4.2.2 Starting a trace recording session – management based

32.4223GPPRelease 17Subscriber and equipment traceTelecommunication managementTrace control and configuration managementTS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

4.2.2.1 UTRAN starting mechanisms

In an RNC, a Trace Recording Session should start after the reception of the CN_INVOKE_TRACE message from the CN and if some activities have been started on the interfaces that have been requested to be traced. The RNC shall record those signalling messages in the interfaces that are defined in the list of interfaces parameter. Trace depth defines whether entire signalling messages or just some IEs needs to be recorded.

The RNC may not start a Trace Recording Session if there are insufficient resources available for the recording.

When RNC starts a Trace Recording Session it shall assign a Trace Recording Session Reference for the Trace Recording Session.

When several PLMNs are supported in the RAN, for starting Trace and management based MDT the RNC shall only select UEs where the pLMNTarget = PLMN identity that the UE includes in Initial Direct Transfer message 3GPP TS 25.331 [31].

4.2.2.2 PS Domain starting mechanisms

In a SGSN/GGSN/BM-SC, a Trace Recording Session should start after the reception of a Trace Session Activation from EM and if any of the defined start triggering events occur. During the Trace Recording Session, the SGSN/GGSN/BM-SC shall record those signalling messages in the interfaces that are defined in the list of interfaces parameter. The Trace Depth parameter defines whether entire signalling messages or just some IEs need to be recorded.

The IMSI and IMEISV shall be available in the SGSN, in the GGSN and in the BM-SC for at least those connections which shall be traced.

The SGSN/GGSN/BM-SC may not start a Trace Recording Session if there are insufficient resources available for the recording.

If the SGSN/GGSN/BM-SC receives the Trace Session Activation during an established session (e.g. during an active PDP context or an active MBMS context), it may start the Trace Recording Session immediately. However, if any of the start triggering events occur in the SGSN/GGSN/BM-SC after receiving the Trace Session Activation, it shall start the Trace Recording Session.

When a Trace Recording Session is started, the SGSN/GGSN/BM-SC shall assign a Trace Recording Session Reference for the Trace Recording Session.

4.2.2.3 CS Domain starting mechanisms

In a MSC Server, a Trace Recording Session shall start after the reception of a Trace Session Activation from EM and if any of the defined start triggering events occur. During the Trace Recording Session, the MSC Server shall record those signalling messages in the interfaces that are defined in the list of interfaces parameter. The Trace Depth parameter defines whether entire signalling messages or just some IEs needs to be recorded.

The IMSI and the IMEISV shall be available in the MSC Server for at least those connections which shall be traced.

The MSC Server may not start a Trace Recording Session if there are insufficient resources available for the recording.

If the MSC Server receives the Trace Session Activation during an established call, it may start the Trace Recording Session immediately. However, if any of the start triggering events occurs in MSC Server after receiving the Trace Session Activation, it shall start the Trace Recording Session.

When a Trace Recording Session is started, the MSC Server shall assign a Trace Recording Session Reference for the Trace Recording Session.

4.2.2.4 Void

4.2.2.5 E-UTRAN starting mechanism

In E-UTRAN, after the Cell Traffic Trace has been activated in the monitored cell(s), the eNodeB shall start a Trace Recording Session for new call(s)/session(s) and for already existing call(s)/session(s) (events for existing call(s)/session(s) are not required to be recorded prior to the activation of the cell traffic trace). When the eNodeB starts a Trace Recording Session it shall allocate a Trace Recording Session Reference for the given call or session. The eNodeB shall send the allocated Trace Recording Session Reference, and the Trace Reference and the Trace Collection Entity IP Address in the CELL TRAFFIC TRACE message to the MME via the S1 connection.

When MME receives this new S1 signalling message containing the Trace Recording Session Reference and Trace Reference, the MME shall look up the IMSI/IMEI(SV) of the given call from its database and shall send the IMSI/IMEI(SV) numbers together with the Trace Recording Session Reference and Trace Reference to the Trace Collection Entity.

When several PLMNs are supported in the RAN, for starting Trace the eNB shall only select UEs where the pLMNTarget = selectedPLMN-Identity that the UE includes in RRCConnectionSetup message 3GPP TS 36.331 [32].

The format of the file sent to the TCE from the MME is defined in 3GPP TS 32.423 [3], clause A.2.2.

The figure 4.2.2.5.1 illustrates the procedure.

Figure 4.2.2.5.1

4.2.2.6 EPC Domain starting mechanisms

In a MME, SGW or PGW, a Trace Recording Session should start after the reception of a Trace Session Activation from EM and if any of the defined start triggering events occur. During the Trace Recording Session, the MME, SGW or PGW shall record those signalling messages in the interfaces that are defined in the list of interfaces parameter. The Trace Depth parameter defines whether entire signalling messages or just some IEs need to be recorded.

The IMSI and IMEISV shall be available in the MME and in the SGW for at least those connections which shall be traced.

The MME, SGW or PGW may not start a Trace Recording Session if there are insufficient resources available for the recording.

If the MME, SGW or PGW receives the Trace Session Activation during an established session (e.g. during an active PDP context), it may start the Trace Recording Session immediately. However, if any of the start triggering events occur in the MME, SGW or PGW after receiving the Trace Session Activation, it shall start the Trace Recording Session.

When a Trace Recording Session is started, the MME, SGW or PGW shall assign a Trace Recording Session Reference for the Trace Recording Session.

