During tests with a "User controlled PLMN selector with Access Technology '6F60'" one device stuck in a curious state:
nRF9160 SICA B0A
mfw v1.3.3
CAT-M1, PSM: PTAU 24h, Act 0s
SIM-Card: user HPPLMN 26202 interval: 10h
Message exchanges every 60min.
PLMN: "26203","E936",7,20,"01656201"
(Console log, trace not enabled and so not available)
[05:57:49.511,749] <inf> COAP_CLIENT: Network registration status: Searching ...
[05:57:49.511,810] <inf> COAP_CLIENT: LTE cell changed: Cell ID: -1, Tracking area: -1
[05:57:49.511,871] <inf> COAP_CLIENT: LTE Mode: none
[05:57:49.771,057] <inf> COAP_CLIENT: Network registration status: Connected - roaming network
[05:57:49.771,087] <inf> COAP_CLIENT: LTE cell changed: Cell ID: 23421441, Tracking area: 59702
[05:57:49.772,674] <inf> COAP_CLIENT: LTE Mode: CAT-M1
[05:57:49.916,839] <inf> COAP_CLIENT: modem ready.
[05:57:49.916,870] <inf> COAP_CLIENT: RRC mode: Connected
[05:57:49.917,724] <inf> COAP_CLIENT: XMONITOR: 5,"","","26203","E936",7,20,"01656201",151,6200,21,26,"","11100000","11100000","01011110"
[05:57:49.918,365] <inf> COAP_CLIENT: CEINFO: 0,1,R,8,4,-120,1
[05:57:49.919,189] <inf> COAP_CLIENT: modem signaled ready.
[05:57:52.215,362] <inf> COAP_CLIENT: modem not ready. con=0/pdn=1/reg=1
[05:57:52.215,423] <inf> COAP_CLIENT: RRC mode: Idle after 2299 ms
[05:58:01.801,513] <inf> COAP_CLIENT: CoAP wait state 0, 28
[05:58:07.431,396] <inf> COAP_CLIENT: Network registration status: Searching ...
[05:58:07.431,457] <inf> COAP_CLIENT: LTE cell changed: Cell ID: -1, Tracking area: -1
[05:58:07.431,518] <inf> COAP_CLIENT: LTE Mode: none
[05:58:07.911,651] <inf> COAP_CLIENT: Network registration status: Connected - roaming network
[05:58:07.911,682] <inf> COAP_CLIENT: LTE cell changed: Cell ID: 23421441, Tracking area: 59702
[05:58:07.913,238] <inf> COAP_CLIENT: LTE Mode: CAT-M1
[05:58:08.061,370] <inf> COAP_CLIENT: modem ready.
[05:58:08.061,401] <inf> COAP_CLIENT: RRC mode: Connected
[05:58:08.062,286] <inf> COAP_CLIENT: XMONITOR: 5,"","","26203","E936",7,20,"01656201",151,6200,23,21,"","11100000","11100000","01011110"
[05:58:08.062,896] <inf> COAP_CLIENT: CEINFO: 0,1,R,8,4,-118,-4
[05:58:08.063,751] <inf> COAP_CLIENT: modem signaled ready.
[05:58:10.308,898] <inf> COAP_CLIENT: modem not ready. con=0/pdn=1/reg=1
[05:58:10.308,959] <inf> COAP_CLIENT: RRC mode: Idle after 2247 ms
[05:58:25.352,783] <inf> COAP_CLIENT: Network registration status: Searching ...
[05:58:25.352,844] <inf> COAP_CLIENT: LTE cell changed: Cell ID: -1, Tracking area: -1
[05:58:25.352,874] <inf> COAP_CLIENT: LTE Mode: none
[05:58:28.532,257] <inf> COAP_CLIENT: Network registration status: Connected - roaming network
[05:58:28.532,318] <inf> COAP_CLIENT: LTE cell changed: Cell ID: 23421441, Tracking area: 59702
[05:58:28.533,874] <inf> COAP_CLIENT: LTE Mode: CAT-M1
[05:58:28.661,987] <inf> COAP_CLIENT: modem ready.
[05:58:28.662,048] <inf> COAP_CLIENT: RRC mode: Connected
[05:58:28.662,902] <inf> COAP_CLIENT: XMONITOR: 5,"","","26203","E936",7,20,"01656201",151,6200,23,23,"","11100000","11100000","01011110"
[05:58:28.663,543] <inf> COAP_CLIENT: CEINFO: 0,1,R,8,4,-118,-2
[05:58:28.664,367] <inf> COAP_CLIENT: modem signaled ready.
[05:58:30.937,530] <inf> COAP_CLIENT: modem not ready. con=0/pdn=1/reg=1
[05:58:30.937,591] <inf> COAP_CLIENT: RRC mode: Idle after 2276 ms
[05:53:36.796,630] <inf> COAP_CLIENT: received_from_peer 41 bytes
[05:53:36.796,661] <inf> TINYDTLS: received message (41 bytes), starting with 'application_data', epoch 1
[05:53:36.796,691] <inf> TINYDTLS: got 'application_data' epoch 1 sequence 46 (41 bytes)
[05:53:36.796,905] <inf> TINYDTLS: ** application data:
it executes every 18s a network search. By the way, it was able to exchange data with the server.
Finally it switched to
PLMN "26201","67B9",7,20,"01CC2B03"
and the searches are stopped.
At that point, 1643 network searches has been reached and 1057s has been spend in searching. Without changing the PLMN nor even the Cell.
(For now, I don't plan further investigations. That's too time consuming.)
