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

[Hardik.Harpal]

Any update on previous reply? For JIO network, Gujarat state MNC should be 857

[Hardik.Harpal]

Hi Heidi

Any update, How to resolve APN MNC issue? 

Hoping to resolve soon.

[Heidi]

Hi! We are looking into this and I will get back to you shortly.

[Heidi]

There is no failue in the IMSI encoding. The modem reads the IMSI from the UICC and uses it unmodified in the EPS Mobile Identity IE of the Attach Request. You can see the use MCC + MNC (405 + 857) in the picture:

The decoder tool seems to have a bug that drops the last digit of the MNC, but as you can see the last digit (7) is there. If JIO disagrees, please ask what they think is wrong in the PDU encoding. 

[Heidi]

Hi! 

Were you able to resolve this with JIO network?

[Hardik.Harpal]

They sent new JIO sims now I am able to see registered on network in at_client-link monitor. Let me try on my custom app and let you know. 

[Hardik.Harpal]

New JIO sim working fine. Changed few things, as it supports only IPV6 connectivity.

Thank you Heidi and Nordic for your support.