7 Trace record contents

12.083GPPSubscriber and equipment traceTS

7.1 General

Tables 9, 10 and 11 illustrate the structure of a trace record, and table 8 illustrates the structure of the Trace Record header. This header is used at the start of all trace records.

In the case where trace data is distributed over several records, linkage between the records is provided in the record header. If parallel events are also being traced, additional linkage for the traced data relating to each event is provided in the trace record content. Parallel events are not applicable to BSS trace records.

The trace reference, trace type and operation system identification are all provided on trace activation. Each record may contain an MSC, BSS or HLR event record. A key is included in the table indicating whether or not the field is mandatory. In this table and throughout the present document the key field has the following meaning:

M

This field must appear in at least one trace record associated with the invoking event. Any exceptions to this rule are explicitly described.

C

This field is only available under certain conditions. If available this field must be present in at least one trace record associated with the invoking event. The conditions under which this field is available are individually described.

O

This field is optional and its support is a matter for agreement between equipment manufacturer and network operator. Equipment manufacturers do not have to be capable of providing all these fields to claim conformance with the present document.

X

This field is not required in this instance.

Table 8: Trace Record Header

Field

Description

IMSI or IMEI

M

IMSI or IMEI of subscriber/equipment being traced. See GSM 12.05 annex B definitions for Served IMSI and Served IMEI. The BSS shall include this field in the reace record header only if available in the A-interface MSC INVOKE TRACE message.

Trace Reference

M

An identifier assigned by the OSF at Trace Activation which may be used by the OSF in conjunction with the IMSI/IMEI and the Transaction ID to uniquely identify a record or collection of records for one particular trace. This must always appear in every trace record.

Transaction id

C

An identifier of a particular transaction, described in GSM 08.08. It shall be included if available in the A‑Interface message MSC_INVOKE_TRACE.

Omc‑Id

O

The address of the OS entity that the OSF activating the trace requires priority trace records to be sent to by the NE performing the trace (see also clause 9 Trace Record Transfer).

MSC/BSS Trace Type

C

This field contains the MSC/BSS trace type as provided in the trace activation message (see clause 6.1 MSC/BSS Trace Type). It must always appear in the first record header.

HLR Trace Type

C

This field contains the HLR trace type as provided in the trace activation message (see clause 6.2 HLR Trace Type). It must always appear in the first record header.

MSC/BSS Trace Type Used

O

This field contains the MCS/BSS trace type which has been applied. This trace type may be different to the one provided in the trace activation message due to manufacturer constraints. It must always appear in the first record header.

HLR Trace Type Used

O

This field contains the HLR trace type which has been applied. This trace type may be different to the one provided in the trace activation message due to manufacturer constraints. It must always appear in the first record header.

Start Time

M

The time the compilation of the Trace Record was started. It must always appear in the first record header. All timestamps used in the TraceEvent Record are relative to this time.

End Time

M

The time the compilation of the Trace Record was completed. It must always appear in the last record header. It may be used by the OSF as an indication that the trace in that particular Network Element is completed.

Recording Entity

M

For MSC/HLR ‑ the E.164 number of the recording entity.

For BSS ‑ the BSC_ID as given in GSM 12.20 [11].

Alternatively the recording entity may be expressed as a graphic string.

Trace Event Record

M

This field contains either an MSC, HLR or BSS trace record as described in clauses 7.2 to 7.4 below. This must always appear in every trace record.

Sequence Number

C

This field is used to identify the sequence of records from a particular recording entity when more than one trace record is produced for the invoking event.

Reason For Record

C

This specifies why the record was generated by the NE (see clause 8.2). In addition to these reasons, other manufacturer specific reasons may be specified (see clause 8.2.3).

7.2 MSC Trace Record Content

The following types of fields are supported in the 2 MSC trace types.

Table 9: MSC Trace Record Content

Field

MSC Trace Type

Description

Basic

Detailed

Invoking Event

M

M

Event invoking trace (Not available at the non‑anchor MSC on Inter‑MSC Handover).

