NRF9160 reboots when ppp started ( SLM in 2.6.0 )

[Amol_Chor]

Hi 

We are using STM32 board as a HOST controller and NRF9160 as cellular modem. On the STM32 board PPP client is running over serial interface.

We need PPP server support in NRF9160 so that STM32 board will communicate with AZURE cloud.

I have compiled SLM (serial LTE modem) application using overlay-ppp.conf and overlay-ppp-without-cmux.overlay.

The AT commands sent from external MCU STM32 board and we are using UART2 on SLM side for AT transaction.

we are facing nrf9160 reboot issue when PPP starts.

I have attached NRF9160_reboot.txt 

[00:00:10.995,178] <dbg> slm_at_host: cmd_send: RX
                                      41 54 2b 43 45 52 45 47  3f                      |AT+CEREG ?
[00:00:11.010,589] <dbg> slm_at_host: slm_at_send_indicate: TX
                                      0d 0a 2b 43 45 52 45 47  3a 20 32 2c 32 2c 22 32 |..+CEREG : 2,2,"2
                                      33 41 33 22 2c 22 30 45  31 35 45 39 35 31 22 2c |3A3","0E 15E951",
                                      39 0d 0a 0d 0a 4f 4b 0d  0a                      |9....OK. .
[00:00:11.045,623] <dbg> slm_at_host: cmd_send: RX
                                      41 54 2b 43 4f 50 53 3f                          |AT+COPS?
[00:00:11.060,852] <dbg> slm_at_host: slm_at_send_indicate: TX
                                      0d 0a 2b 43 4f 50 53 3a  20 30 0d 0a 0d 0a 4f 4b |..+COPS:  0....OK
                                      0d 0a                                            |..
[00:00:11.086,242] <dbg> slm_at_host: cmd_send: RX
                                      41 54 2b 43 53 51                                |AT+CSQ
[00:00:11.101,715] <dbg> slm_at_host: slm_at_send_indicate: TX
                                      0d 0a 2b 43 53 51 3a 20  39 39 2c 39 39 0d 0a 0d |..+CSQ:  99,99...
                                      0a 4f 4b 0d 0a                                   |.OK..
[00:00:15.548,492] <inf> slm_ppp: Connection up. Starting PPP.
[00:00:15.555,297] <dbg> slm_at_host: slm_at_send_indicate: TX
                                      0d 0a                                            |..
[00:00:15.571,166] <dbg> slm_at_host: slm_at_send_indicate: TX
                                      2b 43 4e 45 43 5f 45 53  4d 3a 20 35 30 2c 30 0d |+CNEC_ES M: 50,0.
                                      0a                                               |.
[00:00:15.596,527] <dbg> slm_ppp: pdp_ctx_event_handler: Default PDN connection event 0 received.
[00:00:15.606,079] <dbg> slm_at_host: slm_at_send_indicate: TX
                                      0d 0a                                            |..
[00:00:15.621,856] <dbg> slm_at_host: slm_at_send_indicate: TX
                                      2b 43 45 52 45 47 3a 20  35 2c 22 32 33 41 33 22 |+CEREG:  5,"23A3"
                                      2c 22 30 45 31 35 45 39  35 31 22 2c 39 0d 0a    |,"0E15E9 51",9..
[00:00:15.647,277] <dbg> slm_at_host: cmd_send: RX
                                      41 54 2b 43 45 52 45 47  3f                      |AT+CEREG ?
[00:00:15.662,658] <dbg> slm_at_host: slm_at_send_indicate: TX
                                      0d 0a 2b 43 45 52 45 47  3a 20 32 2c 35 2c 22 32 |..+CEREG : 2,5,"2
                                      33 41 33 22 2c 22 30 45  31 35 45 39 35 31 22 2c |3A3","0E 15E951",
                                      39 0d 0a 0d 0a 4f 4b 0d  0a                      |9....OK. .
[00:00:15.697,509] <dbg> slm_at_host: cmd_send: RX
                                      41 54 2b 43 4f 50 53 3f                          |AT+COPS?
[00:00:15.712,860] <dbg> slm_at_host: slm_at_send_indicate: TX
                                      0d 0a 2b 43 4f 50 53 3a  20 30 2c 32 2c 22 34 30 |..+COPS:  0,2,"40
                                      34 39 30 22 2c 39 0d 0a  0d 0a 4f 4b 0d 0a       |490",9.. ..OK..
[00:00:15.738,189] <dbg> slm_at_host: cmd_send: RX
                                      41 54 2b 43 45 52 45 47  3f                      |AT+CEREG ?
[00:00:15.753,509] <dbg> slm_at_host: slm_at_send_indicate: TX
                                      0d 0a 2b 43 45 52 45 47  3a 20 32 2c 35 2c 22 32 |..+CEREG : 2,5,"2
                                      33 41 33 22 2c 22 30 45  31 35 45 39 35 31 22 2c |3A3","0E 15E951",
                                      39 0d 0a 0d 0a 4f 4b 0d  0a                      |9....OK. .
[00:00:15.788,269] <dbg> slm_at_host: cmd_send: RX
                                      41 54 2b 43 4f 50 53 3f                          |AT+COPS?
[00:00:15.803,497] <dbg> slm_at_host: slm_at_send_indicate: TX
