Slice SD with hexadecimal digits

Q/A
#1

I’m trying the slicing functionality with free5gc-compose.
It seems that the AMF does not work if the SD parameter of a slice contains a hexadecimal digit that is not a decimal digit.

This bug can be reproduced with the following steps:

  1. Checkout free5gc-compose commit 75e86d37.
  2. Modify docker-compose.yaml, changing the chf image from v3.3.0 to latest, because v3.3.0 is not published on Docker Hub.
  3. Replace all occurrences of 010203 in config/ folder to 01020a:
    git grep -l 010203 config/ | xargs sed -i 's/010203/01020A/g'
  4. Run docker compose up -d to start the scenario.
  5. Open web console in a browser, click New Subscriber, change 010203 to 01020a, keep everything else, and submit.
  6. Run docker exec -it ueransim ./nr-ue -c ./config/uecfg.yaml -i 208930000000003.

The UE prints this error:

[2023-10-27 18:13:31.098] [nas] [info] Initial Registration is successful
[2023-10-27 18:13:31.098] [nas] [debug] Sending PDU Session Establishment Request
[2023-10-27 18:13:31.098] [nas] [debug] UAC access attempt is allowed for identity[0], category[MO_sig]
[2023-10-27 18:13:31.307] [nas] [error] SM forwarding failure for message type[193] with cause[DNN_NOT_SUPPORTED_OR_NOT_SUBSCRIBED]
[2023-10-27 18:13:31.307] [nas] [debug] Aborting SM procedure for PTI[1], PSI[1]
[2023-10-27 18:13:32.127] [nas] [debug] Sending PDU Session Establishment Request
[2023-10-27 18:13:32.127] [nas] [debug] UAC access attempt is allowed for identity[0], category[MO_sig]
[2023-10-27 18:13:32.132] [nas] [error] SM forwarding failure for message type[193] with cause[DNN_NOT_SUPPORTED_OR_NOT_SUBSCRIBED]
[2023-10-27 18:13:32.132] [nas] [debug] Aborting SM procedure for PTI[1], PSI[1]

The AMF prints this error:

2023-10-27T18:13:31.301236992Z [INFO][AMF][Gmm][amf_ue_ngap_id:RU:1,AU:1(3GPP)][supi:SUPI:imsi-208930000000003] Transport 5GSM Message to SMF
2023-10-27T18:13:31.301248563Z [INFO][AMF][Gmm][amf_ue_ngap_id:RU:1,AU:1(3GPP)][supi:SUPI:imsi-208930000000003] Select SMF [snssai: {Sst:1 Sd:01020a}, dnn: internet]
2023-10-27T18:13:31.305223576Z [WARN][AMF][Gmm][amf_ue_ngap_id:RU:1,AU:1(3GPP)][supi:SUPI:imsi-208930000000003] nsiInformation is still nil, use default NRF[http://nrf.free5gc.org:8000]
2023-10-27T18:13:31.307068595Z [ERRO][AMF][Gmm][amf_ue_ngap_id:RU:1,AU:1(3GPP)][supi:SUPI:imsi-208930000000003] Select SMF failed: DNN[internet] is not supported or not subscribed in the slice[Snssai: {Sst:1 Sd:01020a}]

I tried several different SD values.
I found that the AMF only works if the SD value consists of solely decimal digits /[0-9]{6}/.
If any digit is /[A-F]/, the above errors would occur.

#2

Hi @yoursunny,
this seems like an uppercase/lowercase issue. Try to use lowercase for SD in the webconsole and configs. This is because free5gc-compose is using v3.3.0, if using the latest version of NFs, it doesn’t matter whether uppercase or lowercase is been used. If there’s still any issue, please let me know.

BRs,
linpoyi

#3

Indeed.
I retested with:

git grep -l 010203 config/ | xargs sed -i 's/010203/01020a/g'

The UE registers successfully and the PDU session works.

#4