5.2.1 Basic principles and definitions

32.2813GPPAnnouncement serviceCharging managementRelease 17Telecommunication managementTS

The CHF/OCS may provide information in charging messages that describe video or audio announcements which can be rendered to a subscriber involved in an IMS session at different stages of interactions with CHF/OCS.

When receiving announcement information provided by CHF/OCS, the AS or the IMS-GWF shall use the procedures defined in clause 10.2.2 of TS 24.229 [204] and TS 24.628 [244] in order to deliver the required announcement in accordance with the provided announcement information.

CHF/OCS can provide announcement information upon interaction with the AS or the IMS-GWF, during different phases of an IMS session:

– At IMS session initiation, before the IMS session is allowed to continue and no quota is granted, or before the IMS session is allowed to continue and use granted quota;

– During an ongoing established IMS session, with media components between the parties of the session, on quota allocation control process;

– At an IMS session termination due to final quota consumption.

Announcements provided by CHF/OCS are driven by quota allocation during the IMS session, and controlled by an indication on when they shall be played:

– Pre-quota announcement shall be played prior to any quota consumption (i.e. immediately);

– Mid-quota announcements shall be played at a specified duration before granted quota is exhausted, which ranges from non-zero value smaller than the granted quota.

– Post-quota announcements shall be played upon granted quota exhaustion

CHF/OCS can provide information for one or more announcements in the same charging message.

A CHF/OCS-provided announcement is delivered to a single party of an IMS session. CHF/OCS indicates to which party the announcement shall be played. This can be the served party or the remote party. When the privacy indicator for the announcement is set to "private", the announcement shall be played only to the requested party. The handling toward the other party during announcement playback is determined by the AS or the IMS-GWF internal logic.

The AS or the IMS-GWF shall control delivery of the announcements based on the announcement content information provided by the CHF/OCS. The AS or the IMS-GWF shall use the procedures in TS 24.628 [244] for announcement delivery. When the AS or the IMS-GWF are separate from the MRFC, the AS or the IMS-GWF shall support one or more of the control methods for announcement referenced in clause 10.2.2 of TS 24.229 [204], regardless of the announcement content information provided by the CHF/OCS. The AS or the IMS-GWF is responsible for determining the MRF handling the announcement.

Announcement information indicates whether any of the granted quota shall be used by the AS or the IMS-GWF during the time the announcement is connected. If not explicitly indicated in the announcement information by the CHF/OCS, it is up to the service logic implemented in the AS or the IMS-GWF to use or not the granted quota.

For announcements delivered by the AS or the IMS-GWF during an IMS established session, the existing media shall be suspended while the announcement media is played.