not able to get IP address using NB-IoT network using PPP.

[Amol_Chor]

Hi,

I am working on custom board which has nrf9160 as modem and stm32 as host controller.

here I am used lwip stack on stm32 controller to get the IP address.

I have NB-IoT SIM card on nrf9160 and I am trying to get IP address from it.

Now the issue is while using LWIP stack I am not the IP address.

Here I am attach the logs form LTE network which get the IP address from LWIP stack using PPP on Quectel Modem.

<INF>    17763 [CellularSe] client ppp_notify_phase_cb: PPP_PHASE_DEAD
>
<INF>    17763 [CellularSe] ppposif_client_dead
>
<L  >    17763 [CellularSe] ppp_connect[0]: holdoff=0
>
<L  >    17763 [CellularSe] ppp phase changed[0]: phase=3
>
<L  >    18003 [TCP/IP    ] sct calling h=dns_tmr t=0 arg=0x80ddf44
>
<L  >    18003 [TCP/IP    ] tcpip: dns_tmr()
>
<L  >    18003 [TCP/IP    ] dns_tmr: dns_check_entries
>
<L  >    18003 [TCP/IP    ] sys_timeout: 0x2007dde4 abs_time=19003 handler=dns_tmr arg=0x80ddf44
>
<INF>    18263 [CellularSe] client ppp_notify_phase_cb: PPP_PHASE_INITIALIZE
>
<L  >    18263 [CellularSe] pppos_connect: unit 0: connecting
>
<L  >    18263 [CellularSe] ppp_start[0]
>
<L  >    18263 [CellularSe] ppp phase changed[0]: phase=6
>
<INF>    18763 [CellularSe] client ppp_notify_phase_cb: 6
>
<L  >    18763 [CellularSe] pppos_send_config[0]: out_accm=FF FF FF FF
>
<L  >    18763 [CellularSe] ppp_send_config[0]
>
<L  >    18763 [CellularSe] pppos_recv_config[0]: in_accm=FF FF FF FF
>
<L  >    18763 [CellularSe] ppp_recv_config[0]
>
<L  >    18763 [CellularSe] ppp: auth protocols:
>
<L  >    18763 [CellularSe]  PAP=0
>
<L  >    18763 [CellularSe]
>
<L  >    18763 [CellularSe] pbuf_alloc(length=24)
>
<L  >    18763 [CellularSe] pbuf_alloc(length=24) == 0x2007da3c
>
<L  >    18763 [CellularSe] pbuf_alloc(length=0)
>
<L  >    18763 [CellularSe] pbuf_alloc(length=0) == 0x2007d82c
>
<L  >    18767 [CellularSe] pbuf_free(0x2007d82c)
>
<L  >    18767 [CellularSe] pbuf_free: deallocating 0x2007d82c
>
<L  >    18767 [CellularSe] pppos_write[0]: len=24
>
<L  >    18767 [CellularSe] pbuf_free(0x2007da3c)
>
<L  >    18767 [CellularSe] pbuf_free: deallocating 0x2007da3c
>
<L  >    18767 [CellularSe] sys_timeout: 0x2007ddd0 abs_time=24767 handler=(fsm_timeout) arg=0x2007f47c
>
<L  >    18767 [CellularSe] ppp_start[0]: finished
>
<L  >    18769 [PPPosifClt] pbuf_alloc(length=1)
>
<L  >    18769 [PPPosifClt] pbuf_alloc(length=1) == 0x2007da3c
>
<L  >    18769 [PPPosifClt] tcpip_inpkt: PACKET 0x2007da3c/0x2004475c
>
<L  >    18769 [PPPosifClt] pppos_input[0]: got 1 bytes
>
<L  >    18769 [PPPosifClt] pbuf_free(0x2007da3c)
>
<L  >    18769 [PPPosifClt] pbuf_free: deallocating 0x2007da3c
>
<L  >    18769 [PPPosifClt] pbuf_alloc(length=2)
>
<L  >    18769 [PPPosifClt] pbuf_alloc(length=2) == 0x2007da3c
>
<L  >    18769 [PPPosifClt] tcpip_inpkt: PACKET 0x2007da3c/0x2004475c
>
<L  >    18769 [PPPosifClt] pppos_input[0]: got 2 bytes
>
<L  >    18770 [PPPosifClt] pbuf_free(0x2007da3c)
>
