modem disconnects after a minute

["Juan A. Rubio" <jarubio2001 gmail com>]

Hi,

I have an embedded system (buildroot-based) and I'm using NM 1.20.4
and MM 1.16.4. I have two NM connections configured and I want them
active at startup. One is an ethernet with DHCP and the other is a gsm
connection.

Both connections get activated correctly when the system comes up but
the gsm connection gets deactivated after less than a minute or so
with reason 'new-activation'.

I'm trying to figure out why the gsm disconnects. Note that I've tried
with two different modems (Quectel and Simcom) and the behaviour is
exactly the same.

Any suggestions?

Thanks in advance
Juan

Filtered logs:

Jun 06 14:33:33 buildroot NetworkManager[263]: <info>
[1622990013.3126] modem["cdc-wdm0"]: modem state changed, 'disabled'
--> 'enabling' (reason: user preference)
Jun 06 14:33:33 buildroot NetworkManager[263]: <info>
[1622990013.3342] device (cdc-wdm0): state change: unmanaged ->
unavailable (reason 'managed', sys-iface-state: 'external')
Jun 06 14:33:33 buildroot NetworkManager[263]: <debug>
[1622990013.3725] device[0x1516380] (cdc-wdm0): connectivity state
changed from UNKNOWN to NONE
Jun 06 14:33:33 buildroot NetworkManager[263]: <debug>
[1622990013.3740] device[0x1516380] (cdc-wdm0): connectivity state
changed from UNKNOWN to NONE
Jun 06 14:33:33 buildroot NetworkManager[263]: <debug>
[1622990013.3872] device[0x1516380] (cdc-wdm0):
queue-state[disconnected, reason:none, id:112]: queue state change
Jun 06 14:33:33 buildroot NetworkManager[263]: <info>
[1622990013.3907] device (cdc-wdm0): state change: unavailable ->
disconnected (reason 'none', sys-iface-state: 'managed')
Jun 06 14:33:33 buildroot NetworkManager[263]: <info>
[1622990013.4253] device (cdc-wdm0): state change: disconnected ->
prepare (reason 'none', sys-iface-state: 'managed')
Jun 06 14:33:33 buildroot NetworkManager[263]: <info>
[1622990013.4484] device (cdc-wdm0): state change: prepare ->
need-auth (reason 'none', sys-iface-state: 'managed')
Jun 06 14:33:33 buildroot NetworkManager[263]: <info>
[1622990013.4919] device (cdc-wdm0): state change: need-auth ->
prepare (reason 'none', sys-iface-state: 'managed')
Jun 06 14:33:34 buildroot NetworkManager[263]: <info>
[1622990014.1894] modem["cdc-wdm0"]: modem state changed, 'enabling'
--> 'enabled' (reason: user-requested)
Jun 06 14:33:34 buildroot NetworkManager[263]: <info>
[1622990014.2020] modem["cdc-wdm0"]: modem state changed, 'enabled'
--> 'connecting' (reason: user-requested)
Jun 06 14:33:34 buildroot NetworkManager[263]: <info>
[1622990014.2846] modem["cdc-wdm0"]: modem state changed, 'connecting'
--> 'registered' (reason: unknown)
Jun 06 14:33:34 buildroot NetworkManager[263]: <info>
[1622990014.8606] modem["cdc-wdm0"]: modem state changed, 'registered'
--> 'connected' (reason: user-requested)
Jun 06 14:33:34 buildroot NetworkManager[263]: <info>
[1622990014.8977] device (cdc-wdm0): state change: prepare -> config
(reason 'none', sys-iface-state: 'managed')
Jun 06 14:33:34 buildroot NetworkManager[263]: <info>
[1622990014.9215] device (cdc-wdm0): state change: config -> ip-config
(reason 'none', sys-iface-state: 'managed')
Jun 06 14:33:34 buildroot NetworkManager[263]: <info>
[1622990014.9740] device (cdc-wdm0): state change: ip-config ->
ip-check (reason 'none', sys-iface-state: 'managed')
Jun 06 14:33:35 buildroot NetworkManager[263]: <debug>
[1622990015.0116] device[0x1516380] (cdc-wdm0):
queue-state[secondaries, reason:none, id:164]: queue state change
Jun 06 14:33:35 buildroot NetworkManager[263]: <info>
[1622990015.0156] device (cdc-wdm0): state change: ip-check ->
secondaries (reason 'none', sys-iface-state: 'managed')
Jun 06 14:33:35 buildroot NetworkManager[263]: <debug>
[1622990015.0202] device[0x1516380] (cdc-wdm0): queue-state[activated,
reason:none, id:165]: queue state change
Jun 06 14:33:35 buildroot NetworkManager[263]: <info>
[1622990015.0266] device (cdc-wdm0): state change: secondaries ->
activated (reason 'none', sys-iface-state: 'managed')
Jun 06 14:33:35 buildroot NetworkManager[263]: <debug>
[1622990015.1392] device[0x1516380] (cdc-wdm0): connectivity state
changed from NONE to FULL
Jun 06 14:33:35 buildroot NetworkManager[263]: <debug>
[1622990015.1463] device[0x1516380] (cdc-wdm0): connectivity state
changed from NONE to FULL


               vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
Jun 06 14:34:27 buildroot NetworkManager[263]: <info>
[1622990067.6696] device (cdc-wdm0): state change: activated ->
deactivating (reason 'new-activation', sys-iface-state: 'managed')

               vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv


Jun 06 14:34:27 buildroot NetworkManager[263]: <debug>
[1622990067.7086] device[0x1516380] (cdc-wdm0): connectivity state
changed from FULL to NONE
Jun 06 14:34:27 buildroot NetworkManager[263]: <debug>
[1622990067.7100] device[0x1516380] (cdc-wdm0): connectivity state
changed from FULL to NONE
Jun 06 14:34:27 buildroot NetworkManager[263]: <debug>
[1622990067.7273] device[0x1516380] (cdc-wdm0): state change:
deactivating -> deactivating (reason 'new-activation',
sys-iface-state: 'managed')
Jun 06 14:34:27 buildroot NetworkManager[263]: <info>
[1622990067.8017] modem["cdc-wdm0"]: modem state changed, 'connected'
--> 'disconnecting' (reason: user-requested)
Jun 06 14:34:27 buildroot NetworkManager[263]: <info>
[1622990067.8817] modem["cdc-wdm0"]: modem state changed,
'disconnecting' --> 'registered' (reason: user-requested)
Jun 06 14:34:27 buildroot NetworkManager[263]: <debug>
[1622990067.8874] device[0x1516380] (cdc-wdm0):
queue-state[disconnected, reason:new-activation, id:288]: queue state
change
Jun 06 14:34:27 buildroot NetworkManager[263]: <info>
[1622990067.8881] device (cdc-wdm0): state change: deactivating ->
disconnected (reason 'new-activation', sys-iface-state: 'managed')
Jun 06 14:34:28 buildroot NetworkManager[263]: <info>
[1622990068.0721] device (cdc-wdm0): state change: disconnected ->
prepare (reason 'none', sys-iface-state: 'managed')
Jun 06 14:34:28 buildroot NetworkManager[263]: <info>
[1622990068.1139] device (cdc-wdm0): state change: prepare ->
need-auth (reason 'none', sys-iface-state: 'managed')
Jun 06 14:34:28 buildroot NetworkManager[263]: <info>
[1622990068.1656] device (cdc-wdm0): state change: need-auth ->
deactivating (reason 'user-requested', sys-iface-state: 'managed')
Jun 06 14:34:28 buildroot NetworkManager[263]: <debug>
[1622990068.2152] device[0x1516380] (cdc-wdm0):
queue-state[disconnected, reason:user-requested, id:313]: queue state
change
Jun 06 14:34:28 buildroot NetworkManager[263]: <info>
[1622990068.2166] device (cdc-wdm0): state change: deactivating ->
disconnected (reason 'user-requested', sys-iface-state: 'managed')



For reference (gsm connection):

[connection]
id=bdi_lte
interface-name=cdc-wdm0
autoconnect=true
type=gsm
permissions=
wait-device-timeout=60

[gsm]
apn=""
password=""
username=""

[ipv4]
route-metric=100
dns-search=
method=auto

[ipv6]
addr-gen-mode=stable-privacy
dns-search=
method=auto

[proxy]