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

• Attach procedure: a subscriber requests to register to the GPRS network;
• PDP Context Establishment: a subscriber requests the activation of a Packet Data Protocol Context;
  • PDP Context Establishment Acknowledgement: the SGSN has received an acknowledgement from the GGSN for that request.
• Change of Position (Session): a subscriber who has an active GPRS Session changes position to another SGSN;
• Change of Position (PDP Context): a subscriber who has an active PDP Context changes position to another SGSN.

The purpose of this procedure is to detect a request from a GPRS subscriber to attach to the data network and allow the CSE to modify the handling of the attach request. If (according to the CSI):

• The subscriber is provisioned with a CAMEL based service, relevant for GPRS data transmission; and
• The attach request is set as a trigger detection; and
• The attach request occurs

Then the VPLMN shall suspend attach processing, make contact with the CSE and await further instructions. When the VPLMN has made contact with the CSE, the CSE shall be able to instruct the VPLMN to act as described below:

• Activate subsequent control service events for the period being attached to the data network. The CSE shall have the possibility to send the following information:
  • The subsequent service event which shall be detected and reported:
    • PDP Context Establishment request;
    • PDP Context Establishment Acknowledgement;
    • Change of position (session);
    • Detach;
    • Type of monitoring
  • Perform charging activities (amongst others defining a time threshold). The charging activities shall apply to the GPRS Session.

There shall be no restriction regarding 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:

• Reject the attachment request;
• Continue the processing.

The purpose of this procedure is to manage a request from the subscriber to activate a Packet Data Protocol. . Multiple contacts to the CSE may be made in parallel due to PDP Context Establishment events being detected whilst a GPRS subscriber is attached to the network. If either (according to the CSI):

• The subscriber is provisioned with a CAMEL based service relevant for GPRS data transmission; and
• The PDP activation request is set as a trigger detection, and
• The PDP Activation request occurs

Or the CSE has activated this service event for the attached subscriber and the PDP activation event occurs then the VPLMN shall either

• Suspend processing, make contact with the CSE and await further instructions, or
• Send a notification and continue.

When the PDP Context Establishment event occurs, it shall be reported as a Subsequent Service Event, if armed by the CSE. If it is not armed by the CSE, it shall be reported as an Initial Service Event, if statically armed in the subscription information.

The purpose of this procedure is to manage a confirmation from the GGSN to activate a Packet Data Protocol. Multiple contacts to the CSE may be made in parallel due to PDP Context Establishment Acknowledgement events being detected whilst a GPRS subscriber is attached to the network. If either (according to the CSI):

• The subscriber is provisioned with a CAMEL based service relevant for GPRS data transmission, and
• The PDP Context Establishment acknowledgement is set as a trigger detection point, and
• The PDP Context Establishment Acknowledgement request occurs

Or the CSE has activated this service event for the attached and / or active subscriber and the PDP activation acknowledgement event occurs then the VPLMN shall either

• Suspend processing, make contact with the CSE and await further instructions, or
• Send a notification and continue.

When the PDP Context Establishment Acknowledgement event occurs, it shall be reported as a Subsequent Service Event, if armed by the CSE. If it is not armed by the CSE, it shall be reported as an Initial Service Event, if statically armed in the subscription information.

The purpose of this procedure is to detect a request from the GPRS subscriber to update the routeing area. A change of position can be an intra-SGSN routeing area update (update within the same SGSN) or an inter-SGSN routeing area update (update from one SGSN to another SGSN). When an intra-SGSN routeing area update occurs, then this event shall be reported as a Subsequent Service Event, if it was armed by the CSE. When an inter-SGSN routeing area update occurs, then this event shall be reported as an Initial Service Event, if it was statically armed in the GPRS Subscription data. In this case, the previous relationship shall be terminated. The change of position event can be armed and reported for a GPRS Session relationship and for a PDP Context relationship.

The purpose of this procedure is to control the amount of data transmitted by and transmitted to the served subscriber or the used time per GPRS Session or PDP Context. The threshold is valid either for the GPRS session or for one PDP Context of the subscriber only. If the subscriber controls simultaneous PDP Contexts, thresholds per GPRS session or PDP Context may be defined. For correct performance, the threshold shall be available for the first time as a response to a GPRS Session establishment (if valid for the GPRS Session) or as a response to a PDP Context Establishment (if valid for the PDP Context). Subsequent thresholds may be received immediately after the expiry of the previous threshold or at change of QoS. The type of threshold is indicated per GPRS session or PDP Context as:

• A maximum amount of data transmitted by and transmitted to the subscriber;
• A granted time to transmit and receive data.

A threshold is reached within a GPRS session or PDP Context, when:

• The total amount of data transmitted by and transmitted to the subscriber reaches the granted data volume, or
• The allowed time for the GPRS Session or PDP Context has elapsed.