Served IMSI

C

C

IMSI of the calling party in the case of MOC or the called party in the event of MTC. Not available in case of emergency call without SIM. This field is only required for IMEI trace.

Served IMEI

C

C

IMEI of the calling ME in the case of MOC or the called party in the event of MTC. This field is only required for IMSI trace.

Served MSISDN

C

C

Primary MSISDN of the party being traced.

Calling/Called Number

C

C

The MSISDN of the calling party in case of MTC. The MSISDN of the called party in case of MOC.

Calling Subaddress

C

C

The subaddress of the calling party (for both MOC and MTC).

Called Subaddress

C

C

The subaddress of the called party (for both MOC and MTC).

Translated Number

C

C

The called number of the party not being traced after digit translation within the MSC (if applicable) (i.e. applies to MOC only).

Connected Number

C

C

The number of the party not being traced (applies to MOC only).

Forwarded‑to

Number

C

C

The number to which the call will be forwarded (applies to MTC only).

Forwarded‑to

Subaddress

C

C

The subaddress to which the call will be forwarded (applies to MTC only).

Redirecting Number

C

C

The number from which the call was last redirected (applies to MTC only).

Original Called

Number

C

C

The number of the original called party

(applies to MTC only).

Roaming Number

C

C

The MSRN of the traced subscriber in the case of MTC, or the MSRN of the called subscriber in case of MOC, if available.

Network Trunk

Group Point

C

C

In case of a MOC the outgoing trunk on which the call leaves the MSC. In case of an MTC the incoming trunk on which the call originates as seen from the MSC.

Basic Service

C

C

The bearer‑ or teleservice employed.

Radio Channel types

O

C

A list of radio channel types used during the compilation of the trace record, each timestamped.

BSS Handover Trunk

O

C

A list of the incoming/outgoing trunk group and member used to connect the MSC to BSS (including the original and each intra‑MSC BSS handover) each time‑stamped.

MSC Handover Trunk

O

C

A list of the trunk group and member used to connect two MSCs (including the original and each inter‑MSC handover) each time‑stamped.

Location

C

C

A list of Location Area Codes / Cell Ids used during the compilation of the trace record starting with the identity of the cell in which the invoking event originated or terminated, each time stamped.

SS Information

C

C

A list of information related to any SS actions carried out during the period of the trace.

The SS Information contains the SS Code for each SS Action, the Basic Services for which each SS action was carried out, the type of each SS action carried out, a list of SS parameters associated with each SS action, the result of each SS action and the Invoke Id allocated for each SS Action.

AOC Parameters

O

C

A list of the charge advice parameters sent to the MS (including on call set‑up and on changes as a result of a tariff switch over), each timestamped.

MS Classmark 2

C

C

A list of the mobile station classmark 2 information (starting with on call set‑up), each timestamped.

Call Termination Diagnostics

C

C

A detailed reason for the release of the connection. See GSM 12.05 annex B ‑ Diagnostics.

A‑Interface Messages

X

C

A sequential list of all DTAP and BSSMAP messages passed on the A‑Interface.

C‑Interface Messages

X

C

A sequential list of all MAP messages passed between the Tracing MSC and the HLR/AUC.

D‑Interface Messages

X

C

A sequential list of all MAP messages passed between the Tracing VLR and the HLR/AUC.

E‑Interface Messages

X

C

A sequential list of all MAP messages passed between the Tracing MSC and the subsequent MSC.

F‑Interface Messages

X

C

A sequential list of all MAP messages passed between the Tracing MSC and the EIR.

G‑Interface Messages

X

C

A sequential list of all MAP messages passed between the Tracing VLR and another VLR.

Network Signalling Messages

X

C

A sequential list of all user part messages e.g. ISUP, TUP messages.

Event Start Time

C

C

The time the event was started.

It must always appear in case the trace record is already being compiled and the event belonging to this event record for this same subscriber occurs.

Event Stop Time

C

C

The time the event was finished.