<L  >    18770 [PPPosifClt] pbuf_free: deallocating 0x2007da3c
>
<L  >    18770 [PPPosifClt] pbuf_alloc(length=3)
>
<L  >    18770 [PPPosifClt] pbuf_alloc(length=3) == 0x2007da3c
>
<L  >    18770 [PPPosifClt] tcpip_inpkt: PACKET 0x2007da3c/0x2004475c
>
<L  >    18770 [PPPosifClt] pppos_input[0]: got 3 bytes
>
<L  >    18770 [PPPosifClt] pbuf_free(0x2007da3c)
>
<L  >    18770 [PPPosifClt] pbuf_free: deallocating 0x2007da3c
>
<L  >    18770 [PPPosifClt] pbuf_alloc(length=3)
>
<L  >    18770 [PPPosifClt] pbuf_alloc(length=3) == 0x2007da3c
>
<L  >    18770 [PPPosifClt] tcpip_inpkt: PACKET 0x2007da3c/0x2004475c
>
<L  >    18770 [PPPosifClt] pppos_input[0]: got 3 bytes
>
<L  >    18770 [PPPosifClt] pbuf_alloc(length=0)
>
<L  >    18770 [PPPosifClt] pbuf_alloc(length=0) == 0x2007d82c
>
<L  >    18770 [PPPosifClt] pbuf_free(0x2007da3c)
>
<L  >    18770 [PPPosifClt] pbuf_free: deallocating 0x2007da3c
>
<L  >    18770 [PPPosifClt] pbuf_alloc(length=3)
>
<L  >    18770 [PPPosifClt] pbuf_alloc(length=3) == 0x2007da3c
>
<L  >    18770 [PPPosifClt] tcpip_inpkt: PACKET 0x2007da3c/0x2004475c
>
<L  >    18770 [PPPosifClt] pppos_input[0]: got 3 bytes
>
<L  >    18770 [PPPosifClt] pbuf_free(0x2007da3c)
>
<L  >    18770 [PPPosifClt] pbuf_free: deallocating 0x2007da3c
>
<L  >    18770 [PPPosifClt] pbuf_alloc(length=3)
>
<L  >    18770 [PPPosifClt] pbuf_alloc(length=3) == 0x2007da3c
>
<L  >    18770 [PPPosifClt] tcpip_inpkt: PACKET 0x2007da3c/0x2004475c
>
<L  >    18771 [PPPosifClt] pppos_input[0]: got 3 bytes
>
<L  >    18771 [PPPosifClt] pbuf_free(0x2007da3c)
>
<L  >    18771 [PPPosifClt] pbuf_free: deallocating 0x2007da3c
>
<L  >    18771 [PPPosifClt] pbuf_alloc(length=3)
>
<L  >    18771 [PPPosifClt] pbuf_alloc(length=3) == 0x2007da3c
>
<L  >    18771 [PPPosifClt] tcpip_inpkt: PACKET 0x2007da3c/0x2004475c
>
<L  >    18771 [PPPosifClt] pppos_input[0]: got 3 bytes
>
<L  >    18771 [PPPosifClt] pbuf_free(0x2007da3c)
>
<L  >    18771 [PPPosifClt] pbuf_free: deallocating 0x2007da3c
>
<L  >    18771 [PPPosifClt] pbuf_alloc(length=3)
>
<L  >    18771 [PPPosifClt] pbuf_alloc(length=3) == 0x2007da3c
>
<L  >    18771 [PPPosifClt] tcpip_inpkt: PACKET 0x2007da3c/0x2004475c
>
<L  >    18771 [PPPosifClt] pppos_input[0]: got 3 bytes
>
<L  >    18771 [PPPosifClt] pbuf_free(0x2007da3c)
>
<L  >    18771 [PPPosifClt]
>
<L  >    18786 [PPPosifClt] pbuf_free(0x2007d40c)
>
<L  >    18787 [P
>
<INF>    19287 [PPPosifClt] client ppp_notify_phase_cb: 7
>
<L  >    19287 [PPPosifClt] ppp phase changed[0]: phase=9
>
<INF>    19787 [PPPosifClt] client ppp_notify_phase_cb: PPP_PHASE_NETWORK
>
<INF>    19787 [PPPosifClt] ppposif_client_network
>
<L  >    19787 [PPPosifClt] pbuf_alloc(length=32)
>
<L  >    19787 [PPPosifClt] pbuf_alloc(length=32) == 0x2007d61c
>
<L  >    19787 [PPPosifClt] pbuf_alloc(length=0)
>
<L  >    19787 [PPPosifClt] pbuf_alloc(length=0) == 0x2007d40c
>
<L  >    19790 [PPPosifClt] pbuf_free(0x2007d40c)
>
<L  >    19790 [PPPosifClt] pbuf_free: deallocating 0x2007d40c
>
<L  >    19790 [PPPosifClt] pppos_write[0]: len=32
>