                                      0d 0a 2b 43 4f 50 53 3a  20 30 2c 32 2c 22 34 30 |..+COPS:  0,2,"40
                                      34 39 30 22 2c 39 0d 0a  0d 0a 4f 4b 0d 0a       |490",9.. ..OK..
[00:00:15.828,765] <dbg> slm_at_host: cmd_send: RX
                                      41 54 2b 43 47 41 54 54  3f                      |AT+CGATT ?
[00:00:15.844,085] <dbg> slm_at_host: slm_at_send_indicate: TX
                                      0d 0a 2b 43 47 41 54 54  3a 20 31 0d 0a 0d 0a 4f |..+CGATT : 1....O
                                      4b 0d 0a                                         |K..
[00:00:15.869,323] <dbg> slm_at_host: cmd_send: RX
                                      41 54 2b 43 47 45 52 45  50 3d 31 2c 30          |AT+CGERE P=1,0
[00:00:15.884,368] <dbg> slm_util: slm_util_at_cmd_no_intercept: Forwarding "AT+CGEREP=1,0" to the modem.
[00:00:15.895,111] <dbg> slm_at_host: slm_at_send_indicate: TX
                                      0d 0a 4f 4b 0d 0a                                |..OK..
[00:00:15.910,827] <dbg> slm_at_host: cmd_send: RX
                                      41 54 2b 43 47 50 41 44  44 52 3d 31             |AT+CGPAD DR=1
[00[00:00:15.927,062] <dbg> slm_at_host: slm_at_send_indicate: TX
                                      0d 0a 4f 4b 0d 0a                                |..OK..
:00:15.926,696] <dbg> slm_ppp: ppp_start: MTU set to 1500.
[00:00:15.948,944] <dbg> net_mgmt: net_mgmt_event_notify_with_info: (0x20010f80): Notifying Event layer 1 code 1 type 4
[00:00:15.960,327] <dbg> net_mgmt: mgmt_thread: (0x20016d60): Handling events, forwarding it relevantly
[00:00:15.970,306] <dbg> net_mgmt: mgmt_run_callbacks: (0x20016d60): Event layer 1 code 1 cmd 4
[00:00:15.980,041] <dbg> net_mgmt: net_mgmt_event_notify_with_info: (0x20010f80): Notifying Event layer 1 code 1 type 2
[00:00:15.991,455] <dbg> net_mgmt: mgmt_thread: (0x20016d60): Handling events, forwarding it relevantly
[00:00:16.001,403] <dbg> net_mgmt: mgmt_run_callbacks: (0x20016d60): Event layer 1 code 1 cmd 2
[00:00:16.010,711] <dbg> net_mgmt: mgmt_run_callbacks: (0x20016d60): Running callback 0x200115a4 : 0x29b1d
[00:00:16.021,026] <dbg> net_mgmt: net_mgmt_event_notify_with_info: (0x20016d60): Notifying Event layer 1 code 521 type 1
[00:00:00.251,007] <err> spi_nor: Device id 00 00 00 does not match config c2 28 17
[00:00:00.259,338] <dbg> net_pkt: net_pkt_init: (0x200195b0): Allocating 44 RX (2816 bytes), 44 TX (2816 bytes), 88 RX data (0 bytes) and 88 TX data (0 bytes) buffers
[00:00:00.274,658] <dbg> net_mgmt: net_mgmt_event_init: (0x200195b0): Net MGMT initialized: queue of 5 entries, stack size of 800
[00:00:00.286,743] <dbg> net_l2_ppp: net_ppp_init: (0x200195b0): Initializing PPP L2 0x200112f8 for iface 0x20010ed4
[00:00:00.297,729] <dbg> net_mgmt: net_mgmt_add_event_callback: (0x200195b0): Adding event callback 0x200115a4
[00:00:00.308,166] <dbg> net_l2_ppp: ipcp_init: (0x200195b0): proto IPCP (0x8021) fsm 0x20011400
[00:00:00.317,413] <dbg> net_l2_ppp: ipv6cp_init: (0x200195b0): proto IPV6CP (0x8057) fsm 0x200114d8
[00:00:00.326,995] <dbg> net_l2_ppp: lcp_init: (0x200195b0): proto LCP (0xc021) fsm 0x20011330
[00:00:00.336,090] <wrn> net_if: You have 1 IPv6 net_if addresses but 2 network interfaces
[00:00:00.344,970] <wrn> net_if: Consider increasing CONFIG_NET_IF_MAX_IPV6_COUNT value.
[00:00:00.354,217] <wrn> net_if: You have 1 IPv4 net_if addresses but 2 network interfaces
[00:00:00.363,098] <wrn> net_if: Consider increasing CONFIG_NET_IF_MAX_IPV4_COUNT value.
*** Booting nRF Connect SDK v3.5.99-ncs1 ***
[00:00:00.375,823] <inf> at_cmd_custom: Custom AT commands enabled with 2 entries.
[00:00:00.383,850] <dbg> net_l2_ppp: tx_handler: (0x20016b98): PPP TX started
[00:00:00.391,387] <dbg> slm: main: RR: 0x00010000
[00:00:00.403,045] <inf> fs_nvs: 2 Sectors of 4096 bytes
[00:00:00.408,752] <inf> fs_nvs: alloc wra: 0, fe8
[00:00:00.413,970] <inf> fs_nvs: data wra: 0, 0
[00:00:00.656,097] <inf> slm: lib_modem init: 0
[00:00:00.667,633] <inf> mcuboot_util: Image index: 0, Swap type: none
[00:00:00.674,530] <inf> slm: Serial LTE Modem
[00:00:00.772,796] <dbg> net_mgmt: net_mgmt_add_event_callback: (0x200195b0): Adding event callback 0x200199b4
[00:00:00.783,233] <dbg> slm_ppp: slm_ppp_init: PPP initialized.
[00:00:00.789,672] <inf> slm_uart_handler: UART baud: 115200 d/p/s-bits: 3/0/1 HWFC: 1
[00:00:00.798,095] <dbg> slm_at_host: slm_at_send_indicate: TX
                                      52 65 61 64 79 0d 0a                             |Ready..
[00:00:00.813,903] <inf> slm_at_host: at_host init done
[00:00:00.819,732] <dbg> slm: configure_power_pin_interrupt: Configured interrupt (0x3400000) on power pin (31).

