How to known if an user is connected to the 5GNSA from the core side?

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Hello guys,

How can I discover if an user is conected to the 5G NSA from the Core side? Is there any flag on HSS or any other element who show this? I’m considerating the 5GNSA trough the EPC.

I’m mean, in the 4G I can see the location information on the HSS, and the session information on the SGW. On the other hand, in the 5GSA I can see the same information on the UDM/SMF.

So, if the user is connected to the 5GNSA how can I see this information in the EPC?

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Check for dcnr flag.

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Nothing indicated from HSS side, as the HSS will reply with the NR as secondary RAT in the feature list & ARD (supported or not based on the provisioning )in the ULA during the normal 4G attach.

So, the HSS just provide the service or not to the MME and after that it didn’t know if the dial take the actual service or not, however for sure the EPC has more than indicator for the dial have the 5G NSA service or not (like DCNR flag).

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You should also set “max extended BW Uplink / Downlink” per user profile from HSS side.

All these HSS profile modifications just to grant 5G NSA service for the user, but not indicator if he got the service or not while roaming for example.

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Check on USN by display Session management on the Dial connected to high speed gateway flag: true.

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UE reports dcnr bit to MME.

This gives hint to MME UE is NR capable.

The real proof that UE actually connected to 5G of NSA comes from e-rab modification procedure. I am not 100 sure if HSS has any info on that.

In case of SA the the RAT type and NRCell id should give details if UE is present in 5G or 4G.

In fact, the HSS will send ‘NR as Secondary RAT Allowed/Not Allowed’ to MME in ULA/IDR.

So HSS has knowledge about UE’s NR capability.

The actual movement of the bearers to 5G happen when MME completes E-RAB modification procedure along with “Extended-XYZ” IEs to provide additional/5G bandwidth.