<L  >    19790 [PPPosifClt] pbuf_free(0x2007d61c)
>
<L  >    19790 [PPPosifClt] pbuf_free: deallocating 0x2007d61c
>
<L  >    19790 [PPPosifClt] sys_timeout: 0x2007ddd0 abs_time=25790 handler=(fsm_timeout) arg=0x2008063c
>
<L  >    19790 [PPPosifClt] pbuf_free(0x2007d82c)
>
<L  >    19790 [PPPosifClt] pbuf_free: deallocating 0x2007d82c
>
<L  >    19790 [PPPosifClt] pbuf_free(0x2007da3c)
>
<L  >    19790 [PPPosifClt] pbuf_free: deallocating 0x2007da3c
>
<L  >    19790 [PPPosifClt] pbuf_alloc(length=22)
>
<L  >    19790 [PPPosifClt] pbuf_alloc(length=22) == 0x2007da3c
>
<L  >    19790 [PPPosifClt] tcpip_inpkt: PACKET 0x2007da3c/0x2004475c
>
<L  >    19790 [PPPosifClt] pppos_input[0]: got 22 bytes
>
<L  >    19790 [PPPosifClt] pbuf_alloc(length=0)
>
<L  >    19790 [PPPosifClt] pbuf_alloc(length=0) == 0x2007d82c
>
<L  >    19791 [PPPosifClt] pbuf_remove_header: old 0x2007d83c new 0x2007d83e (2)
>
<L  >    19791 [PPPosifClt] pbuf_free(0x2007d82c)
>
<L  >    19791 [PPPosifClt] pbuf_free: deallocating 0x2007d82c
>
<L  >    19791 [PPPosifClt] pbuf_free(0x2007da3c)
>
<L  >    19791 [PPPosifClt] pbuf_free: deallocating 0x2007da3c
>
<L  >    19806 [TCP/IP    ] sct calling h=dns_tmr t=803 arg=0x80ddf44
>
<L  >    19806 [TCP/IP    ] tcpip: dns_tmr()
>
<L  >    19806 [TCP/IP    ] dns_tmr: dns_check_entries
>
<L  >    19806 [TCP/IP    ] sys_timeout: 0x2007dde4 abs_time=20003 handler=dns_tmr arg=0x80ddf44
>
<L  >    19807 [PPPosifClt] pbuf_alloc(length=1)
>
<L  >    19807 [PPPosifClt] pbuf_alloc(length=1) == 0x2007da3c
>
<L  >    19807 [PPPosifClt] tcpip_inpkt: PACKET 0x2007da3c/0x2004475c
>
<L  >    19807 [PPPosifClt] pppos_input[0]: got 1 bytes
>
<L  >    19807 [PPPosifClt] pbuf_free(0x2007da3c)
>
<L  >    19807 [PPPosifClt] pbuf_free: deallocating 0x2007da3c
>
<L  >    19807 [PPPosifClt] pbuf_alloc(length=2)
>
<L  >    19807 [PPPosifClt] pbuf_alloc(length=2) == 0x2007da3c
>
<L  >    19807 [PPPosifClt] tcpip_inpkt: PACKET 0x2007da3c/0x2004475c
>
<L  >    19807 [PPPosifClt] pppos_input[0]: got 2 bytes
>
<L  >    19807 [PPPosifClt] pbuf_free(0x2007da3c)
>
<L  >    19807 [PPPosifClt] pbuf_free: deallocating 0x2007da3c
>
<L  >    19807 [PPPosifClt] pbuf_alloc(length=3)
>
<L  >    19807 [PPPosifClt] pbuf_alloc(length=3) == 0x2007da3c
>
<L  >    19807 [PPPosifClt] tcpip_inpkt: PACKET 0x2007da3c/0x2004475c
>
<L  >    19807 [PPPosifClt] pppos_input[0]: got 3 bytes
>
<L  >    19807 [PPPosifClt] pbuf_alloc(length=0)
>
<L  >    19807 [PPPosifClt] pbuf_alloc(length=0) == 0x2007d82c
>
<L  >    19807 [PPPosifClt] pbuf_free(0x2007da3c)
>
<L  >    19808 [PPPosifClt] pbuf_free: deallocating 0x2007da3c
>
<L  >    19808 [PPPosifClt] pbuf_alloc(length=4)
>
<L  >    19808 [PPPosifClt] pbuf_alloc(length=4) == 0x2007da3c
>
<L  >    19808 [PPPosifClt] tcpip_inpkt: PACKET 0x2007da3c/0x2004475c
>
<L  >    19808 [PPPosifClt] pppos_input[0]: got 4 bytes
>
<L  >    19808 [PPPosifClt] pbuf_remove_header: old 0x2007d83c new 0x2007d83e (2)
>
<L  >    19808 [PPPosifClt] pbuf_alloc(length=14)
>