It must always appear in case the trace record is still being compiled due to an ongoing event and the event belonging to this event record finishes.

Event Number

M

M

The Event Number is used to identify tracing data belonging to the same event.

Record extensions

O

O

A set of network/ manufacturer specific extensions to the record.

7.3 BSS Trace Record Content

The following types of fields are supported in the 3 BSS trace record types:

Table 10: BSS Trace Record Content

Field

BSS Trace Type

Description

Basic

Handover

Radio

Invocation Message

M

M

M

GSM 08.08 [4] invocation message which started the trace action.

BTS ID

M

M

M

The ids of all BTSs accessed by the traced party during the period of the trace invocation (as per GSM 12.20 [11]), each timestamped.

TRX ID

M

M

M

The ids of all TRXs accessed by the traced party during the period of the trace invocation (as per GSM 12.20 [11]), each timestamped.

TRAU ID

O

O

O

The ids of all TRAUs accessed by the traced party during the period of the trace invocation (as per GSM 12.20 [11]), each timestamped.

Radio Channel Info.

M

M

M

The radio channel types and descriptions used during the period of the trace invocation, each timestamped.

Request type

C

C

C

The reasons for channel seizure (originating, terminating, re‑establishment, handover) (see GSM 04.08 [2]), each timestamped.

End Indication

C

C

C

The reasons for channel release (see GSM 04.08 [2]), each timestamped.

MS Power

X

C

C

The last MS power used before a channel is released (see GSM 12.20 [11]), each timestamped.

BS Power

X

C

C

The last BS power used before a channel is released (see GSM 12.20 [11]), each timestamped.

Timing advance

X

C

C

The last timing advance used before a channel is released (see GSM 12.20 [11]), each timestamped.

MS Classmark 1

C

C

C

The MS Classmark 1 indicated during the period of the trace invocation, each timestamped.

MS Classmark 2

C

C

C

The MS Classmark 2 indicated during the period of the trace invocation, each timestamped.

MS Classmark 3

C

C

C

The MS Classmark 3 indicated during the period of the trace invocation, each timestamped.

BSIC

M

M

M

This field is the combination of Network Colour Code and Base station Colour Code (see GSM 12.20 [11]).

CIC

C

C

C

The terrestrial circuit identification codes used for the call on which the trace is being performed, each timestamped (see GSM 08.08 [4]).

Handover result

O

C

C

The results of each handover occurring during the period of the trace invocation each timestamped.

Handover cause

O

C

C

The reasons for starting each handover attempt during the period of the trace invocation (see GSM 08.08 [4]), each timestamped.

Handover duration

O

C

C

The times taken between sending the handover command and receiving the handover complete for each successful handover, each timestamped.

Target Cell list

X

C

C

The target cells at the start of each handover attempt, each timestamped.

Synchronization information

X

C

C

The synchronization values for each handover attempt, each timestamped.

SCCP connection event

X

O

O

Each SCCP connection event used during the period of the trace invocation (Connection Request, Confirm, Refuse, Released, Released Complete), each timestamped.

BSSMAP message

X

C

C

L3 Message contents, during the period of the trace invocation, each timestamped, see GSM 08.08 [4].

DTAP message

X

O

O

L3 Message contents, during the period of the trace invocation each timestamped, see GSM 04.08 [2].

RR message

X

C

C

L3 Message contents, during the period of the trace invocation, each timestamped, see GSM 04.08 [2]. Only applies to those parts of the message between the BSC and the MS.

A‑bis Messages

X

X

C

All Abis messages except measurement reports and power control, each timestamped, see GSM 08.58 [5].

Timed A‑bis Messages

X

C

X

X Abis messages (except measurement reports and power control) received before and Y Abis messages received after a handover, each timestamped. X & Y are operator configurable parameters via MMI and are local to the BSS.

Measurement Reports

X

X

C

All uplink and downlink measurement reports, each timestamped, see GSM 08.58 [5].

Timed Measurement Reports

X

C

X

X uplink and downlink measurement reports received before and Y measurement reports received after a handover, each timestamped. X & Y are operator configurable parameters via MMI and are local to the BSS.

