could not even establish LTE connection with that example when I added PPP options. I gave up on this example as it has less features comparing with Modem Shell. 

I have been using example from 2.6.0 and 2.6.1.

So I would be interested why MoSh example stops providing LTE connectivity once PPP is being established. Also some more general idea how to connect RPI(or Nvidia Jetson Dev kits) with NRF9160. 

[JONATHAN LL]

Update:

It is not working with current implementation of mosh ppp. mosh ppp sample uses modem raw sckts on a default PDN context for ip over ppp traffic. Raw sckts have a limitation in modem side so that other traffic for normal socket are not working at a same time. 

https://docs.nordicsemi.com/bundle/ncs-latest/page/nrfxlib/nrf_modem/doc/sockets/raw_sockets.html

Currently, "ppp down" need to be done and then do the other traffic on default pdn context, and then "ppp up" when ppp is needed again. Alternatively (not supported now in mosh) run ppp over another separate PDN context. Or alternatively create another context for that other traffic.

[RobertLukan]

Ok, understood. I guess the same limitation applies for SLM ? 

[JONATHAN LL]

Looking in to this and will update