<L  >    19808 [PPPosifClt] pbuf_alloc(length=14) == 0x2007d61c
>
<L  >    19808 [PPPosifClt] pbuf_alloc(length=0)
>
<L  >    19808 [PPPosifClt] pbuf_alloc(length=0) == 0x2007d40c
>
<L  >    19809 [PPPosifClt] pbuf_free(0x2007d40c)
>
<L  >    19809 [PPPosifClt] pbuf_free: deallocating 0x2007d40c
>
<L  >    19809 [PPPosifClt] pppos_write[0]: len=14
>
<L  >    19810 [PPPosifClt] pbuf_free(0x2007d61c)
>
<L  >    19810 [PPPosifClt] pbuf_free: deallocating 0x2007d61c
>
<L  >    19810 [PPPosifClt] pbuf_free(0x2007d82c)
>
<L  >    19810 [PPPosifClt] pbuf_free: dealloc
>
<L  >    19813 [PPPosifClt] pbuf_free(0x2007d40c)
>
<INF>    20323 [PPPosifClt] client ppp_notify_phase_cb: PPP_PHASE_RUNNING
>
<INF>    20323 [PPPosifClt] CST: CST_notif_callback (Data Cache event=0)
>
<INF>    20323 [PPPosifClt] CST: CST_send_message: data cache 0
>
<L  >    20323 [PPPosifClt] pbuf_free(0x2007d82c)
>
<L  >    20323 [PPPosifClt] pbuf_free: deallocating 0x2007d82c
>
<L  >    20323 [PPPosifClt] pbuf_free(0x2007da3c)
>
<L  >    20323 [PPPosifClt] pbuf_free: deallocating 0x2007da3c
>
<L  >    20323 [TCP/IP    ] sct calling h=dns_tmr t=320 arg=0x80ddf44
>
<L  >    20323 [TCP/IP    ] tcpip: dns_tmr()
>
<L  >    20323 [TCP/IP    ] dns_tmr: dns_check_entries
>
<L  >    20323 [TCP/IP    ] sys_timeout: 0x2007dde4 abs_time=21003 handler=dns_tmr arg=0x80ddf44
>
<INF>    20323 [CellularSe] CST: CST_notif_callback (Data Cache event=0)
>
<INF>    20323 [CellularSe] CST: CST_send_message: data cache 0
>
<INF>    20323 [CellularSe] CST: AUTOM TASK: CST_PPP_CONFIG_ON_GOING_STATE - PPP_OPENED_EVENT
>
<INF>    20323 [CellularSe] CST: New State: MODEM_DATA_READY_STATE
>
<INF>    20323 [CellularSe] CST: modem state : CA_MODEM_STATE_DATAREADY
>
<INF>    20323 [CellularSe] CST: CST_notif_callback (Data Cache event=0)
>
<INF>    20323 [CellularSe] CST: CST_send_message: data cache 0
>
<INF>    20323 [CellularSe] CST: CST_send_message: NO_EVENT
>
<INF>    20323 [CellularSe] CST: CST_notif_callback (Data Cache event=2)
>
<INF>    20323 [CellularSe] CellularApp: Modem ready to transmit data
>
<L  >    20324 [CellularSe] sys_timeout: 0x2007ddd0 abs_time=24086 handler=sntp_request arg=0
>
<INF>    20324 [CellularSe] CST: CST_notif_callback (Data Cache event=0)
>
<INF>    20324 [CellularSe] CST: CST_send_message: data cache 0
>
<INF>    20324 [CellularSe] CST: CST_notif_callback (Data Cache event=1)
>
<INF>    20324 [CellularSe] CST: CST_send_message: data cache 1
>
<INF>    20324 [CellularSe] Network is up with IP 10.65.175.125
>
<INF>    20324 [CellularSe] CST: rt_state_ppp = DC_SERVICE_UNAVAIL. Nothing to do
>
<INF>    20324 [CellularSe] CST: autom_event = no event
>
<INF>    20324 [CellularSe] CST: rt_state_ppp = DC_SERVICE_UNAVAIL. Nothing to do
>
<INF>    20324 [CellularSe] CST: autom_event = no event
>
<INF>    20324 [CellularSe] CST: autom_event = no event
>
<INF>    20324 [CellularSe] CST: rt_state_ppp = DC_SERVICE_UNAVAIL. Nothing to do
>
<INF>    20324 [CellularSe] CST: autom_event = no event
>
<INF>    20324 [CellularSe] CST: autom_event = no event

