4.2.5 Stopping a trace recording session – signalling based

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

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

4.2.5.1 UTRAN stopping mechanisms

In an RNC the Trace Recording Session will always be the same as the Trace Session as no triggering events are defined in UTRAN. Therefore a Trace Recording Session shall always be stopped in an RNC when the RNC deactivates the Trace Session. For more information on Trace Session deactivation in UTRAN see subclause 4.1.4.2.

4.2.5.2 PS Domain stopping mechanisms

A Trace Recording Session shall be stopped when the SGSN/GGSN/BM-SC detect any of the stop triggering events.

However, if a SGSN receives a Trace Session deactivation either from its EM (in case of tracing roaming subscribers) or from HSS (in case of tracing home subscribers) during an ongoing Trace Recording Session, it may stop it immediately or at any time until the occurrence of an appropriate stop-triggering event.

A GGSN shall stop a Trace Recording Session when it receives a Trace Session deactivation message (GTP- Update PDP Context Request and Trace Activity Control is set to Trace Deactivation )from the SGSN or at any time until the occurrence of an appropriate stop-triggering event.

A BM-SC shall stop a Trace Recording Session when it receives a Diameter Gmb STR message from the GGSN or at any time until the occurrence of an appropriate stop-triggering event.

When a Trace Recording Session is stopped in a SGSN, the SGSN shall send a Trace Session deactivation message to the NEs where tracing was required, as defined in the "List of NE types" configuration parameter, received in the Trace Session activation message. The Trace Reference, used for the deactivation procedure, shall be the same as used in the SGSN for the activation of the Trace Session.

The following figure illustrates a successful case in tracing a PDP context, when a Trace Recording Session is stopped. (Reference 3GPP TS 23.060 [6].)

NOTE: The activation to SGSN can come from EM-SGSN (in the figure just EM) or from the HSS.

Figure 4.2.5.2.1: Stopping a Trace Recording Session for a PDP Context (Signalling based) – PS domain

The following figure illustrates a successful case in tracing a MBMS context, when a Trace Recording Session is stopped. (Reference 3GPP TS 23.246 [9].)

Figure 4.2.5.2.2: Stopping a Trace Recording Session for a MBMS Context (Signalling based) – PS domain

4.2.5.3 CS Domain stopping mechanisms

A Trace Recording Session shall be stopped when the MSC Server and MGW detect any of the stop triggering events.

However, if a MSC Server receives a Trace Session deactivation either from its EM (in case of tracing roaming subscribers) or from HSS (in case of tracing home subscribers) during an ongoing Trace Recording Session, it may stop it immediately or at any time until the occurrence of an appropriate stop-triggering event.

A MGW shall stop a Trace Recording Session when it receives a MOD command with trace package (indicating Trace Deactivation) from the MSC Server or at any time until the occurrence of an appropriate stop-triggering event.

When a Trace Recording Session is stopped in a MSC Server, the MSC Server shall send a Trace Session deactivation message to the NEs where tracing was required, as defined in the "List of NE types" configuration parameter, received in the Trace Session activation message. The Trace Reference, used for the deactivation procedure, shall be the same as used in the MSC Server for the activation of the Trace Session.

The following figure illustrates a successful case in tracing a call, when a Trace Recording Session is stopped. (Reference 3GPP TS 23.205 [7] and 3GPP TS 23.108 [8].)

Figure 4.2.5.3.1: Stopping a Trace Recording Session (Signalling based) – CS domain

4.2.5.4 Void

4.2.5.5 Service level tracing for IMS stopping mechanism

4.2.5.5.1 General

The following figure illustrates the stopping of a trace recording session at the UE, P-CSCF, S-CSCF, I-CSCF and HSS (Steps 13 to 22) following the unsuccessful attempt of an IP multimedia subsystem procedure. For clarity purposes the starting of trace recording sessions are also illustrated (steps 1 to 12). In the case where the HSS is unable to fulfil a Diameter User location query from the I-CSCF (see 3GPP TS 29.228 [16]), the HSS shall return to the I-CSCF a permanent failure in the Diameter location query response (Steps 13 and 15). At this point the HSS and the I-CSCF shall stop their trace recording sessions (Steps 14 and 16). On reception of the SIP Final Response containing the permanent failure status code the S-CSCF, P-CSCF and UE stop their trace recording sessions (Steps 17 to 22).

