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modem trace software questions

io22m007

Hello all,

I'm using a nRF9160 DK for a project and I have a few questions regarding modem trace software.

  1. Is there a way to process modem traces on ARM devices such as Raspberry Pi or other single board computers? The only ways I have found to process modem traces from the bin or mtrace format into the pcapng format is with either nRF Connect Cellular Monitor or with nRF Util trace command which are only available for devices with Intel/AMD/Apple processors.
  2. Does the following note on the Cellular: Modem Shell page refer to the now deprecated nRF Connect Trace Collector or an upcoming feature in Memfault or another software/tool:
    "The conversion of modem trace file to a Wireshark-compatible format will be available in one of the future releases of the Trace Collector tool."
  3. I've been looking for documentation on the modem trace format (bin/mtrace) but wasn't able to find anything on this so far. Does public documentation on the bin/mtrace format exist or would Nordic be able to share this documentation? The AT command requests and responses are included in plain text and the NAS and SIB Messages are included in the same format as they are communicated over the network. It would be great to know what the other bytes which sit in-between are for or at least with which bits or bytes AT command requests and responses as well as NAS and SIB messages start and end to be able to extract this information.
  4. What is the purpose of the trace-db.json in nRF Connect Cellular Monitor?


I would appreciate it if someone could help me with these questions.

Thanks in advance!

regards,

Florian

  • 0

    Hi,

    Is there a way to process modem traces on ARM devices such as Raspberry Pi or other single board computers? The only ways I have found to process modem traces from the bin or mtrace format into the pcapng format is with either nRF Connect Cellular Monitor or with nRF Util trace command which are only available for devices with Intel/AMD/Apple processors.

    The only tools we have for decoding modem traces are the Cellular Monitor and nRF Util.

    May I ask why you want to decode the traces on a single board computer?

    You can always use the single board computer to capture the trace, and then decode it and analyze it on a bigger laptop

    Does the following note on the Cellular: Modem Shell page refer to the now deprecated nRF Connect Trace Collector or an upcoming feature in Memfault or another software/tool:
    "The conversion of modem trace file to a Wireshark-compatible format will be available in one of the future releases of the Trace Collector tool."

    Yes, that is probably referring to the now deprecated Trace Collector (v1).

    I'll see if we can update the documentation.

    I've been looking for documentation on the modem trace format (bin/mtrace) but wasn't able to find anything on this so far. Does public documentation on the bin/mtrace format exist or would Nordic be able to share this documentation? The AT command requests and responses are included in plain text and the NAS and SIB Messages are included in the same format as they are communicated over the network. It would be great to know what the other bytes which sit in-between are for or at least with which bits or bytes AT command requests and responses as well as NAS and SIB messages start and end to be able to extract this information.

    No, the modem trace format is not publicly documented.

    AT commands, and NAS and SIB messages should be included in the .pcap generated by the Cellular Monitor or nRF Util.

    However, there is more information in the modem traces that we do not want to/cannot share. But, if you have a problem that you cannot solve based on the public information alone, you can open a new ticket here at DevZone, and we can analyze the raw trace to help solve the issue.

    What is the purpose of the trace-db.json in nRF Connect Cellular Monitor?

    The trace DBs are used to decode the trace.

    Best regards,

    Didrik

  • 0 in reply to Didrik Rokhaug

    Hi Didrik,

    thank you very much for the reply!

    Didrik Rokhaug said:

    The only tools we have for decoding modem traces are the Cellular Monitor and nRF Util.

    May I ask why you want to decode the traces on a single board computer?

    You can always use the single board computer to capture the trace, and then decode it and analyze it on a bigger laptop

    Thank you for confirming that Cellular monitor and nRF Util are the only two options Nordic provides to decode modem traces. 

    -> As a follow up question is it possible to use tshark or Wireshark cli with nRF Util on Linux instead of Wireshark desktop? I suspect it would be.

    The intension would be to import the decoded trace data (AT Commands, NAS, SIB) into a custom server-based solution in real time while the nRF9160 DK is moved around (outdoor) to enable real time remote monitoring. It would be great to use an ARM powered single-board computer for this since they are small and can be powered with most power banks.

    I've already come across the option to save the traffic of the trace COM port into a bin file and then decode it with Cellular monitor or nRF Util.

    Didrik Rokhaug said:

    Yes, that is probably referring to the now deprecated Trace Collector (v1).

    I'll see if we can update the documentation.

    Yes, it would be great if you could update the documentation in this regard.

    Didrik Rokhaug said:

    No, the modem trace format is not publicly documented.

    AT commands, and NAS and SIB messages should be included in the .pcap generated by the Cellular Monitor or nRF Util.

    However, there is more information in the modem traces that we do not want to/cannot share. But, if you have a problem that you cannot solve based on the public information alone, you can open a new ticket here at DevZone, and we can analyze the raw trace to help solve the issue.

    Thank you for confirming that there is no public documentation for the modem trace format.

    This means that there is little to no chance that Nordic would be willing to share the full format of an AT Command request/response and NAS/SIB message in the bin or mtrace files. With full format I mean the start and end sequence of such entries and the relative timestamp. If these entries contain fields which are not in the pcapng file (Nordic internal) specify how many bit/byte to skip.

    I understand that you don't want to disclose information regarding the parts of the modem trace files which are only meant for Nordic internal use (so not part of a modem trace converted into a pcapng file).

    Didrik Rokhaug said:

    The trace DBs are used to decode the trace.

    Thank you for this information.

    Another option I could think of would be the use of unsolicited AT command messages that would pass the NAS/SIB messages to the serial console COM Port along with the other AT command responses. I don't think this is currently an option in either the standard AT command set, nor the expanded Serial LTE Modem application AT command set.

    Also, I accidentally closed the ticket temporarily since I didn't know that is what the Verify Answer button is used for. I think it should be open again. Apologies if this causes any issues.

    Best regards,

    Florian

  • 0 in reply to io22m007
    io22m007 said:
    As a follow up question is it possible to use tshark or Wireshark cli with nRF Util on Linux instead of Wireshark desktop? I suspect it would be.

    I don't have any experience with tshark myself, but I don't see why it shouldn't be able to read the .pcap files produced by nRF Util.

    io22m007 said:
    Yes, it would be great if you could update the documentation in this regard.

    https://github.com/nrfconnect/sdk-nrf/pull/11794

  • 0 in reply to Didrik Rokhaug
    Didrik Rokhaug said:
    github.com/.../quote]

    Thanks for the pull request.

    Didrik Rokhaug said:

    I don't have any experience with tshark myself, but I don't see why it shouldn't be able to read the .pcap files produced by nRF Util.

    In my question I was tiring to refer to the option to pipe from nRF Util into a Wireshark executable and if instead the trace could be piped into tshark or similar cli application.

    [/quote]
  • 0 in reply to io22m007

    Unfortunately, I haven't tried this, and I don't know enough about the internals of Wireshark, tshark or nRF Util to give a proper answer.

    https://infocenter.nordicsemi.com/topic/ug_nrfutils/UG/nrfutils/nrfutil_trace_formats.html

    If tshark is similar enough to Wireshark, you might be able to give the path to tshark instead of Wireshark, and it will "just work".

    Or, if tshark can read a file that is being written to, you can output the trace to a .pcap, and have tshark read from that file.

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