NRF9160_reboot.txt

here I am attaching my conf files and overlay files which is used for building the SLM app

overlay-ppp.confoverlay-ppp-without-cmux.overlay

75343.nrf9160dk_nrf9160_ns.overlay2211.nrf9160dk_nrf9160_ns.conf

[dejans]

Hi,

Do you use NCS v2.6.0?

Your log shows "You have 1 IPv4 net_if addresses but 2 network interfaces" and "Consider increasing CONFIG_NET_IF_MAX_IPV4_COUNT value." Can you try to increase CONFIG_NET_IF_MAX_IPV4_COUNT to 2? 

Best regards,
Dejan

[Amol_Chor]

Do you use NCS v2.6.0?

                     yes and also checked on v2.6.1

Thanks for the reply!

Although increasing the CONFIG_NET_IF_MAX_IPV4_COUNT value has successfully removed the warning, the reboot issue still persists.

I have already enabled the debug logs option for PPP in the configuration file, which can be found in the overlay-ppp.conf file.

However, disabling the debug logs option in the PPP configuration file prevents the reboot issue from occurring.

[dejans]

Hi,

Robert Colvin said:

can you please confirm if nRF9160 using SLM to implement PPP is possible with registered with NB-IoT, or is it only available for LTE-M?

nRF9160 is multimode LTE-M/NB-IoT modem and SLM supports both LTE-M and NB-IoT.

Amol_Chor  Is your issue resolved by disabling debug log options in the PPP configuration?

Best regards,
Dejan

[Amol_Chor]

dejans said:

Is your issue resolved by disabling debug log options in the PPP c

Yes !!
but i want to enable those logs for debugging purpose.

[Amol_Chor]

dejans said:

nRF9160 is multimode LTE-M/NB-IoT modem and SLM supports both LTE-M and

yes, you are right nrf9160 is multimode.

But we want to know whether SLM can specifically be used for implementing PPP when the nRF9160 is registered with NB-IoT?

[dejans]

Hi,

It should be possible to use nrf9160 registered to NB-IoT with the following modifications to testing on Linux:
- Set AT%XSYSTEMMODE=0,1,0,0, before the first AT+CFUN=1
- Drop the speed in overlay-ppp-without-cmux.overlay file to 115200

Best regards,
Dejan