8.17 CN Invoke Trace

25.4133GPPRelease 17TSUTRAN Iu interface Radio Access Network Application Part (RANAP) signalling

8.17.1 General

When used for signalling based activation, the purpose of the CN Invoke Trace procedure is to inform the RNC that it should begin a trace session with the parameters indicated by the CN and related to the UE, the Iu connection is used for.

When used for management based activation, the purpose of the CN Invoke Trace procedure is to provide the RNC with the equipment identity of the UE for which the RNC should begin a trace recording session.

The procedure uses connection oriented signalling.

8.17.2 Successful Operation

Figure 18: CN Invoke Trace procedure. Successful operation.

The CN Invoke Trace procedure is invoked by the CN by sending a CN INVOKE TRACE message to the RNC as defined in TS 32.422 [38].

The CN INVOKE TRACE message shall include the following IEs:

– The Trace Reference IE, which uniquely identifies the trace session it refers to.

– The UE Identity IE, which indicates the UE to which this trace session pertains.

– The Trace Propagation Parameters IE, only in case of a signalling based activation.

If present, the Trace Propagation Parameters IE shall include the following IEs:

– The Trace Recording Session Reference IE, which is allocated by the CN.

– The Trace Depth IE, which defines how detailed information should be recorded for this trace session in the RNC.

The Trace Propagation Parameters IE may also include the List Of Interfaces To Trace IE, which defines which interfaces should be traced in the RNC. If the List Of Interfaces To Trace IE is not included, the RNC should trace all the following interfaces, if available: Iu-CS, Iu-PS, Uu, Iur and Iub.

Upon receiving the CN INVOKE TRACE message, which includes the Trace Propagation Parameters IE, the RNC should begin a trace recording session according to the parameters indicated in the CN INVOKE TRACE message. If the RNC does not support the requested value "Minimum" or "Medium" of the Trace Depth IE, the RNC should begin a trace recording session with maximum trace depth.

Upon receiving the CN INVOKE TRACE message, which does not include the Trace Propagation Parameters IE, the RNC should begin a trace recording session according to the parameters configured in the RNC for the indicated equipment identity in the CN INVOKE TRACE message.

The RNC may not start a trace recording session if there are insufficient resources available within the RNC.

The Trace Reference IE, UE identity IE and, if the Trace Propagation Parameters IE is present, the Trace Recording Session Reference IE are used to tag the trace record to allow simpler construction of the total record by the entity which combines trace records.

If the MDT Configuration IE is included in the CN INVOKE TRACE message and includes the MDT Activation IE set to “Immediate MDT and Trace” then the RNC shall, if supported, initiate the requested trace function and MDT function as described in TS 32.422 [38].

If the MDT Configuration IE is included in the CN INVOKE TRACE message and includes the MDT Activation IE set to “Immediate MDT Only” or “Logged MDT only”, then the RNC shall, if supported, initiate the requested MDT function as described in TS 32.422 [38] and shall ignore the List of Interfaces to Trace IE and the Trace Depth IE.

If Trace Collection Entity IP Address IE is included and if the MDT Configuration IE is also included then the RNC shall, if supported, store the Trace Collection Entity IP address and use it when transferring Trace records, otherwise if MDT Configuration IE is not included, the RNC may use the Trace Collection Entity IP address when transferring trace records.

If the MDT Configuration IE is included in the CN INVOKE TRACE message and includes the Signalling based MDT PLMN List IE, then the RNC may used it to propagate the trace function as described in TS 37.320 [64].

If the UE Application Layer measurement configuration IE is included in the CN INVOKE TRACE message then the RNC shall, if supported, initiate the requested trace function and QoE function as described in TS 25.300 [72].

Interaction with Relocation and Enhanced Relocation:

In case of signalling based activation, the order to perform tracing is lost in UTRAN at successful Relocation of SRNS. If the tracing shall continue also after the relocation has been performed, the CN Invoke Trace procedure shall thus be re-initiated from the CN towards the future SRNC after the Relocation Resource Allocation or the Enhanced Relocation procedure has been executed successfully.

8.17.2.1 Successful Operation for GERAN Iu mode

The CN INVOKE TRACE message shall include the Trace Type IE to indicate the events and parameters to be recorded.

The message shall include a Trace Reference IE which is allocated by the entity which triggered the trace.

The message may include the OMC ID IE, which if present, indicates the OMC to which the record is destined.

The message may include the UE Identity IE, which if present, indicates the UE to which this record pertains to.

The message may include the Trigger ID IE, which if present, indicates the entity which triggered the trace.

The Trace Reference and Trigger ID IEs are used to tag the trace record to allow simpler construction of the total record by the entity which combines trace records.

8.17.3 Abnormal Conditions

If the MDT Configuration IE is included in the CN INVOKE TRACE message and the Trace Collection Entity IP Address IE is not included, the RNC shall ignore the MDT Configuration.

If the QoE Configuration IE is included in the CN INVOKE TRACE message and the Trace Collection Entity IP Address IE is not included, the RNC shall ignore the QoE Configuration.

8.17.3.1 Abnormal Conditions for GERAN Iu mode

Not applicable.