Issue with Establishing Internet Connection on Linux Machine with nrf9160 DK SLM Application

[Amol_Chor]

Hi there,

I'm encountering an issue while attempting to establish an Internet connection on my Linux machine using the nrf9160 DK SLM (2.6.1) application. I've flashed the application using the overlay-ppp-without-cmux.overlay and overlay-ppp.conf files, and successfully established PPP communication between the Linux host machine and the nrf9160 DK.

However, despite following the steps outlined in the "Testing on Linux" guide, I'm unable to connect to the Internet from the Linux machine.

I've also attempted to use PPP support from the Modem shell application, but encountered the same issue.

To provide further clarity and assistance, I've attached screenshots from the Linux machine showing the SLM application PPP setup.

   

I am using NB-IoT network SIM in NRF9160 DK.

Any guidance or troubleshooting steps you can offer would be greatly appreciated. Thank you in advance for your help!

[dejans]

Hi,

Which Linux machine do you use?

Can you provide more information on what is shown in each of your screenshots?

Best regards,
Dejan

[Amol_Chor]

Thanks for quick reply !!

dejans said:

Which Linux machine do you use?

Ubuntu 20.04.6 LTS

dejans said:

Can you provide more information on what is shown in each of your screenshots?

above snippet shows the modem is up and PPP is started. In linux system which act as a host pppd is started using the command provided in Testing on Linux step number 3.

above snippet shows the pppd process is completed successfully in linux machine and IP is up.

above snippet shows the linux machine got the interface in ifconfig command i.e. ppp0.

above snippet is showing that ping command is used over the interface ppp0 to pinging the address 8.8.8.8

but there is no result after ping command.

[Amol_Chor]

dejans said:

AT%XSYSTEMMODE=0,1,0,0

In my case the system mode is set to :

> AT%XSYSTEMMODE?
[00:00:19.262,084] <dbg> slm_at_host: cmd_send: RX
                                      41 54 25 58 53 59 53 54  45 4d 4d 4f 44 45 3f    |AT%XSYST EMMODE? 

%XSYSTEMMODE: 0,1,0,2

OK
[00:00:19.284,057] <dbg> slm_at_host: slm_at_send_indicate: TX
                                      0d 0a 25 58 53 59 53 54  45 4d 4d 4f 44 45 3a 20 |..%XSYST EMMODE: 
                                      30 2c 31 2c 30 2c 32 0d  0a 0d 0a 4f 4b 0d 0a    |0,1,0,2. ...OK..

dejans said:

2. Drop the speed in overlay-ppp-without-cmux.overlay file to 115200

yes, It is set to 115200 only

here is overlay file which I am using :

2260.overlay-ppp-without-cmux.overlay

Still, I am not able to access the internet from the Linux machine.

[dejans]

Hi,

We will look further into this issue internally. I will get back to you during next week.

Best regards,
Dejan

[dejans]

Hi,

Could you try testing SLM sample using LTE-M instead of NB-IoT? What is result of the testing?

Best regards,
Dejan

[Amol_Chor]

Hi dejans 

In India there is only NB-IoT network supported.

that's why we are using NB-IoT network for testing !

thanks and regards,

Amol Chor.

[dejans]

Hi Amol,

Thanks for additional information.

You could try to enable following 2 Kconfigs

CONFIG_NET_L2_PPP_LOG_LEVEL_DBG
CONFIG_MODEM_MODULES_LOG_LEVEL_DBG

and provide full application log.

In addition, please provide modem trace. Documentation provides information about nrf91 modem traces using snippets and capturing modem trace.

Best regards,
Dejan