Assistance Required for Free5GC Integration Project

Kumarsatyam1 · January 9, 2024, 3:40pm

Hallo everyone,

My project involves integrating an Amarisoft 5G Base Station with the 5G Core Implementation Free5GC. I need your help with integrating it with the Amari Callbox Classic at gNB side. I have followed the installation documentation of Free5gc. Could you please take a look at the image and confirm whether I am on the right track or if I have taken the wrong path?

At free5GC at AMF I put 192.168.50.20(Amari Callbox IP ) and # 127.0.1.100 is this correct or I should keep default as 192.168.56.101 and 127.0.0.1

Upon attempting to modify the IMSI provided by the Amarisoft test SIM Card, PLMN : 00101, I encountered the following errors:

[2023-10-24 15:18:16.521] [nas] [error] No PLMN could be selected among [1] PLMNs
[2023-10-24 15:18:18.723] [nas] [error] No PLMN could be selected among [1] PLMNs.
ERROR: Field ‘imeiSv’ is tI kindly request your assistance with resolving these issues. I hope you can provide guidance.

Thank you,
Kumar Satyam

Leon777-coder · January 9, 2024, 3:40pm

Hello, this is Leon:

Your image looks fine, based on your description, it seems like is because your PLMN number doesn’t match with your UE. You should go to the yaml config file and change the PLMN number based on your corresponding UE.

Kumarsatyam1 · January 9, 2024, 3:40pm

Hi Leon,

We received the Test SIM Card from Amarisoft, so the PLMN number is 00101. Currently, a significant issue has arisen: there is no NGAP connection between the AMF and RAN/gNB.

If you have any insights into this matter, please feel free to share your comments.

Thank you for your prompt reply.

Leon777-coder · January 9, 2024, 3:40pm

Hello:
This is the image I have from your graph.

Did you see the N2 interface and AMF and Ran gNB?
Can you please double-check whether these IPs were set correctly or not?
And also, can you please double-check whether the RAN PLMN number and Core PLMN are the same or not?
In order to have a successful connection, we need to have the Core, RAN, and Webconsole UE have the same PLMN ID.

Kumarsatyam1 · January 9, 2024, 3:40pm

So, I have Configured between them now some errors are coming after running ./run.sh in free5gc like:
2023-11-15T18:33:55.984499039Z [INFO][AMF][Ngap] [AMF] SCTP Accept from: 192.168.50.20:45354
2023-11-15T18:33:55.986153160Z [INFO][AMF][Ngap] Create a new NG connection for: 192.168.50.20:45354
2023-11-15T18:33:55.987114432Z [INFO][AMF][Ngap][ran_addr:192.168.50.20:45354] Handle NGSetupRequest
2023-11-15T18:33:55.987250665Z [WARN][AMF][Ngap][ran_addr:192.168.50.20:45354] NG-Setup failure: Cannot find Served TAI in AMF
2023-11-15T18:33:55.987439529Z [INFO][AMF][Ngap][ran_addr:192.168.50.20:45354] Send NG-Setup failure
2023-11-15T18:33:55.989621298Z [INFO][AMF][Ngap] Handle SCTP Notification[addr: 192.168.50.20:45354]
2023-11-15T18:33:55.989969712Z [INFO][AMF][Ngap][ran_addr:192.168.50.20:45354] SCTP_SHUTDOWN_EVENT notification, close the connection
2023-11-15T18:33:55.990097444Z [INFO][AMF][Ngap][ran_addr:192.168.50.20:45354] Remove RAN Context[ID: <PlmnID: {Mcc:001 Mnc:01}, GNbID: 0012345>]
2023-11-15T18:33:55.990501019Z [INFO][AMF][Ngap] Handle SCTP Notification[addr: ]
2023-11-15T18:33:55.990578005Z [WARN][AMF][Ngap] RAN context has been removed[addr: ]
2023-11-15T18:33:55.990887913Z [INFO][AMF][Ngap] Handle SCTP Connection Error[addr: ] - remove RAN
2023-11-15T18:33:55.991189761Z [WARN][AMF][Ngap] RAN context has been removed[addr: ]

and in Amarisoft Web GUI

PLMN was different for Free5gc but I modified the PLMN to 00101 which was provided by Amarisoft. In gnb PLMN is already pre-configured.

I’m confused regarding TAI, TAI is pre-defined as tac: 000001 # Tracking Area Code (3 bytes hex string, range: 000000~FFFFFF)

Leon777-coder · January 9, 2024, 3:40pm

Hello:
We reproduced the problem
Still, you need to change your PLMN ID in AMF, it seems like you only changed your RAN and UE’s PLMN. You need to change the AMF and SMF also.

Kumarsatyam1 · January 9, 2024, 3:40pm

Hi @Leon777-coder

You can check I put the PLMN which was given to me but I’m not able to find TAC ?

Now again I changed the tac:

so after changing tac I’m getting:

Leon777-coder · January 9, 2024, 3:40pm

Hello:

As the graph shows, you need to change the PLMN’s setting in the AMF, not the tac.

Kumarsatyam1 · January 9, 2024, 3:40pm

Hello,

I’ve already changed the PLMN. The TAC or TAI was provided in the Amarisoft web GUI in the NGAP connection.

Now, a new issue has arisen concerning authentication:

Where can I make modifications to resolve this error?