Figure 4.2.5.5.1.1: Stopping a Trace Recording Session following the unsuccessful attempt of an IP multimedia subsystem procedure

4.2.5.5.2 Stopping mechanism at the UE

A UE (both originating and terminating) shall stop a trace recording session immediately following:

1) The termination of an IP multimedia subsystem procedure (as defined in 3GPP TS 23.228 [15]). For example, when a successfully established IP multimedia subsystem session ends, or upon a SIP Final Response message (2xx, 3xx, 4xx, 5xx and 6xx response codes).

2) The detection of a stop-triggering event (e.g. time expiry period) as defined by the trace control and configuration parameters within the received management operation.

3) The detection of a stop-triggering event originating directly from the Device Management server for a specific Trace Recording Session(s).

Depending on Operator conditions, when a UE receives from the Device Management server a request to deactivate the management operation it shall either:

1) Continue the Trace Recording Session (s) until it ends gracefully; or

2) Stop the Trace Recording session (s) immediately.

In all cases, the UE shall deactivate the Trace Session (s) immediately at the end of the Trace Recording Session(s).

When a UE receives a request to deactivate the management operation no new Trace Recording sessions shall be initiated.

4.2.5.5.3 Stopping mechanism at the IMS NE

An IMS NE (i.e. S/I/P-CSCF, AS, HSS, MRF, MGCF, BGCF) shall stop a trace recording session immediately following:

1) The termination of an IP multimedia subsystem procedure (as defined in 3GPP TS 23.228 [15]). For example, when a successfully established IP multimedia subsystem session ends.

2) The detection of a stop-triggering event (e.g. time expiry period) as defined in the Trace Session Activation message.

When an IMS NE receives a Trace Session deactivation during an ongoing Trace Recording Session, it may stop the Trace Recording Session immediately or at any time until the occurrence of an appropriate stop-triggering event.

4.2.5.6 Service level tracing Trace session deletion and trace retrieval

As described in clause 4.1.4.6.3, Trace Session deactivation shall be initiated from the Device Management Server. Following the completion of any trace recording sessions at the UE and during the subsequent deactivation of the Trace Session, the UE shall indicate to the Device Management server that Trace Records are available for retrieval.

Once the Trace records have been retrieved the management object may be deleted from the UE.

4.2.5.7 E-UTRAN stopping mechanisms

In an eNB the Trace Recording Session will always be the same as the Trace Session as no triggering events are defined in E-UTRAN. Therefore a Trace Recording Session shall always be stopped in an eNB when the eNB deactivates the Trace Session since there can be only one trace reference/trace recoding session reference combination per Trace Session at any given time. For more information on Trace Session deactivation in E-UTRAN, see clause 4.1.4.8.

4.2.5.8 EPC Domain stopping mechanisms

A Trace Recording Session may be stopped when the MME/SGW/PGW detect any of the stop triggering events. Detection of a stop trigger event results in MME/SGW/PGW immediately stopping the trace recording session.

However, if an MME receives a Trace Session deactivation either from its EM (in case of tracing roaming subscribers) or from HSS (in case of tracing home subscribers) during an ongoing Trace Recording Session, it may stop it immediately or at any time until the occurrence of an appropriate stop-triggering event.

When a Trace Recording Session is stopped in an MME, the MME may send a S1-Deactivate Trace message to the eNB where tracing was required, as defined in the "List of NE types" configuration parameter, received in the Trace Session activation message. . If the triggering event parameter indicates that all events shall be traced, the MME shall not send the S1-Deactivate Trace message to the eNB. If the Trace Recording Session is not terminated in the MME, then it shall not be deactivated in the eNB. The Trace Reference, used for the deactivation procedure, shall be the same as used in the MME for the activation of the Trace Session. This only applies to the eNB as the PGW and SGW have their own triggering criteria.

