Relate UE_ID with Core Identifier

Q/A
#1

Hi,

I have a question about the following procedure:
We currently have the Free5GC Core running in Docker containers, connected to an OAI-developed gNB and nrUE. We’re also developing an API that will consume core metric data (collected by a custom xAPP) to analyze this data and return information about the quality of service experienced by a specific user device.

The issue is that the xAPP only provides the UE_ID, which is defined by the RAN, while in the API we only have the IP address. Therefore, I’d like to know if there’s a way to correlate the UE_ID with some piece of information that identifies the UE in the Core (such as IP, IMSI + gNB ID, etc.).

So far, the only idea we’ve come up with is to monitor the container logs and extract the UE_ID and SUPI from the messages.

Thank you in advance to anyone who can provide some guidance on this!

Best regards,
Higor.

#2

Hi,

Based on our experiments, free5GC’s current SBI/OAM does not provide a function to directly map a RAN UE_ID (e.g., RanUeNgapId) to a SUPI or a UE IP address. Using NRF-issued access tokens to call the AMF OAM lets you retrieve registered-ue-context for all registered UEs (e.g., SUPI and SmContextRef) but not the UE_ID; you can then use the SmContextRef together with the SMF OAM to obtain the UE IP (PDUAddress).

To achieve a direct RanUeNgapId→SUPI mapping, you must employ approaches such as inspecting the AMF’s runtime memory, capturing NGAP/E2 packets for correlation, or adding a feedback mechanism on the RAN/AMF side (which requires code changes).