5.2.3 Message flows and types for converged charging

32.2813GPPAnnouncement serviceCharging managementRelease 17Telecommunication managementTS

The different scenarios below focus on the different messages from/to the IMS NF (e.g. IMS AS) and corresponding interaction with the CHF.

The IMS related and Charging Data messages associated with these scenarios are shown primarily for general information and to illustrate the charging triggers. They are not intended to be exhaustive and they depend on operator configuration.

Editor’s Note: The naming and use of IMS NF is FFS. The flows needs further elaboration.

Scenario 1: Immediate announcement at start of session with establishment

Figure 5.2.3.1 shows the Charging Data messages that are required for which an immediate announcement is requested with successful session establishment.

Figure 5.2.3.1: Message sequence chart for immediate announcement at start of session with establishment

1) An initial Invite Request is received in the IMS NF.

1ch-a) The IMS NF sends a Charging Data Request [Initial] to the CHF with quota requested.

1ch-b) based on policies, the CHF opens a CDR related to the service and decides the announcement to be played.

1ch-c) The CHF grants authorization to IMS NF (CTF) for the service to start, with the reserved number of units and requests an announcement to be played to the calling party immediately. Announcement information may indicate whether the granted quota for the IMS session shall be used for playing the announcement.

2a) The IMS NF establishes a session between the calling party and a media resource for the requested announcement as per TS 24.628 [244] and TS 24.229 [204].

2b) The media resource plays the announcement to the calling party.

2c) When the announcement is complete, the IMS NF disconnects the session with the media resource as per TS 24.628 [244] and TS 24.229 [204].

3) The IMS NF forward the initial INVITE.

4) A final OK response is received in the IMS NF

4ch-a) If the trigger is active, the OK answer triggers a Charging Data Request [Update] in the IMS NF with quota requested. The used units during the announcement are either reported with quota managed indication if the indication in step 1ch-c is to use the quota granted for playing the announcement otherwise they are reported without quota managed indication.

4ch-b) based on policies, the CHF updates a CDR related to the service.

4ch-c) The CHF grants authorization to IMS NF (CTF) for the service to start, with the number of quotas.

5) The final OK answer is forwarded.

Scenario 2: Immediate announcement at start of session with termination

Figure 5.2.3.2 shows the Charging Data messages that are required for when an immediate announcement is requested with the termination of the session.

Figure 5.2.3.2: Message sequence chart for immediate announcement at start of session with termination

1) An initial SIP Invite Request is received in the IMS NF.

1ch-a) The IMS NF sends a Charging Data Request [Initial] to the CHF with quota requested.

1ch-b) based on policies, the CHF opens a CDR related to the service and decides the announcement to be played.

1ch-c) The CHF does not grant authorization to IMS NF (CTF) for the service to start, instead it requests an announcement to be played to the calling party immediately. No quota can be used by the IMS session for playing the announcement.

2a) The IMS NF establishes a session between the calling party and a media resource for the requested announcement as per TS 24.628 [244] and TS 24.229 [204].

2b) The media resource plays the announcement to the calling party.

2c) When the announcement is complete, the IMS NF disconnects the session with the media resource as per TS 24.628 [244] and TS 24.229 [204].

3) The IMS NF initiates session termination to the calling party by sending a BYE.

3ch-a) The IMS NF (CTF) sends a Charging Data Request [Termination] to the CHF with units used.

3ch-b) Based on policies, the CHF updates the CDR with charging data related to the service termination and the last reported units.

3ch-c) The CHF informs the IMS NF (CTF) on the result of the request.

4) The final answer to the BYE message is forwarded to the IMS NF ending the SIP dialog.

Scenario 3: Deferred announcement in session with continuation

Figure 5.2.3.3 shows the Charging Data messages that are required in the IMS NF for a deferred announcement during an established session, followed by session continuation.

Figure 5.2.3.3: Message sequence chart for deferred announcement in session with continuation

1) During an ongoing SIP session, a charging trigger encountered.

1ch-a) The IMS NF sends a Charging Data Request [Update] to the CHF with quota requested.

1ch-b) Based on policies, the CHF updates the CDR related to the service and decides the announcement to be played.

1ch-c) The CHF grant authorization to IMS NF (CTF) for the service to continue and requests an announcement to be played to the calling party prior to quota exhaustion. Announcement information may indicate whether the granted quota for the IMS session shall be used for playing the announcement.

2a) When the conditions are met for the requested announcement, the IMS NF establishes a session between the calling party and a media resource for the requested announcement as per TS 24.628 [244] and TS 24.229 [204].

2b) The media resource plays the announcement to the calling party.

2c) When the announcement is complete, the IMS NF re-connects the called party, disconnecting the session with the media resource as per TS 24.628 [244] and TS 24.229 [204].

Scenario 4: Deferred an announcement in session with session termination

Figure 5.2.3.4 shows the Charging Data messages that are required in the IMS NF for a deferred announcement during an established session, followed by session termination.

Figure 5.2.2.4: Message sequence chart for deferred announcement with session termination

1) During an ongoing session, a charging trigger encountered.

1ch-a) The IMS NF sends a Charging Data Request [Update] to the CHF with quota requested.

1ch-b) Based on policies, the CHF updates the CDR related to the service and decides the announcement to be played.

1ch-c) The CHF grant authorization to IMS NF (CTF) for the service to continue with a final quota indication and requests an announcement to be played to the calling party. No quota can be used by the IMS session for playing the announcement.

3) When end of quota is reached, the IMS NF initiates session termination to the called party by sending a BYE message.

4) The final answer to the BYE message is forwarded to the IMS NF ending the session with the called party. The IMS NF does not wait for this response before continuing the message sequence.

5a) The IMS AF establishes a session between the calling party and a media resource for the requested announcement as per TS 24.628 [244] and TS 24.229 [204].

5b) The media resource plays the announcement to the calling party.

5c) When the announcement is complete, the IMS NF disconnects the session with the media resource as per TS 24.628 [244] and TS 24.229 [204].

6) The IMS NF initiates session termination to the calling party by sending a BYE.

6ch-a) The IMS NF (CTF) sends a Charging Data Request [Termination] to the CHF with units used.

6ch-b) Based on policies, the CHF updates the CDR with charging data related to the service termination and the last reported units.

6ch-c) The CHF informs the IMS NF (CTF) on the result of the request.

7) The final answer to the BYE message is forwarded to the IMS NF ending the SIP dialog.