nRF9160-DK , Modem_shell demo , ppp unable to access the Internet

[JackyChen]

Hello,guys

I build nrf9160-dk modem_shell demo as cmd '$ west build -b nrf9160dk_nrf9160ns ' and then '$ west flash ', after the system running up, I try to ping baidu website，it works as follow picture.

And then I rebuild the Modem_shell demo with cmd ' $ west build -p -b nrf9160dk_nrf9160_ns -d build -- -DOVERLAY_CONFIG=overlay-ppp.conf' for supporting ppp function. After the system running up, I try to ping baidu website again，it works as follow picture and it work failed.

I can capture any data from another serial, I guess VCOM0 serial is shell and VCOM2 serial is ppp channel.

To test my guess，I plugged nrf9160-DK board into my Ubuntu virtual machine and disable Ubuntu network. Use minicom tool to connect VCOM0 and open nrf9160-DK shell in A terminal, set the custom configuration for PPP uart with cmd 'ppp uartconf -b 115200' . New B terminal for ppp connection , type cmd ' $sudo pppd -detach /dev/ttyACM2 115200 DK-ip:Ubuntu-ip noauth nocrtscts local ' , then A terminal return "Dial up connection up" . New C terminal and type cmd ' ifconfig ' , I can see ppp0 and it's ip ,I try to ping baidu website,it work as follow picture.

it can't access the Internet ? why ? Did I operate wrong? Please point out my mistakes.

The version of modem_fw I use is 1.3.0 , ncs version is 1.7.0.

[Håkon Alseth]

Hi,

 

You are unfortunately running into a known issue with NCS v1.7.0:

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/known_issues.html?v=v1-7-0#other-issues

 

Issue is described here:

https://github.com/zephyrproject-rtos/zephyr/issues/38516

 

While a fixed is posted in this PR:

https://github.com/zephyrproject-rtos/zephyr/pull/38517

 

Could you try applying the above PR and see if it works better on your end?

 

Kind regards,

Håkon

[JackyChen]

Hello Håkon, thanks for your technical support.

yep, I merge this commit

https://github.com/zephyrproject-rtos/zephyr/pull/38517/commits/4ecaebf2b04fd48a1def8f8adf7bd3cc1528c482

and do the experiment again. Unfortunately, my VM-Ubuntu unable to access the network, it still doesn't work.

Best wish.

Jackychen

[Håkon Alseth]

Hi,

 

The DNS and ping seems to work fine, but the PPP connection seems to be not functional.

Can you try to let it assign IP automatically, ie. do not specify it directly? It seems that you've tried several of these settings before, but I'm unsure which you've connected to when trying to ping.

sudo pppd -detach /dev/ttyACM0 115200 noauth nocrtscts local

 

Kind regards,

Håkon

[JackyChen]

emmm...  I have tried to type cmd "sudo pppd -detach /dev/ttyACM0 115200 noauth nocrtscts local" ,  but it unable to connect DK-board by ppp, it show 

，

and the DK-board didn't react at all.

Thanks~

JackyChen

[Håkon Alseth]

Did you issue "ppp up" in the terminal before attaching with "pppd ..." on the PC side?

 

Kind regards,

Håkon

[JackyChen]

No... because I change the computer to try, but I get the same result...

[Håkon Alseth]

Hi,

 

Could you try issuing "ppp up" before attaching via pppd?

It should print the following afterwards in the uart terminal:

mosh:~$ ppp up
modem data socket 4 created for modem data
PPP data socket 5 created
PPP net if up.

 

Kind regards,

Håkon

[JackyChen]

Oh, I forget "ppp up"...

Now I enter “ppp up” and then "pppd ..." ,  ppp0 still no working in the PC...

I

[Håkon Alseth]

Hi,

 

Are you still able to ping locally in the modem_shell application?

 

What I see is that your application does not populate the MTU size, while mine does:

*** Booting Zephyr OS build v2.6.99-ncs1-13-g20ac60fb9670  ***

MOSH version:       v1.7.0-325-gea83b7edbce1
MOSH build id:      custom
MOSH build variant: dev

Initializing modemlib...


mosh:~$ Initialized modemlib


Network registration status: searching
LTE cell changed: Cell ID: 21679616, Tracking area: 30401
Currently active system mode: LTE-M
RRC mode: Connected
Network registration status: Connected - home network
PSM parameter update: TAU: 3600, Active time: 0 seconds
mosh:~$ ppp up
modem data socket 4 created for modem data
PPP data socket 5 created
PPP net if up.

Modem config for system mode: LTE-M
Modem config for LTE preference: No preference, automatically selected by the modem
Currently active system mode: LTE-M
Modem FW version:      mfw_nrf9160_1.3.1
Operator PLMN:        "24201"
Current cell id:       21679616 (0x014ACE00)
Current band:          20
Current rsrp:          37: -104dBm
Current snr:           20: -5dB
Mobile network time and date: 21/11/05,14:24:47+04
PDP context info 1:
  CID:                0
  PDN ID:             0
  PDP context active: yes
  PDP type:           IPV4V6
  APN:                telenor.smart
  IPv4 MTU:           1500
  IPv4 address:       10.48.219.218
  IPv6 address:       2a02:2121:6b5:afad::ace:7717
  IPv4 DNS address:   193.213.112.4, 130.67.15.198
  IPv6 DNS address:   2001:4600:4:fff::52, 2001:4600:4:1fff::52
System time updated from cellular network

Here's the ping time to baidu.com via interface ppp0:

ping -I ppp0 baidu.com
PING baidu.com (220.181.38.251) from 10.48.219.218 ppp0: 56(84) bytes of data.
64 bytes from 220.181.38.251 (220.181.38.251): icmp_seq=1 ttl=44 time=357 ms
64 bytes from 220.181.38.251 (220.181.38.251): icmp_seq=2 ttl=44 time=396 ms
64 bytes from 220.181.38.251 (220.181.38.251): icmp_seq=3 ttl=44 time=368 ms
64 bytes from 220.181.38.251 (220.181.38.251): icmp_seq=4 ttl=44 time=406 ms

 

Kind regards,

Håkon