Power Control Messages

X

X

C

All power control messages, each timestamped, see GSM 08.58 [5].

Timed Power Control Message

X

C

X

X power control messages received before and Y power control messages received after a handover, each timestamped. X & Y are operator configurable parameters via MMI and are local to the BSS.

Record extensions

O

O

O

A set of network/ manufacturer specific extensions to the record.

7.4 HLR Trace Record Content

The following types of fields are supported in the 2 HLR trace record types:

Table 11: HLR Trace Record Content

Field

HLR Trace Type

Description

Basic

Detailed

Invoking Event

M

M

Event invoking trace.

Served MSISDN

C

C

Primary MSISDN of the party being traced.

MSC Address

C

C

Entity number of the serving MSC (GSM 12.05 [10] annex B).

VLR number

C

C

Entity number of the serving VLR (GSM 12.05 [10] annex B).

SS Information

C

C

A list of information related to any SS actions carried out during the period of the trace.

The SS Information contains the SS Code for each SS Action, the Basic Services for which each SS action was carried out, the type of each SS action carried out, a list of SS parameters associated with each SS action, the result of each SS action and the Invoke Id allocated for each SS Action.

Subscriber data

O

C

The subscriber data sent to the VLR after a location update.

Roaming number

C

C

The roaming number returned from the serving VLR.

SM Delivery outcome

C

C

The outcome of a MT SM delivery.

Alert reason

C

C

Indicates the reason why the SM service centre was alerted.

Service Centre address

C

C

The address of the SM service centre.

MAP interface messages

X

C

A sequential list of all MAP messages passed to and from the Tracing HLR.

Event Start Time

C

C

The time the event was started.

It must always appear in case the trace record is already being compiled and the event belonging to this event record for this same subscriber occurs.

Event Stop Time

C

C

The time the event was finished.

It must always appear in case the trace record is still being compiled due to an ongoing event and the event belonging to this event record finishes.

Event Number

M

M

The Event Number is used to identify tracing data belonging to the same event.

Record extensions

O

O

A set of network/ manufacturer specific extensions to the record.

7.5 Trace Record fields

Only those fields which are not defined in GSM 12.05 [10] annex B or are named differently from an identical field in GSM 12.05 [10] annex B are included here. Only supplementary information is included in this clause; where a description in tables 9 ‑ 11 is sufficient, no additional information is provided.

7.5.1 Radio channel information

When instructing the mobile to move to a new channel during procedures like Assignment, Immediate Assignment and Handover, the BTS must give the mobile all the necessary information such as frequency (frequencies if hopping), timeslot number, channel type etc. This is done using the Channel Description field defined in GSM 04.08 [2]. The structure of the Channel Description depends on whether or not frequency hopping is in use. These two cases are described below:

No Frequency Hopping

Channel Description (GSM 04.08 [2]), contains the following:

Channel Type (TCH, SDCCH etc.);

Timeslot Number (0 to 7);

TDMA Offset (0 to 7, used to identify SDCCH etc. within a timeslot);

Training sequence number;

Absolute Radio Carrier Frequency number.

Frequency Hopping

Channel Description (GSM 04.08 [2]), contains the following:

Channel Type (TCH, SDCCH etc.);

Timeslot Number (0 to 7);

TDMA Offset (0 to 7, used to identify SDCCH etc. within a timeslot);

Training sequence number;

Hopping Sequence Number;

Mobile Allocation Index Offset.

In this case, the channel description does not contain the list of frequencies to be used for hopping and an additional field indicating the mobile allocation is required. The mobile allocation is the set of frequencies to be used for hopping and is obtained from any of the following:

a) Cell Channel Description and Mobile Allocation;

b) Frequency Channel sequence;

c) Frequency List;

d) Frequency Short List.

In summary, to identify a GSM channel unambiguously the "Channel Description" field is sufficient on its own when frequency hopping is not used but mobile allocation is also required when hopping is in use.