24 Procedures for trunk originated services

22.0783GPPCustomised Applications for Mobile network Enhanced Logic (CAMEL)Release 17Service descriptionStage 1TS

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

Trunk originated services may be provided by a PLMN operator.

When overlap signaling procedures are used a TO call setup request may only contain a partial digit string. The PLMN may:

– wait to collect all digits before following the procedures below (Note: this may result in a delay in call set-up); or

– collect a minimum number of digits before following the procedures below (Note: it may be necessary to avoid the use of CSE-initiated user interaction while additional digits are still being received); or

– support CSE requests for additional digit collection, as defined below (Note: it may be necessary to avoid the use of CSE-initiated user interaction while additional digits are collected)

24.1 Initial service events

It shall be possible to specify which of the following initial service events shall initiate contact with the CSE:

– Collection of dialled digits;

– Analysis of dialled digits.

The definition of which of the above initial service events shall initiate contact with the CSE is part of the Trunk Originated CAMEL Service Information and Network CAMEL Service Information, respectively, provisioned by the PLMN operator. The provisioning mechanism is out of the scope of this specification.

Analysis of dialled digits can open a new dialogue regardless of whether a relationship exists.

24.2 Criteria for contact with the CSE

It shall be possible for the PLMN to specify criteria which must be satisfied before the CSE is contacted.

24.2.1 Criteria applicable at call setup

24.2.1.1 Criteria applicable at call setup when dialled digits have been collected

Criteria may be defined for the case when collection of dialled digits has been performed. Criteria may be based on the contents and/or length of the dialled number, basic service, call type or other information at the discretion of the network operator, however this is outside the scope of this specification.

24.2.1.2 Criterion applicable at call setup when dialled digits are analysed

Criteria on the contents of the called number may be defined for dialled services at the discretion of the network operator, however this is outside the scope of this specification.

24.3 Call set-up request procedure

24.3.1 Procedure when dialled digits have been collected

The purpose of this procedure is to detect a call set-up request at the point where digits have been collected but not analysed, and to allow the CSE to modify the handling of the call set-up request.

If no control relationship for the call exists and:

– The incoming trunk is provisioned with a Trunk originated CAMEL service; and

– The call set-up request occurs; and

– The criteria are satisfied.

Then the PLMN shall suspend call processing, make contact with the CSE and await further instructions.

When the PLMN has made contact with the CSE, and the CSE has determined that additional digits are required in order to determine the appropriate handling for the call, the CSE shall instruct the PLMN to act as described below.

– Activate subsequent control service event for the call. The CSE shall request that the following subsequent service event shall be detected and reported:

– Collection of dialled digits. The CSE may specify the number of digits to be collected

– The type of monitoring (control or notification)

Once the CSE has concluded issuing the above instruction, it shall issue the following instruction:

– Collect information (i.e. CSE request for the collection of additional digits).

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Otherwise, when the PLMN has made contact with the CSE, the CSE shall be able to instruct the PLMN to act as described below.

– Perform charging activities;

– Activate subsequent control service events for the call. The CSE shall have the possibility to send the following information:

– The subsequent service event which shall be detected and reported:

– Called party alert;

– Called party connection;

– Call disconnection;

– Calling party abandon;

– Unsuccessful call establishment. In the case of no answer the CSE may provide a no answer timer;

– Mid call event (DTMF or out of band information). The CSE shall specify the digit string(s) or the out of band information for which the instruction is valid. Out-band information may be detected during alerting phase of the call;

– Change of basic service.

– The party in the call for which the event shall be detected and reported (calling or called party);

– The type of monitoring (control or notification).

– Order in-band user interaction;

There shall be no restriction regarding the order of the above instructions or the number of times each of the above instructions can be repeated. Once the CSE has concluded issuing the above instructions, it shall issue one and only one of the following instructions:

– Bar the call (i.e. release the call prior to connection);

– Continue the call processing;

– Continue the call processing with modified information;

– Continue the handling of the calling party without routeing the call to the destination.

If a relationship for the call already exists and the CSE has activated this subsequent service event for this call and the collection of dialled digits event occurs the PLMN shall:

– Suspend call processing, notify the CSE and await further instructions.

The following information shall be provided to the CSE:

– Event met;

– The dialled digits;

– Type of monitoring.

When the PLMN has made contact with the CSE, the CSE shall be able to instruct the PLMN to act as described below.

– Perform charging activities;

– Activate subsequent control service events for the call. The CSE shall have the possibility to send the following information:

– The subsequent service event which shall be detected and reported:

– Called party alert;

– Called party connection;

– Call disconnection;

– Calling party abandon;

– Unsuccessful call establishment. In the case of no answer the CSE may provide a no answer timer;

– Change of basic service.

– The party in the call for which the event shall be detected and reported (calling or called party);

– The type of monitoring (control or notification).

