5G NR RRC Sniffing shows only UDP packets in Wireshark

[Sugarless-tchen]

Hello,
First of all, thank you for providing such a practical and valuable tool.
From Web I found that that QCSuper v2 has successfully captured NR RRC frames on certain 5G devices, which is really exciting.

I tried to sniff 5G CPE signaling during the attach procedure to a 5G SA network using the USB DIAG interface.
However, in Wireshark, all the captured signaling logs appear as UDP packets instead of decoded NR RRC messages.

(I have another CPE that NR RRC Packet Version is 24)

I would like to ask whether this issue might be related to:

• QCSuper compatibility or support limitation (e.g. Qualcomm NR RRC packet version too new), or
• Wireshark dissector issue (perhaps the plugin cannot decode this particular NR RRC format).
• Whether QCSuper currently supports NR RRC capture and decoding on SDX65-based devices?

Environment
Module: SRM826W
Baseband Chip: Qualcomm SDX65
OS: Windows 11
QCSuper Version: 2.0.1
Network Type: 5G SA
Capture Method: USB DIAG

For reference, I have attached both the .dlf and .pcap capture files.
meig_SA_5G_Pcap.zip
meig_SA_5G_DLF.zip

If you could kindly reply to this issue, I would really appreciate it.
Thanks again for your excellent work on QCSuper!

[arifkyi]

Hello Sugarless-tchen,

if this is 5G SA
If you want to decode real-time with 5G SA, then

you need to use SCAT and then use this repositroy:
https://github.com/arifkyi/5GLuafile
for how to do there is a YT video there, and follow video pre-requisites if there is any

If you want to decode manually,

use this script, and if you dont know which dissector that you want to decode, then you can choose all to try all loop
https://github.com/arifkyi/5GDecoder
there is also Youtube as a hints:
for example in the frame 8 of your PCAP, i tried to decode with all sector, then it will looks like this below
attached.

20251207220237_decoded_output.txt

./5GDecoder.sh
/5GDecoder.sh
Usage: ./5GDecoder.sh <hex_string> [dissector_name or number (1-18)]
Available dissectors:

1. nr-rrc.bcch.bch
2. nr-rrc.bcch.dl.sch
3. nr-rrc.dl.ccch
4. nr-rrc.dl.dcch
5. nr-rrc.pcch
6. nr-rrc.ul.ccch
7. nr-rrc.ul.ccch1
8. nr-rrc.ul.dcch
9. nr-rrc.sbcch.sl.bch
10. nr-rrc.scch
11. nr-rrc.ueradiopaginginformation
12. nr-rrc.ueradioaccesscapabilityinformation
13. nr-rrc.rrc_reconf
14. nr-rrc.uemrdccapability
15. nr-rrc.uennrcapability
16. nr-rrc.radiobearerconfig
17. nas-5gs
18. mac-nr
19. all

./5GDecoder.sh 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 19

the result here --> 20251207220237_decoded_output.txt

[arifkyi]

additional info, for the 5G SA is under GSMTAPv3 which is the still in the draft phase till know,
https://gitea.osmocom.org/peremen/gsmtapv3

that;s why that LUA script https://github.com/arifkyi/5GLuafile is just to mitigate that before the GSMTAPv3 release officially
in Wireshark

[Sugarless-tchen]

Hi arifkyi,

Thank you for providing the useful information about 5G signaling analysis tools. I had already seen your sharing elsewhere and tried some of those tools, especially SCAT.

I encountered an issue with the 5G NR RRC Packet version when using SCAT 1.4.0, but it looks like the problem has been resolved in the recently released SCAT 2.0.0. So for now, I’m considering using SCAT.

Again, thank you very much!