4.2.2.7 E-UTRAN starting mechanisms for MDT

A trace recording session of immediate MDT or logged MDT or Logged MBSFN MDTshall be started in the eNodeB for each selected UE that satisfy the MDT UE selection criteria (i.e. capability condition), provided that a cell trace session for immediate MDT or logged MDT or Logged MBSFN MDT has been activated in the eNodeB from EM for the given cell(s) before.

The eNodeB shall configure the corresponding MDT RRC measurements at the selected UE.

When several PLMNs are supported in the RAN for management based MDT, possibly combined with Trace, the eNB shall only select UEs where the pLMNTarget = selectedPLMN-Identity that the UE includes in RRCConnectionSetup message 3GPP TS 36.331 [32].

4.2.2.8 Starting mechanisms at UE for MDT

There is no starting mechanism at the UE for MDT trace recording sessions. The UE shall execute the received MDT measurement configuration. In case of logged MDT or Logged MBSFN MDT, the UE shall store the trace recording session parameters as received from the eNodeB.

When several PLMNs are supported in the RAN, for starting logged MDT the UE shall only perform logging for the cells recived in the MDT measuerment configuration, if they are allowed as selected PLMNs.

When several PLMNs are supported in the RAN, for starting Logged MBSFN MDT the UE shall only perform logging for the cells and MBSFN area received in the MDT measurement configuration, if they are allowed as selected PLMNs.

4.2.2.9 5GC Domain starting mechanisms

In an AF, AMF, AUSF, NEF, NRF, NSSF, PCF, SMF, SMSF, UPF or UDM, a Trace Recording Session should start after the reception of a Trace Session Activation from management system and if any of the defined start triggering events occur. During the Trace Recording Session, the AF, AMF, AUSF, NEF, NRF, NSSF, PCF, SMF, SMSF, UPF or UDM shall record those signalling messages in the interfaces that are defined in the list of interfaces parameter. The Trace Depth parameter defines whether entire signalling messages or just some IEs need to be recorded.

The SUPI and IMEISV shall be available in the AMF, SMF and in the PCF for at least those connections which shall be traced.

The AF, AMF, AUSF, NEF, NRF, NSSF, PCF, SMF, SMSF, UPF or UDM may not start a Trace Recording Session if there are insufficient resources available for the recording.

If the AF, AMF, AUSF, NEF, NRF, NSSF, PCF, SMF, SMSF, UPF or UDM receives the Trace Session Activation during an established session, it may start the Trace Recording Session immediately. However, if any of the start triggering events occur in the AF, AMF, AUSF, NEF, NRF, NSSF, PCF, SMF, SMSF, UPF or UDM after receiving the Trace Session Activation, it shall start the Trace Recording Session.

When a Trace Recording Session is started, the AF, AMF, AUSF, NEF, NRF, NSSF, PCF, SMF, SMSF, UPF or UDM shall assign a Trace Recording Session Reference for the Trace Recording Session.

4.2.2.10 NG-RAN starting mechanism

In NG-RAN, after the Cell Traffic Trace has been activated in the monitored cell(s), the NG-RAN node shall start a Trace Recording Session for new call(s)/session(s) and for already existing call(s)/session(s) (events for existing call(s)/session(s) are not required to be recorded prior to the activation of the cell traffic trace). When the NG-RAN node starts a Trace Recording Session it shall allocate a Trace Recording Session Reference (TRSR) for the given call or session. For file-based trace reporting, the NG-RAN node shall send the allocated Trace Recording Session Reference, the Trace Reference and the Trace Collection Entity IP Address in the CELL TRAFFIC TRACE message to the AMF via the NG connection. For streaming trace reporting, the NG-RAN node shall send the allocated Trace Recording Session Reference, the Trace Reference and the URI of the Trace Reporting MnS consumer in the CELL TRAFFIC TRACE message to the AMF via the NG connection.

When AMF receives this new NG signalling message containing the Trace Recording Session Reference (TRSR) and Trace Reference (TR), the AMF shall look up the SUPI/IMEI(SV) of the given call from its database and shall send the SUPI/IMEI(SV) numbers together with the Trace Recording Session Reference and Trace Reference to the Trace Collection Entity in case of the file-based trace reporting, or to Trace Reporting MnS consumer in case of the streaming trace reporting.

When several PLMNs are supported in the RAN, for starting Trace the NG-RAN node shall only select UEs where the pLMNTarget = selectedPLMN-Identity that the UE includes in RRCConnectionSetup message 3GPP TS 38.331 [43].

For file-based trace reporting, the format of the file sent to the TCE from the AMF is defined in 3GPP TS 32.423, clause A.2.2.

For streaming trace reporting, the format of the AMF data sent to Trace Reporting MnS consumer is defined in 3GPP TS 32.423 [3].

The figure 4.2.2.10.1 illustrates the procedure for file-based trace reporting.

Figure 4.2.2.10.1: NG-RAN trace starting mechanism with file-based trace reporting

The figure 4.2.2.10.2 illustrates the procedure for streaming trace reporting.

Figure 4.2.2.10.2: NG-RAN trace starting mechanism with streaming trace reporting

4.2.2.11 NG-RAN starting mechanisms for management based MDT

A trace recording session of immediate MDT or logged MDT shall be started in the gNB for each selected UE that satisfy the MDT UE selection criteria (i.e. capability condition), provided that a cell trace session for immediate MDT or logged MDT has been activated in the gNB from management system for the given cell(s) before.

The gNB shall configure the corresponding MDT RRC measurements at the selected UE.

When several PLMNs are supported in the RAN for management based MDT, possibly combined with Trace, the gNB shall only select UEs where the pLMNTarget = selectedPLMN-Identity that the UE includes in RRCConnectionSetup message 3GPP TS 38.331 [43].