– Order in-band user interaction;

– Bar the call (i.e. release the call prior to connection);

– Continue the call processing;

– Continue the call processing with modified information;

– Continue the handling of the calling party without routeing the call to the destination.

24.3.2 Procedure for trunk originated dialled services

The purpose of this procedure is to detect a call set-up request at the point where the called party number has been compared with the stored network service numbers, and allow the CSE to modify the handling of the call set-up request. Triggering of this procedure shall happen immediately after the procedure when dialled digits have been collected. If any other CAMEL dialogue has changed the called party number then the modified called party number is used for the conditional triggering check.

24.3.2.1 Initiation of contact with the CSE

If:

– The call set-up request occurs; and

– The call set-up request procedure is passed, and

– The PLMN is provisioned with network based service information.

Then the PLMN shall suspend call processing, make contact with the CSE and await further instructions.

24.3.2.2 Further processing of the call

If a relationship exists with a CSE, then when the PLMN has made contact with the CSE, the CSE shall be able to instruct the PLMN to act as described below:

– Perform charging activities The CSE is only allowed to include free format data in Call Data Records (refer to sect. 15.2, ‘Inclusion in charging records of information received from the CSE’);

– Order in-band user interaction. (Interaction between the service triggered from previous triggering may be needed to avoid duplicated guidance etc.).

Once the CSE has concluded issuing the above instructions, it shall issue one and only one of the following instructions:

– Release the call;

– Continue the call processing;

– Continue the call processing with modified information;

If no relationship exists with a CSE for the call, then when the PLMN has made contact with the CSE, the CSE shall be able to instruct the PLMN to act as described below:

– Collect additional digits (when overlap signalling occurs and the PLMN supports CSE requests for additional digits) as defined in subclause 24.3.1;

– Perform charging activities;

– Activate subsequent control service events for the call. The CSE shall have the possibility to send the following information:

– The subsequent service event which shall be detected and reported:

– Called party alert;

– Called party connection;

– Call disconnection;

– Calling party abandon;

– Unsuccessful call establishment. In the case of no answer the CSE may provide a no answer timer;

– Change of basic service.

– The party in the call for which the event shall be detected and reported (calling or called party);

– The type of monitoring (control or notification).

– Order in-band user interaction.

– Allow the call processing to continue unchanged;

– Allow the call processing with modified information;

– Continue the handling of the calling party without routeing the call to the destination;

– Release the call.

24.4 Calling party abandon

The purpose of this procedure is to manage an call set-up at the time it is terminated by the calling party before the call is established.

If the CSE has activated this subsequent service event for this call in notify mode and the calling party abandon event occurs the PLMN shall:

– Notify the CSE and continue.

The following information shall be provided to the CSE:

– Event met;

– Type of monitoring;

If the CSE has activated this subsequent service event for this call in request mode and the calling party abandon event occurs the PLMN shall suspend call processing, make contact with the CSE and await further instructions.

When the PLMN has made contact with the CSE in request mode, the CSE shall be able to instruct the PLMN to act as described below.

– Perform charging activities.

There shall be no restriction regarding the number of times the above instruction can be repeated. Once the CSE has concluded issuing the above instruction, it shall issue the following instruction:

– Continue the call processing.

24.5 Unsuccessful call establishment

If a relationship for the call already exists and the CSE has activated this subsequent service event for this call and the unsuccessful call establishment event occurs the PLMN shall:

– Suspend call processing, notify the CSE and await further instructions, or

– Notify the CSE and continue call processing.

In both cases above the following information shall be provided to the CSE:

– Event met;

– Type of monitoring;

– Cause for unsuccessful call establishment:

– Not reachable;

– Busy;

– No answer;

– Route select failure.

When the PLMN has made contact with the CSE, the CSE shall be able to instruct the PLMN to act as described below:

– Perform charging activities;

– Activate subsequent control service events for the call. The CSE shall have the possibility to send the following information:

– The subsequent service event which shall be detected and reported:

– Called party alert;

– Called party connection;

– Call disconnection;

– Calling party abandon;

– Unsuccessful call establishment. In the case of no answer the CSE may provide a no answer timer;

– Change of basic service.

– The party in the call for which the event shall be detected and reported (calling or called party);

– The type of monitoring (control or notification).

– Order in-band user interaction;

– Release the call;

– Continue the call processing;

– Continue the call processing with modified information.

24.6 Called party connection procedure

The purpose of this procedure is to manage a call set-up at the time when the called party answers and the call is successfully established.

If the CSE has activated this subsequent service event for this call and the called party connection event occurs the PLMN shall:

– Suspend call processing, notify the CSE and await further instructions, or

– Notify the CSE and continue call processing.

The following information shall be provided to the CSE:

– Event met;

– The party in the call for which the event is reported (only called party applicable);

– The charge indicator which will be used in the Call Data Record if available;

– Type of monitoring.