when I used NRF9160 modem I am not able to IP address from same LWIP stack using PPP.
here is the logs when I used NRF9160 as  modem (application used in nrf9160 Serial LTE modem (2.5.0)).

<INF>    70841 [CellularSe] client ppp_notify_phase_cb: PPP_PHASE_DEAD
>
<INF>    70841 [CellularSe] ppposif_client_dead
>
<L  >    70841 [CellularSe] ppp_connect[0]: holdoff=0
>
<L  >    70841 [CellularSe] ppp phase changed[0]: phase=3
>
<L  >    71012 [TCP/IP    ] sct calling h=dns_tmr t=0 arg=0x80e5ebc
>
<L  >    71012 [TCP/IP    ] tcpip: dns_tmr()
>
<L  >    71012 [TCP/IP    ] dns_tmr: dns_check_entries
>
<L  >    71012 [TCP/IP    ] sys_timeout: 0x20083558 abs_time=72012 handler=dns_tmr arg=0x80e5ebc
>
<INF>    71341 [CellularSe] client ppp_notify_phase_cb: PPP_PHASE_INITIALIZE
>
<L  >    71341 [CellularSe] pppos_connect: unit 0: connecting
>
<L  >    71341 [CellularSe] ppp_start[0]
>
<L  >    71341 [CellularSe] ppp phase changed[0]: phase=6
>
<INF>    71841 [CellularSe] client ppp_notify_phase_cb: 6
>
<L  >    71841 [CellularSe] pppos_send_config[0]: out_accm=FF FF FF FF
>
<L  >    71841 [CellularSe] ppp_send_config[0]
>
<L  >    71841 [CellularSe] pppos_recv_config[0]: in_accm=FF FF FF FF
>
<L  >    71841 [CellularSe] ppp_recv_config[0]
>
<L  >    71841 [CellularSe] ppp: auth protocols:
>
<L  >    71841 [CellularSe]  PAP=0
>
<L  >    71841 [CellularSe]
>
<L  >    71841 [CellularSe] pbuf_alloc(length=24)
>
<L  >    71841 [CellularSe] pbuf_alloc(length=24) == 0x200831b0
>
<L  >    71841 [CellularSe] pbuf_alloc(length=0)
>
<L  >    71841 [CellularSe] pbuf_alloc(length=0) == 0x20082fa0
>
<L  >    71845 [CellularSe] pbuf_free(0x20082fa0)
>
<L  >    71845 [CellularSe] pbuf_free: deallocating 0x20082fa0
>
<L  >    71845 [CellularSe] pppos_write[0]: len=24
>
<L  >    71845 [CellularSe] pbuf_free(0x200831b0)
>
<L  >    71845 [CellularSe] pbuf_free: deallocating 0x200831b0
>
<L  >    71845 [CellularSe] sys_timeout: 0x20083544 abs_time=77845 handler=(fsm_timeout) arg=0x20084bf0
>
<L  >    71845 [CellularSe] ppp_start[0]: finished
>
<INF>    71862 [CellularSe] CST: CST_notif_callback (Data Cache event=2)
>
<INF>    71862 [CellularSe] CST: CST_notif_callback (Data Cache event=0)
>
<INF>    71863 [CellularSe] CST: CST_send_message: data cache 0
>
<INF>    71863 [CellularSe] CST: CST_notif_callback (Data Cache event=1)
>
<INF>    71863 [CellularSe] CST: CST_send_message: data cache 1
>
<INF>    71863 [CellularSe] CST: New State: CST_PPP_CONFIG_ON_GOING_STATE
>
<INF>    71863 [CellularSe] CST: rt_state_ppp = DC_SERVICE_UNAVAIL. Nothing to do
>
<INF>    71863 [CellularSe] CST: autom_event = no event
>
<INF>    71863 [CellularSe] CST: autom_event = no event
>
<L  >    72012 [TCP/IP    ] sct calling h=dns_tmr t=0 arg=0x80e5ebc
>
<L  >    72012 [TCP/IP    ] tcpip: dns_tmr()
>
<L  >    72012 [TCP/IP    ] dns_tmr: dns_check_entries
>
<L  >    72012 [TCP/IP    ] sys_timeout: 0x20083558 abs_time=73012 handler=dns_tmr arg=0x80e5ebc
>
<L  >    73012 [TCP/IP    ] sct calling h=dns_tmr t=0 arg=0x80e5ebc
>
<L  >    73012 [TCP/IP    ] tcpip: dns_tmr()
>
<L  >    73012 [TCP/IP    ] dns_tmr: dns_check_entries
>