4.2.5.9 EPC stopping mechanisms for MDT

There is no stopping mechanism in the EPC for MDT trace recording sessions, as there are no starting mechanisms either (see also clause 4.2.3.8).

4.2.5.10 E-UTRAN stopping mechanisms for MDT

In case of immediate MDT, the eNodeB shall stop an ongoing trace recording session for a given UE when a trace session deactivation is received from the MME. The eNodeB shall deactivate the corresponding MDT measurements in the UE.

If the configured area scope is not satifisfied in the target cell after a handover, the eNB may deactivate the Immediate MDT configured to the UE like explained in clause 4. 4.

In case of logged MDT or Logged MBSFN MDT, there is no stopping mechanism in the eNodeB. The eNodeB does not need to maintain a logged MDT or Logged MBSFN MDT trace recording session once it has been configured in the UE.

4.2.5.11 Stopping mechanisms at UE for MDT

In case of logged MDT or Logged MBSFN MDT, the UE shall stop an ongoing trace recording session when logging duration expires and it shall indicate the availability of logged measurement results to the network next time it enters connected mode.

The UE shall discard an ongoing logged MDT trace recording session when it receives a new logged MDT or Logged MBSFN MDT trace recording session configuration from the network.

The UE shall discard an ongoing logged MBSFN MDT trace recording session when it receives a new logged MDT or logged MBSFN MDT trace recording session configuration from the network.

4.2.5.12 5GC Domain stopping mechanisms

A Trace Recording Session may be stopped when the AMF, PCF, SMF or UPF detect any of the stop triggering events. Detection of a stop trigger event results in AMF, PCF, SMF or UPF immediately stopping the trace recording session.

However, if an AMF receives a Trace Session deactivation either from its management system (in case of tracing roaming subscribers) or from UDM (in case of tracing home subscribers) during an ongoing Trace Recording Session, it may stop it immediately or at any time until the occurrence of an appropriate stop-triggering event.

When a Trace Recording Session is stopped in an AMF, the AMF may send a NG-Deactivate Trace message to the NG-RAN node where tracing was required, as defined in the "List of NE types" configuration parameter, received in the Trace Session activation message. . If the triggering event parameter indicates that all events shall be traced, the AMF shall not send the NG-Deactivate Trace message to the NG-RAN node. If the Trace Recording Session is not terminated in the AMF, then it shall not be deactivated in the NG-RAN node. The Trace Reference, used for the deactivation procedure, shall be the same as used in the AMF for the activation of the Trace Session. This only applies to the NG-RAN node as the 5GC nodes have their own triggering criteria.

4.2.5.13 NG-RAN stopping mechanisms

In a NG-RAN node the Trace Recording Session will always be the same as the Trace Session as no triggering events are defined in NG-RAN. Therefore a Trace Recording Session shall always be stopped in an NG-RAN node when the NG-RAN node deactivates the Trace Session since there can be only one trace reference/trace recoding session reference combination per Trace Session at any given time. For more information on Trace Session deactivation in NG-RAN, see subclause 4.1.4.12.

4.2.5.14 5GC stopping mechanisms for signalling based MDT

There is no stopping mechanism in the 5GC for MDT trace recording sessions, see clause 4.2.3.13.

4.2.5.15 NG-RAN stopping mechanisms for signalling based MDT

In case of immediate MDT, the gNB shall stop an ongoing trace recording session for a given UE when a trace session deactivation is received from the AMF. The gNB shall deactivate the corresponding MDT measurements in the UE.

If the configured area scope is not satisfied in the target cell after a handover, the gNB may deactivate the Immediate MDT configured to the UE like explained in clause 4.4.

In case of logged MDT, there is no stopping mechanism in the gNB. The gNB does not need to maintain a logged MDT trace recording session once it has been configured in the UE.