When the PLMN has made contact with the CSE, the CSE shall be able to instruct the PLMN to act as described below.

– Perform charging activities;

– Activate subsequent control service events for the call. The CSE shall have the possibility to send the following information:

– The subsequent service event which shall be detected and reported:

– Call disconnection;

– Mid call event (DTMF or out of band information). The CSE shall specify the digit string(s) or the out of band information for which the instruction is valid. The out-band information may be detected during alerting phase. The detection of the mid call event shall be limited to VPLMN only);

– Change of basic service.

– The party in the call for which the event shall be detected and reported (calling or called party);

– The type of monitoring (control or notification).

– Order in-band user interaction.

– Release the call;

– Continue the call processing.

24.7 Mid call procedure

See subclause 5.7, Consider “VPLMN” of 5.7 as “PLMN” and “served subscriber” of 5.7 as “trunk originated call”.

24.8 Call disconnection procedure

The purpose of this procedure is to manage the actions on disconnection of an established call. This procedure is applicable to any party in the call.

If the CSE has activated this subsequent service event for this call and the call disconnection event occurs the PLMN shall:

– Suspend call processing, notify the CSE and await further instructions, or

– Notify the CSE and continue call processing.

The following information shall be provided to the CSE:

– Event met;

– The party in the call for which the event is reported;

– Type of monitoring;

– Disconnection reason.

When the PLMN has made contact with the CSE, the CSE shall be able to instruct the PLMN to act as described below:

– Perform charging activities

– Activate subsequent control service events for the call. The CSE shall have the possibility to send the following information:

– The subsequent service event which shall be detected and reported:

– Called party alert;

– Called party connection;

– Call disconnection;

– Calling party abandon;

– Unsuccessful call establishment. In the case of no answer the CSE may provide a no answer timer;

– Mid call event (DTMF or out of band information). The CSE shall specify the digit string(s) or the out of band information for which the instruction is valid;

– Change of basic service.

– The party in the call for which the event shall be detected and reported (calling or called party);

– The type of monitoring (control or notification).

– Order in-band user interaction;

– Continue the call processing, i.e. release the call;

– Continue the call processing with modified information.

24.9 CSE initiated call release procedure

Following the CAMEL processing of the call set-up request procedure it shall be possible for the CSE to initiate a call release at any moment of the call.

To use this procedure:

– The PLMN shall have reported an initial service event to the CSE and be waiting for instructions from the CSE, or

– The CSE shall be waiting for the report of any subsequent service event (with ”Type of monitoring” set to control).

24.10 Called party alert reporting procedure

The purpose of this procedure is to manage a call set-up at the time when the called party is alerted.

If the CSE has activated this service event for this call and the called party alert event occurs the PLMN shall:

– Suspend call processing, notify the CSE and await further instructions, or

– Notify the CSE and continue call processing.

The following information shall be provided to the CSE:

– Event met;

– The party in the call for which the event is reported (only called party applicable);

– Type of monitoring.

When the PLMN has made contact with the CSE, the CSE shall be able to instruct the PLMN to act as described below:

– Perform charging activities;

– Activate subsequent control service events for the call. The CSE shall have the possibility to send the following information:

– The service event which shall be detected and reported:

– Calling party abandon;

– Unsuccessful call establishment. In the case of no answer the CSE may provide a no answer timer;

– Call disconnection;

– Mid call event (DTMF);

– Called party connection

– Change of basic service.

– The party in the call for which the event shall be detected and reported;

– The type of monitoring (control or notification).

– Order in-band user interaction with the calling party.

– Continue the call processing.

24.11 Change of basic service

When the CSE has instructed the PLMN to arm the change of basic service event, the PLMN shall report the event when the basic service changes. It shall be possible for the CSE to instruct the PLMN to re-arm the change of basic service event when it is encountered. The CSE may arm this event in the various phases of the call (as specified in this specification)– however the PLMN reports the basic service changes in the active phase of the call only.

If the CSE has activated this service event for this call and a change of basic service event occurs the PLMN shall:

– Notify the CSE and continue call processing.

The following information shall be provided to the CSE:

– Event met;

– Type of monitoring;

– Event specific data;

– Basic service:

– Charge result if charging supervision is provided:

When the PLMN has made contact with the CSE, the CSE shall be able to instruct the PLMN to act as described below:

– Perform charging activities;

– Activate other control service events for the call. The CSE shall have the possibility to send the following information:

– The service event which shall be detected and reported:

– Change of basic service.

– The party in the call for which the event shall be detected and reported;

– The type of monitoring (notification).

There shall be no restriction regarding the order of the above instructions or the number of times each of the above instructions can be repeated.

Annex A (normative):
Void

Annex B (normative):
Procedures for IP multimedia sessions