<L  >    73012 [TCP/IP    ] sys_timeout: 0x20083558 abs_time=74012 handler=dns_tmr arg=0x80e5ebc
>
<L  >    74012 [TCP/IP    ] sct calling h=dns_tmr t=0 arg=0x80e5ebc
>
<L  >    74012 [TCP/IP    ] tcpip: dns_tmr()
>
<L  >    74012 [TCP/IP    ] dns_tmr: dns_check_entries
>
<L  >    74012 [TCP/IP    ] sys_timeout: 0x20083558 abs_time=75012 handler=dns_tmr arg=0x80e5ebc
>
<L  >    75012 [TCP/IP    ] sct calling h=dns_tmr t=0 arg=0x80e5ebc
>
<L  >    75012 [TCP/IP    ] tcpip: dns_tmr()
>
<L  >    75012 [TCP/IP    ] dns_tmr: dns_check_entries
>
<L  >    75012 [TCP/IP    ] sys_timeout: 0x20083558 abs_time=76012 handler=dns_tmr arg=0x80e5ebc
>
<L  >    76012 [TCP/IP    ] sct calling h=dns_tmr t=0 arg=0x80e5ebc
>
<L  >    76012 [TCP/IP    ] tcpip: dns_tmr()
>
<L  >    76012 [TCP/IP    ] dns_tmr: dns_check_entries
>
<L  >    76012 [TCP/IP    ] sys_timeout: 0x20083558 abs_time=77012 handler=dns_tmr arg=0x80e5ebc
>
<L  >    77012 [TCP/IP    ] sct calling h=dns_tmr t=0 arg=0x80e5ebc
>
<L  >    77012 [TCP/IP    ] tcpip: dns_tmr()
>
<L  >    77012 [TCP/IP    ] dns_tmr: dns_check_entries
>
<L  >    77012 [TCP/IP    ] sys_timeout: 0x20083558 abs_time=78012 handler=dns_tmr arg=0x80e5ebc
>
<L  >    77845 [TCP/IP    ] sct calling h=(fsm_timeout) t=0 arg=0x20084bf0
>
<L  >    77845 [TCP/IP    ] pbuf_alloc(length=24)
>
<L  >    77845 [TCP/IP    ] pbuf_alloc(length=24) == 0x200831b0
>
<L  >    77845 [TCP/IP    ] pbuf_alloc(length=0)
>
<L  >    77845 [TCP/IP    ] pbuf_alloc(length=0) == 0x20082fa0
>
<L  >    77849 [TCP/IP    ] pbuf_free(0x20082fa0)
>
<L  >    77849 [TCP/IP    ] pbuf_free: deallocating 0x20082fa0
>
<L  >    77849 [TCP/IP    ] pppos_write[0]: len=24
>
<L  >    77849 [TCP/IP    ] pbuf_free(0x200831b0)
>
<L  >    77849 [TCP/IP    ] pbuf_free: deallocating 0x200831b0
>
<L  >    77849 [TCP/IP    ] sys_timeout: 0x20083544 abs_time=83849 handler=(fsm_timeout) arg=0x20084bf0
>
<L  >    78012 [TCP/IP    ] sct calling h=dns_tmr t=0 arg=0x80e5ebc
>
<L  >    78012 [TCP/IP    ] tcpip: dns_tmr()
>
<L  >    78012 [TCP/IP    ] dns_tmr: dns_check_entries
>
<L  >    78012 [TCP/IP    ] sys_timeout: 0x20083558 abs_time=79012 handler=dns_tmr arg=0x80e5ebc
>
<L  >    79012 [TCP/IP    ] sct calling h=dns_tmr t=0 arg=0x80e5ebc
>
<L  >    79012 [TCP/IP    ] tcpip: dns_tmr()
>
<L  >    79012 [TCP/IP    ] dns_tmr: dns_check_entries
>
<L  >    79012 [TCP/IP    ] sys_timeout: 0x20083558 abs_time=80012 handler=dns_tmr arg=0x80e5ebc
>
<L  >    80012 [TCP/IP    ] sct calling h=dns_tmr t=0 arg=0x80e5ebc
>
<L  >    80012 [TCP/IP    ] tcpip: dns_tmr()
>
<L  >    80012 [TCP/IP    ] dns_tmr: dns_check_entries
>
<L  >    80012 [TCP/IP    ] sys_timeout: 0x20083558 abs_time=81012 handler=dns_tmr arg=0x80e5ebc
>
<L  >    81012 [TCP/IP    ] sct calling h=dns_tmr t=0 arg=0x80e5ebc
>
<L  >    81012 [TCP/IP    ] tcpip: dns_tmr()
>
<L  >    81012 [TCP/IP    ] dns_tmr: dns_check_entries
>
<L  >    81012 [TCP/IP    ] sys_timeout: 0x20083558 abs_time=82012 handler=dns_tmr arg=0x80e5ebc
>
<L  >    82012 [TCP/IP    ] sct calling h=dns_tmr t=0 arg=0x80e5ebc
>
<L  >    82012 [TCP/IP    ] tcpip: dns_tmr()
>
<L  >    82012 [TCP/IP    ] dns_tmr: dns_check_entries
>
