NB-IOT JIO SIM Not connecting asset tracker Work Up to RRC Connected and stuck there.

[Hardik.Harpal]

Using NB- IOT JIO SIM in india, not connecting asset tracker Work Up to RRC Connected and stuck there. This is custom code very similar to asset tracker example. We are using custom board, same setup works fine on Ibasis SIM in USA.

[00:00:00.215,576] [0m<inf> asset_tracker: Connecting to LTE network.[0m
[00:00:00.215,942] [0m<inf> asset_tracker: This may take several minutes.[0m
[00:00:00.223,205] [0m<dbg> lte_lc.lte_lc_system_mode_set: Sending AT command to set system mode: AT%XSYSTEMMODE=0,1,1,0[0m
[00:00:00.259,643] [0m<inf> lte_lc: PDP Context: AT+CGDCONT=0,"IPV6","JioIPIoT"[0m
[00:00:00.267,608] [0m<dbg> lte_lc.lte_lc_system_mode_set: Sending AT command to set system mode: AT%XSYSTEMMODE=0,1,1,0[0m
[00:00:27.635,711] [0m<dbg> lte_lc.at_handler: +CEREG notification: +CEREG: 2,"C061","00282218",9
[0m
[00:00:27.636,444] [0m<inf> asset_tracker: LTE cell changed: Cell ID: 2630168, Tracking area: 49249[0m

trace-2021-07-13T00-06-58.563Z.pcapng

trace-2021-07-13T00-06-58.563Z.bin

[Heidi]

Hi! Håkon has gone on vacation so I have taken over this case.

The conclusion from the modem trace you provided is that the Attach procedure is prevented due to the modem reset loop restriction feature which was introduced in MFW 1.3.0. We have just released a white paper on the feature which should explain the functionality in detail: nWP042 - nRF9160 Modem Reset Loop Restriction

In short, the feature restricts Attach attempts to the network for 30 minutes in the case where the modem detects that the UE is in a reset loop. This can also happen if the modem is manually reset too many times.

The AT+CFUN = 0 command should be used for shutting down the modem gracefully in order to avoid this restriction. 

Please let me know if this solves the issue you are seeing. 

Best regards,

Heidi

[Hardik.Harpal]

Hi,

But I am seeing similar results in Modem firmware version 1.2.3 and earlier version on Dev kit I have 1.2.3 let me send you modem log from it. I will use MQTT simple example and configure it for nbiot.

Can AT_Client example running with link monitor can provide modem trace by default or do I have to change prj config changes to enable it?

Can you analyze this  new log withing next 22 hours? I have meeting with  JIO support team. If anything from their side I can provide our observation from Log they're asking for more detailed modem log as I explained in previous replies, I shared same modem trace (wireshark playable) with them. There are higher chances it is from network, but we need to figure it out as it is a month long now.

Regards,

Hardik Harpal

[Heidi]

Hardik.Harpal said:

Can AT_Client example running with link monitor can provide modem trace by default or do I have to change prj config changes to enable it?

 The AT Client sample does not have the correct config enabled by default, you have to add CONFIG_NRF_MODEM_LIB_TRACE_ENABLED=y to the prj.conf file.

Hardik.Harpal said:

Can you analyze this  new log withing next 22 hours?

 I am dependent on the schedule of the modem team, but if you provide me the trace within the next hour they should have enough time to analyze it by tomorrow morning. 

Unfortunately, the converted modem logs are only for use internally in Nordic so I can't provide the converted file, but I will try to provide the relevant information (LTE Physical, MAC, RRC, NAS signaling).

Best regards,

Heidi

[Hardik.Harpal]

Application: mqtt_simple, modem FW:1.2.3, board: nrf91DK, NCS1.6.0

5808.mqtt_simple.rar

Application Log:

16:01:22.338, *** Booting Zephyr OS build v2.6.0-rc1-ncs1 ***
16:01:23.337, [00:00:00.212,249] [0m<inf> mqtt_simple: The MQTT simple sample started[0m
16:01:23.448, [00:00:00.218,902] [0m<inf> mqtt_simple: Disabling PSM and eDRX[0m
16:01:23.448, [00:00:00.219,696] [0m<inf> mqtt_simple: LTE Link Connecting...[0m
16:02:17.323, +CEREG: 2,"C057","00094218",9,0,0,"11100000","11100000"
16:02:17.445, +CSCON: 1
16:02:17.666, +CEREG: 0,"C057","00094218",9,0,8,"11100000","11100000"
16:02:17.666, +CSCON: 0

trace-2021-08-03T10-44-01.054Z.pcapng

trace-2021-08-03T10-44-01.054Z.bin

[Hardik.Harpal]

Heidi Any update?

[Heidi]

There are a lot of traces lost during decoding, which isn't something we've seen before. Unfortunately, our tracing tool experts aren't back to work until next week.

The last NAS level trace shows that it is requesting RRC connection establishment for the Attach Request which was not the case in MFW 1.3.0 in which Attach procedure was blocked due to reset loop restriction.