Kumarsatyam1 · January 9, 2024, 3:40pm

Hi Everyone does anybody know what is Autheitication Failure (MAC failure). And where can I modify?

and wireshark: 1) authentication request

authentication failure: 5GMM cause:

BR
Kumar Satyam

Kumarsatyam1 · January 9, 2024, 3:40pm

@free5GC don’t lock this.
It’s a humble request .

Leon777-coder · January 9, 2024, 3:40pm

Hello:
Based on the description on 3GPP TS 24.301 version 15.4.0 Release 15, section 5.4.2.6 :

MAC code failure:
If the UE finds the MAC code (supplied by the core network in the AUTN parameter) to be invalid, the UE shall send an AUTHENTICATION FAILURE message to the network, with the EMM cause #20 “MAC failure”. The UE shall then follow the procedure described in subclause 5.4.2.7, item c.

It can be seen from the protocol that the AUTN parameters sent by the core network are incorrect,the incorrect OP value causes the terminal to think that authentication has failed. Therefore I recommend you check whether your UE’s OPC and Webconsle’s OPC are the same or not.

Good Luck,
Leon

Kumarsatyam1 · January 9, 2024, 3:40pm

Hi,
on my free5gc webconsole:

and on my amari callbox classic on mme.cfg:

As well as I’m studying from 3GPP TS 34.108 version 15.0.0 Release 15 page 1023 i.e. 8.1.2.1 Authentication and key derivation in the test USIM and SS but I got confused.

BR
Kumar Satyam

Kumarsatyam1 · January 9, 2024, 3:40pm

Hi @Leon777-coder,

Currently, I’m getting error as:

[WARN][SMF][Main] Failed to setup an association with UPF[127.0.0.8], error:Request Transaction [7]: retry-out
2023-12-05T12:26:33.659516905Z [INFO][SMF][Main] Sending PFCP Association Request to UPF[127.0.0.8]

and [ERRO][UPF][Main] UPF Cli Run Error: open Gtp5g: open link: create: operation not supported

Do you have any idea regarding this.
BR
Kumar Satyam

Kumarsatyam1 · January 9, 2024, 3:40pm

Hi, @Leon777-coder and @howardswe499

In Amari Callbox Classic, I was performing a service LTE restart. By doing this, I can see logs in the Amarisoft WebGUI, where I can observe NGAP connection responses and requests."

In Free5GC, I run ./run.sh, and it shows me the following:

[INFO][AMF][Ngap] [AMF] SCTP Accept from: 192.168.50.20:35664
2023-12-12T15:55:44.851209074Z [INFO][AMF][Ngap] Create a new NG connection for: 192.168.50.20:35664
2023-12-12T15:55:44.853304479Z [INFO][AMF][Ngap][ran_addr:192.168.50.20:35664] Handle NGSetupRequest
2023-12-12T15:55:44.853398614Z [INFO][AMF][Ngap][ran_addr:192.168.50.20:35664] Send NG-Setup response

However, if I enable airplane mode, it shows me an authentication request, followed by failure and rejection in Wireshark. This time, I made some changes, such as in Amari Callbox Classic’s ue_db-ims.cfg, where I changed the AMF to 8000 instead of 0x90001 (Screenshot attached).

On the web console of Free5GC, I made a few changes like selecting Authentication Method EAP_AKA_PRIME instead of EAP_AKA (Screenshot attached). When I use EAP_AKA, Wireshark shows authentication request, failure, and rejection. However, when I select EAP_AKA_PRIME, Wireshark shows authentication request and response, along with UMTS authentication and key agreement (screenshot pcap attached).

Could you please provide insights on whether this is correct or incorrect?

BR
Kumar Satyam

free5GC · January 9, 2024, 3:40pm

Hi @Kumarsatyam1,
this question seems rather irrelavant to the previous questions and this topic, please create another topic for this question so the free5GC team can look into it further.
Thanks you.

Admin

Kumarsatyam1 · January 9, 2024, 3:40pm

Hi @free5GC

Which question is irrelevant? Why I have to create new topic we are discussing here.

BR
Kumar Satyam

howardswe499 · January 9, 2024, 3:40pm

Hi @Kumarsatyam1,
Regarding your problem about UPF failing to connect, I found this troubleshooting step from the official website; it seems relevant to your problem.
https://free5gc.org/guide/Trouble_Shooting/#7-smf-cannot-communicate-with-upf-upf-cannot-start-after-a-reboot-or-crash

Alternatively, if that does not work, I’ve found that restarting the 5GC sometimes works. (Remember to terminate all NFs by running ./force_kill.sh or find out the PID of the processes via sudo netstat -tulpn, then killing the processes one by one with sudo kill <pid>)

Best of luck,
Howard

Kumarsatyam1 · January 9, 2024, 3:40pm

Hi, @howardswe499,
This problem is solved now except the authentication request, failure, and response.

BR
Kumar Satyam

howardswe499 · January 9, 2024, 3:40pm

Hi @Kumarsatyam1,

Unfortunately I don’t have much experience with Free5GC integration with commercial 5G products, so the advice I can give is quite limited…

However, may I suggest running UERANSIM for the UE and gNB portion of your topology? It is lightweight and verified as working by the authors of Free5GC. It is also customizable, so you can try modifying the UE & subscriber info to be similar to your current setup and see if it still works. That way you can try to rule out problems in the config of your commercial device or Free5GC.

Best regards,
Howard