If the CSE has defined a threshold for a GPRS Session or PDP Context and the threshold has been reached, then the VPLMN shall inform the CSE. The VPLMN shall not suspend the transmission of data packets to and from the GPRS terminal. The VPLMN shall immediately restart counting the amount of data transmitted by and transmitted to the GPRS terminal and restart timing the duration of the GPRS Session or PDP Context. The following information shall be provided to the CSE if available:

• Charge result (elapsed time or total amount of data transmitted);
• The GPRS session or PDP Context for which the event is reported;
• GPRS Session or PDP Context-Active indicator.

When the VPLMN has reported the reaching of the threshold to the CSE, the CSE shall be able to do the following (assuming the continuation of the applicable dialogue):

• Perform charging activities (including the defining of a new threshold or time limit). GPRS Session related charging activities may be sent only if a GPRS Session related charging threshold was reported.
• Activate subsequent control service events for the PDP Context or GPRS Session. The CSE shall have the possibility to send the following information:
  • The subsequent service event which shall be detected and reported:
    • PDP deactivation;
    • Change of Position (PDP Context);
    • Change of Position (Session): this event may be armed only if the PDP deactivation event is reported within a GPRS Session relationship;
    • Detach; this event may be armed only if the data or time threshold event is reported within a GPRS Session relationship.
• The GPRS session or PDP Context for which the event shall be monitored and reported;
• The type of monitoring (only monitor mode is allowed in this case).

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, issue one and only one of the following instructions (provided the GPRS session or PDP context has not been released):

• Release the PDP Context;
• Release the GPRS Session; this instruction may be given only if the data or time threshold event is reported within a GPRS Session relationship;
• Continue the GPRS session or PDP Context.

The purpose of this procedure is to detect a request from the subscriber to release a Packet Data Protocol. If the CSE has activated this subsequent service event for the attached subscriber and the PDP deactivation event occurs then the VPLMN shall suspend processing, make contact with the CSE and await further instructions or send a notification and continue. The following information shall be provided to the CSE:

• Event met;
• The PDP Context for which the event is reported;
• Type of monitoring.

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

• Activate subsequent control service events for the GPRS session. The CSE shall have the possibility to send the following information:
  • The subsequent service event which shall be detected and reported:
    • Detach Procedure: this event may be armed only if the PDP deactivation event is reported within a GPRS Session relationship;
    • Change of Position (Session): this event may be armed only if the PDP deactivation event is reported within a GPRS Session relationship.
  • The type of monitoring.
• Perform charging activities; GPRS Session related charging instructions may be sent only if the PDP deactivation event is reported within a GPRS Session relationship

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 send one and only one of the following instruction:

• Release the GPRS Session: this instruction may be given only if the PDP deactivation event is reported within a GPRS Session relationship;
• Continue the processing.

The purpose of this procedure is to detect a request from a GPRS subscriber to detach from the data network. If the CSE has activated this subsequent service event for the attached subscriber and the Detach event occurs, then the VPLMN shall suspend processing, make contact with the CSE and await further instructions or send a notification and continue. The following information shall be provided to the CSE, if available:

• Event met;
• Type of monitoring.

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

• Perform charging activities. Only Session related charging instructions may be sent.

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 send the following instruction:

• Continue the processing.

Following the CAMEL processing of the GPRS attach procedure it shall be possible for the CSE to initiate a GPRS detach at any time. To use this procedure, there shall be a control relationship between the CSE and the GPRS session.

Following the CAMEL processing of the PDP Context Establishment procedure or PDP Context Establishment Acknowledgement procedure it shall be possible for the CSE to initiate PDP Context deactivation at any time. To use this procedure, there shall be a control relationship between the CSE and the PDP Context.

The CSE may request the VPLMN to report a change in the Quality of Service (QoS) for a specific PDP Context. When a QoS change occurs, then the VPLMN shall send a notification to the CSE and continue. The following information shall be provided to the CSE:

• Charge result - this may be elapsed time or the total amount of data transmitted by and transmitted to the subscriber
  • Quality of Service;
  • PDP Context state.

When the CSE receives the notification of change of QoS, it may instruct the VPLMN to act as follows:

• Perform charging activities (including the defining of a new threshold). GPRS Session related charging instructions may be sent only if the change of PDP Context QoS event is reported within a GPRS Session relationship;
• Activate subsequent control service events for the PDP Context or GPRS Session. The CSE shall have the possibility to send the following information:
  • The subsequent service event which shall be detected and reported:
    • PDP deactivation;
    • Change of Position (PDP Context);
    • Change of Position (Session): this event may be armed only if the change of PDP Context QoS event is reported within a GPRS Session relationship;
    • Detach Procedure: this event may be armed only if the change of PDP Context QoS event is reported within a GPRS Session relationship.
  • The PDP Context for which the event shall be monitored and reported;
  • The type of monitoring (only monitor mode is allowed in this case).

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:

• Release the PDP Context;
• Release the GPRS Session: this instruction may be given only if the change of PDP Context QoS event is reported within a GPRS Session relationship;
• Continue the PDP Context.

The CSE can perform the following charging activities: