Unable to change APN

RE: Unable to change APN

Terje K Wahl — Fri, 25 Oct 2019 07:44:54 GMT

Success! I Network traffic now works.

The problem turned out to be the network provider not having configured my SIM card/subscription to allow it to use NB-IoT. And also not telling me about this the first time I contacted them...

After this configuration change with the network provider, the correct APN is automatically used for context CID 0. I tested however with CID 1 also, and activating CID 1 and deactivating CID 0 now also works.

My conclusion: Error message "+CNEC_ESM: 65,1" - "Maximum number of EPS bearers reached" - indicated a problem with the cellular subscription configuration.

Thank you for your help.

Kind regards,

Terje

RE: Unable to change APN

Terje K Wahl — Thu, 24 Oct 2019 13:13:53 GMT

Hi,

Thank you for your support.

I have now been in contact with the network provider, and they have changed my SIM/subsription settings for it to work on NB-IoT. And now I am able to get an IP address "automagically" for the correct APN when connecting to the network! So the error message was related to carrier configuration/limitations.

I am a bit annoyed that my network provider did not told me this needed to be done for it to work on NB-IoT before when I contacted them... But anyway, it now looks promising.

I will test tomorrow if network traffic now finally works.

RE: Unable to change APN

Didrik Rokhaug — Thu, 24 Oct 2019 13:08:07 GMT

Hi.

I am out of ideas at the moment but have requested help from our modem team.

They will probably want a modem trace to help identify what is going on.

Can you take a modem trace where you override the default APN (CGDCONT=0, ...) before turning on the modem (similar to your first log from the at_client), and upload the trace together with the application log?

If you want to, you can also do the same where you are using a different PDN context.

If you do not know how to take a modem trace, you can follow this guide: https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/how-to-get-modem-trace-using-trace-collector-in-nrf-connect

Best regards,

Didrik

RE: Unable to change APN

Terje K Wahl — Thu, 24 Oct 2019 11:38:23 GMT

Hi and thanks for the suggestions.

When trying to activate a second APN after being attached to the network ("AT+CGACT=1,1"), I receive an error "ERROR" and error code "+CNEC_ESM: 65,1". According to 3GPP TS 24.301 Table 9.9.4.4.1 for EPS session management errors codes, error code 65 means "Maximum number of EPS bearers reached".

I double checked the device is in NB-IoT mode (as shown in the log below), and AT%XMONITOR seems to return sensible values as far as I can tell (shown in log below).

I'm not quite sure what to make of the "Maximum number of EPS bearers reached" error (I've tried searching for it), so more help would be great.

To summarize so far: I am able to connect to the cellular network and I am even assigned an IP address on CID 0 with APN "com4". However, data traffic won't work and when I speak to the network provider (Com4 in Norway) they tell me I need to use APN "iot.com4.net". However there is a limitation in the nRF9160 so I'm not able to replace CID 0 but have to create an additional CID 1 with the different APN. However when trying to activate CID 1 an error is returned (as mentioned above).

Is this a limitation in the nRF9160 or a limitation with the network provider? Or are they just not compatible (yet)? Are there other things I can try?

Log from AT Client:

***** Booting Zephyr OS v1.14.99-ncs2 *****
The AT host sample started
AT
OK
AT%XSYSTEMMODE?
%XSYSTEMMODE: 0,1,1,0
OK
AT+CFUN?
+CFUN: 4

OK
AT+CGDCONT=1,"IP","iot.com4.net"
OK
AT+CGDCONT?
+CGDCONT: 1,"IP","iot.com4.net","",0,0
OK
AT+CFUN=1
OK
AT+CFUN?
+CFUN: 1
OK
AT+CGSN=1
+CGSN: "352656100223414"
OK
AT+CGMI
Nordic Semiconductor ASA
OK
AT+CGMM
nRF9160-SICA
OK
AT+CGMR
mfw_nrf9160_1.0.1
OK
AT+CEMODE?
+CEMODE: 0
OK
AT%XCBAND=?
%XCBAND: (1,2,3,4,5,8,12,13,17,19,20,25,26,28,66)
OK
AT+CMEE?
+CMEE: 0
OK
AT+CMEE=1
OK
AT+CNEC?
+CNEC: 0
OK
AT+CNEC=24
OK
AT+CGEREP?
+CGEREP: 0,0
OK
AT+CGDCONT?
+CGDCONT: 1,"IP","iot.com4.net","",0,0
OK
AT+CGACT?
+CGACT: 1,0
OK
AT+CGEREP=1
OK
AT+CIND=1,1,1
OK

AT+CEREG=2
OK
AT+CEREG?
+CEREG: 2,"0CEB","0202791C",9
+CEREG: 2,2,"0CEB","0202791C",9
OK
AT%CESQ=1
OK
AT+CESQ
+CESQ: 99,99,255,255,255,59
OK
AT%XSIM=1
OK
AT%XSIM?
%XSIM: 1
OK
AT+CPIN?
+CPIN: READY
OK
AT+CPINR="SIM PIN"
+CPINR: "SIM PIN",3
OK
AT+CIMI
242090000457851
OK
+CGEV: ME PDN ACT 0,0
+CNEC_ESM: 50,0
+CEREG: 1,"0CEB","0202791C",9
+CIND: "service",1
AT+CGDCONT?
+CGDCONT: 0,"IP","com4","100.64.66.80",0,0
+CGDCONT: 1,"IP","iot.com4.net","",0,0
OK

AT+COPS=3,2
OK
AT+CGACT?
+CGACT: 0,1
+CGACT: 1,0
OK
AT+COPS?
+COPS: 0,2,"24202",9
OK
AT%XCBAND
%XCBAND: 20
OK
AT+CGDCONT?
+CGDCONT: 0,"IP","com4","100.64.66.80",0,0
+CGDCONT: 1,"IP","iot.com4.net","",0,0
OK
AT+CGACT?
+CGACT: 0,1
+CGACT: 1,0
OK
AT+CFUN?
+CFUN: 1
OK
AT+CGSN=1
+CGSN: "352656100223414"
OK
AT+CGMI
Nordic Semiconductor ASA
OK
AT+CGMM
nRF9160-SICA
OK
AT+CGMR
mfw_nrf9160_1.0.1
OK
AT+CEMODE?
+CEMODE: 0
OK
AT%XCBAND=?
%XCBAND: (1,2,3,4,5,8,12,13,17,19,20,25,26,28,66)
OK
AT+CMEE?
+CMEE: 1
OK
AT+CNEC?
+CNEC: 24
OK
AT+CGEREP?
+CGEREP: 1,0
OK
AT+CIND=1,1,1
OK
AT+CEREG=2
OK

AT+CEREG?
+CEREG: 2,1,"0CEB","0202791C",9
OK
AT+COPS=3,2
OK
AT+COPS?
+COPS: 0,2,"24202",9
OK
AT%XCBAND
%XCBAND: 20
OK

AT+CGDCONT?
+CGDCONT: 0,"IP","com4","100.64.66.80",0,0
+CGDCONT: 1,"IP","iot.com4.net","",0,0
OK
AT+CGACT?
+CGACT: 0,1
+CGACT: 1,0
OK
AT%CESQ=1
OK
AT+CESQ
+CESQ: 99,99,255,255,255,59
OK
AT%XSIM=1
OK
AT%XSIM?
%XSIM: 1
OK
AT+CPIN?
+CPIN: READY
OK
AT+CPINR="SIM PIN"
+CPINR: "SIM PIN",3
OK
AT+CIMI
242090000457851
OK
AT+CGACT=1,1
ERROR
+CNEC_ESM: 65,1

AT%XMONITOR
%XMONITOR: 1,"Telia","Telia","24202","0CEB",9,20,"0202791C",31,6254,59,29,"","11100000","11100000"
OK
AT+CGDCONT?
+CGDCONT: 0,"IP","com4","100.64.66.80",0,0
+CGDCONT: 1,"IP","iot.com4.net","",0,0
OK
AT+CGACT=1,1
ERROR
AT+CGACT=0,0
ERROR
AT+CGDCONT?
+CGDCONT: 0,"IP","com4","100.64.66.80",0,0
+CGDCONT: 1,"IP","iot.com4.net","",0,0
OK
AT+CGACT?
+CGACT: 0,1
+CGACT: 1,0
OK

Kind regards,

Terje

RE: Unable to change APN

Didrik Rokhaug — Wed, 23 Oct 2019 08:49:21 GMT

Hi.

According to our modem team, you will not be able to activate a second APN until you are attached to the network.

Also, you to make sure, have you remembered to change to NB-IoT mode?

What is the result of AT%XMONITOR?

Best regards,

Didrik

RE: Unable to change APN

Terje K Wahl — Tue, 22 Oct 2019 12:56:14 GMT

Hi,

I have gotten a suggestion to try to use context ID (CID) 1 for the new APN, but now I don't know how to specify that the modem should use CID 1 in stead of CID 0.

Using the command AT+CGACT=1,1 only returns error messages, and I have tried both in online and flight mode (CFUN=4 and 1):

The AT host sample started
AT
OK
AT+CGDCONT=1,"IP","iot.com4.net"
OK
AT+CGDCONT=0,"IP","com4"
OK
AT+CGACT=1,1
ERROR
AT+CGACT=0,0
ERROR
AT+CFUN=1
OK
AT+CGACT=1,1
ERROR
AT+CGDCONT?
+CGDCONT: 0,"IP","com4","100.64.93.245",0,0
+CGDCONT: 1,"IP","iot.com4.net","",0,0
OK

How do I specify that the modem should use context ID 1?

Thank you for your help.

RE: Unable to change APN

Terje K Wahl — Fri, 18 Oct 2019 11:46:38 GMT

Hi,

Thanks for the tips, but I have allready done this.

When setting CONFIG_LTE_PDP_CONTEXT in the configuration file I used backslash to escape the quote characters. When sending AT commands directly I do not escape the quotation marks because then it is (as far as I know) not right to do so.

Either way, when reading back the PDP context from the modem it appears to return the correct string with quotation marks:

AT+CGDCONT?
+CGDCONT: 0,"IP","iot.com4.net","",0,0
OK

Other suggestions are welcome 🙂

RE: Unable to change APN

Amanda Hsieh — Fri, 18 Oct 2019 11:39:02 GMT

Hi,

Since the APN has quotes in it, you need to explicitly set this as \":

CONFIG_LTE_PDP_CONTEXT="1,\"IP\",\"test\""

This will end up as:

AT+CGDCONT?
+CGDCONT: 0,"IPV4V6","telenor.iot","10.111.223.35 2A02:2121:0048:8B27:0000:001A:DCA1:2701",0,0
+CGDCONT: 1,"IP","test","",0,0
OK

-Amanda H.