<L  >    82012 [TCP/IP    ] sys_timeout: 0x20083558 abs_time=83012 handler=dns_tmr arg=0x80e5ebc
>
<L  >    83012 [TCP/IP    ] sct calling h=dns_tmr t=0 arg=0x80e5ebc
>
<L  >    83012 [TCP/IP    ] tcpip: dns_tmr()
>
<L  >    83012 [TCP/IP    ] dns_tmr: dns_check_entries
>
<L  >    83012 [TCP/IP    ] sys_timeout: 0x20083558 abs_time=84012 handler=dns_tmr arg=0x80e5ebc
>
<L  >    83849 [TCP/IP    ] sct calling h=(fsm_timeout) t=0 arg=0x20084bf0
>
<L  >    83849 [TCP/IP    ] pbuf_alloc(length=24)
>
<L  >    83849 [TCP/IP    ] pbuf_alloc(length=24) == 0x200831b0
>
<L  >    83849 [TCP/IP    ] pbuf_alloc(length=0)
>
<L  >    83849 [TCP/IP    ] pbuf_alloc(length=0) == 0x20082fa0
>
<L  >    83853 [TCP/IP    ] pbuf_free(0x20082fa0)
>
<L  >    83853 [TCP/IP    ] pbuf_free: deallocating 0x20082fa0
>
<L  >    83853 [TCP/IP    ] pppos_write[0]: len=24
>
<L  >    83853 [TCP/IP    ] pbuf_free(0x200831b0)
>
<L  >    83853 [TCP/IP    ] pbuf_free: deallocating 0x200831b0
>
<L  >    83853 [TCP/IP    ] sys_timeout: 0x20083544 abs_time=89853 handler=(fsm_timeout) arg=0x20084bf0
>
<L  >    84012 [TCP/IP    ] sct calling h=dns_tmr t=0 arg=0x80e5ebc
>
<L  >    84012 [TCP/IP    ] tcpip: dns_tmr()
>
<L  >    84012 [TCP/IP    ] dns_tmr: dns_check_entries
>
<L  >    84012 [TCP/IP    ] sys_timeout: 0x20083558 abs_time=85012 handler=dns_tmr arg=0x80e5ebc
>
<L  >    85012 [TCP/IP    ] sct calling h=dns_tmr t=0 arg=0x80e5ebc
>
<L  >    85012 [TCP/IP    ] tcpip: dns_tmr()
>
<L  >    85012 [TCP/IP    ] dns_tmr: dns_check_entries
>
<L  >    85012 [TCP/IP    ] sys_timeout: 0x20083558 abs_time=86012 handler=dns_tmr arg=0x80e5ebc
>
<L  >    85841 [Tmr Svc   ] ppp_close[0]: kill_link -> lcp_close
>
<L  >    85841 [Tmr Svc   ] ppp phase changed[0]: phase=11
>
<L  >    86012 [TCP/IP    ] sct calling h=dns_tmr t=0 arg=0x80e5ebc
>
<L  >    86012 [TCP/IP    ] tcpip: dns_tmr()
>
<L  >    86012 [TCP/IP    ] dns_tmr: dns_check_entries
>
<L  >    86012 [TCP/IP    ] sys_timeout: 0x20083558 abs_time=87012 handler=dns_tmr arg=0x80e5ebc
>
<INF>    86341 [Tmr Svc   ] client ppp_notify_phase_cb: 11
>
<L  >    86341 [Tmr Svc   ] pbuf_alloc(length=20)
>
<L  >    86341 [Tmr Svc   ] pbuf_alloc(length=20) == 0x200831b0
>
<L  >    86341 [Tmr Svc   ] pbuf_alloc(length=0)
>
<L  >    86341 [Tmr Svc   ] pbuf_alloc(length=0) == 0x20082fa0
>
<L  >    86343 [Tmr Svc   ] pbuf_free(0x20082fa0)
>
<L  >    86343 [Tmr Svc   ] pbuf_free: deallocating 0x20082fa0
>
<L  >    86343 [Tmr Svc   ] pppos_write[0]: len=20
>
<L  >    86343 [Tmr Svc   ] pbuf_free(0x200831b0)
>
<L  >    86343 [Tmr Svc   ] pbuf_free: deallocating 0x200831b0
>
<L  >    86343 [Tmr Svc   ] sys_timeout: 0x20083544 abs_time=92343 handler=(fsm_timeout) arg=0x20084bf0
>
<INF>    86343 [Tmr Svc   ] ppposif_config_timeout_timer_callback
>
<INF>    86344 [Tmr Svc   ] CST: CST_notif_callback (Data Cache event=0)
>
<INF>    86344 [Tmr Svc   ] CST: CST_send_message: data cache 0
>
<INF>    86344 [CellularSe] CST: CST_notif_callback (Data Cache event=0)
>
<INF>    86344 [CellularSe] CST: CST_send_message: data cache 0
>
<INF>    86344 [CellularSe] CST: AUTOM TASK: CST_PPP_CONFIG_ON_GOING_STATE - PPP_CLOSED_EVENT

