Secondary RAT message usage report in ENDC

Hi all,

In ENDC, there is a process message called Secondary RAT Message Usage Report. Could someone please explain it in detail? Specifically:

  • Is it mandatory or optional?
  • Where does it appear in the call flow?

Thank you in advance.

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SRDUR (Secondary data usage report) is a optional procedure depends on gNB implementation.

This procedure will be enabled at NgB so that gNB should send the Data usage of an UE while release the UE.

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The master eNodeB has parameters that can enable this procedure.

As per 3GPP, it measures UE data at the PDCP layer.

If someone could share a detailed flow or diagram, it would make it easier to understand where and how this procedure fits in.

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Hi everyone, respect to this message I need to activate it between eNB–>MMe in Ericsson.
The parameter i have found for this is endcDataUsageReportEnabled under MOs:

-GNBCUUPFunction
-ENodeBFunction

Although I have set both in True I’m not seeing any report over S1.
I know Huawei and ZTE have special switches to allow this, someone can give me some light on this.
Thanks in advance.

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Hello, experts,

Could you confirm whether the “Secondary RAT messages” option is enabled in 5G-NSA?

If enabled, at which protocol level does it operate - S1-AP, GTP, or both?

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Yes, Secondary RAT messages are used, primarily within S1-AP and handled by S1-AP.

Their implementation largely depends on the operator’s configuration, considering factors like operator/vendor agreements and RAN sharing strategies.

However, GTP is not directly involved in handling these messages.

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How can I check if it is enabled on a live network?

I found something related to enabling secondary RAT data volume reporting from gNodeB to eNodeB on Huawei.

LST NRCELLNSADCCONFIG on gNodeB.

NR Data Volume Reporting Config (NRDATAVOLUMERPTCFG) is set to 0 by default.

You need to modify it using MOD NRCELLNSADCCONFIG, typically setting it to 60.

This parameter determines whether periodic and event-based NR traffic reporting is enabled:

  • 0 → The gNodeB does not report NR traffic to the eNodeB.
  • 65535 → The gNodeB reports NR traffic only based on events.
  • 60 - 36000 → The gNodeB reports NR traffic based on events and periodically, with the value representing the reporting interval.

This parameter applies only to FDD and TDD.

Modify NSADCMGMTCONFIG for each LTE LocalCellID and set the NRDATAVOLUMERPTCFG value according to your requirement (recommended: 60).

Modify NRCELLNSADCCONFIG for each NR CellID and set the NRDATAVOLUMERPTCFG value according to your requirement (recommended: 60).

Verify both commands.

These commands are for the RAN side.

We use them to resolve these cases in our network.

You can also coordinate with the Core Team, as a field will be available in the CDR:

ListofRAN-Secondary-RAT-Usage-Report.

Hi Sami

What i have observed from RAN perspective it is sent by X2 (eNB<->gNB), then through S1 AP (BBU ↔ MMe) and i suppose then via GTP to P-GW.
Respect to my question i have got a celltrace and confirm S1 is being used so now core team is analyzing how EPS is processing it.

Attach is the result of celltrace converted to CSV file.
secondary_data_report.txt (167.6 KB)

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