is there any configuration from NRF9160 side, that we are missing in serial lte modem application.

[dejans]

Hi,

We will look into this internally. I will get back to you probably by the end of this week.

Best regards,
Dejan

[dejans]

Hi,

There is currently no support for PPP in SLM using NCS v2.5.0 but there is Modem Shell sample which supports PPP.

Best regards,
Dejan

[nLorami]

Hi, I suggest to move to nRF Connect SDK 2.6.0 or later
you can see that ppp and CMUX is now supported on SLM from that release

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/releases_and_maturity/releases/release-notes-2.6.0.html#serial-lte-modem  

If problems with that release, please open new ticket. 

[Amol_Chor]

Thanks for reply !!

Could you please share the details for enabling the UART2 for AT commands as well as PPP in configuration?

[nLorami]

Hi

please try in the documentation as follows:

to use UART2
https://developer.nordicsemi.com/nRF_Connect_SDK/doc/2.6.1/nrf/applications/serial_lte_modem/doc/slm_description.html#connecting-with-an-external-mcu

for PPP, you need some config. See this section for example:
https://developer.nordicsemi.com/nRF_Connect_SDK/doc/2.6.1/nrf/applications/serial_lte_modem/doc/nRF91_as_Zephyr_modem.html#nrf91-series-sip-running-slm 

Overall, you find SLM documentation here: 
developer.nordicsemi.com/.../README.html

[Amol_Chor]

Hi,

I have tried the latest SLM version 2.6.1 for PPP support, but I am encountering the same issue mentioned in the NRF9160 logs, unable to obtain an IP address.

I am not receiving the 'conack' from the NRF9160, which is required to set up PPP.

[dejans]

Hi,

In addition to what is mentioned in testing in Linux and since you use NB-IoT network, you could try to do the following:

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

Please let me know if these lines resolve your issue.

Best regards,
Dejan