Content for  TS 23.247  Word version:  19.1.0

AF of content provider initiates MBS Session Update to a NEF/MBSF, e.g. to update MBS service area and/or update MBS Service Information (as defined in clause 6.14), or to activate or deactivate an MBS session. AF may provide updated information for an MBS session (identified by MBS session ID) by sending an Nnef_MBSSession_Update Request (MBS Session ID, [MBS Service Information], [MBS service area], [MBS session state (active/inactive)], [NR RedCap UE Information]). If geographical area information or civic address information was provided by the AF as MBS service area, NEF/MBSF translates the MBS service area to Cell ID list or TAI list and if the MBS session is also intended for NR NTN the NEF/MBSF derives the NR NTN Intended Service Area from geographical area information as defined in clause 6.21. For broadcast communication, the AF may subsequently update "NR RedCap UE Information" parameter.

NEF checks authorization of AF.

NEF/MBSF sends Nmbsmf_MBSSession_Update Request to MB-SMF forwarding the updated information received from the AF in step 1. If the MBSF acts as the MBS security function for multicast as defined in TS 33.501, it may provide an updated multicast session security context for the MBS session in the Nmbsmf_MBSSession_Update Request. If the MBS service area is not covered by the MB-SMF service area of the MB-SMF, the MB-SMF reduces the MBS service area to be within the MB-SMF service area and continues the procedure with the reduced MBS service area. For broadcast communication, the NEF/MBSF forwards "NR RedCap UE Information" parameter to the MB-SMF, if received. For broadcast communication, if the NEF/MBSF determines based on local configuration about the received service area that the MBS session is to be transmitted over NR NTN, and if the MBS service area received in step 8 is geographical area information , the MBS service area sent by the NEF/MBSF to MB-SMF may also include a NR NTN Intended Service Area in combination with a TAI list and/or cell ID list.

The MB-SMF derives any updated QoS parameters locally under consideration of the updated MBS Service Information. This may lead to addition of new MBS QoS Flow(s), removal of existing MBS QoS Flow(s) or update of existing MBS QoS Flow(s).

MB-SMF may need to update MB-UPF, e.g. if new MBS QoS Flow is to be created, or existing MBS QoS Flow is to be deleted.

For broadcast communication, the MB-SMF continues the procedure towards the AMF and NG-RAN as specified in clause 7.3.3. For multicast communication, the MB-SMF continues the procedure towards the AMF and NG-RAN as specified in clause 7.2.5 (for service activation/deactivation), clause 7.2.6 (for QoS updates and service area updates).

If an MBS service area is being updated, the MB-SMF stores the new service area in its profile at the NRF.

MB-SMF responds to the NEF/MBSF with a Nmbsmf_MBSSession_Update Response ([Information of area reduction]). If the MB-SMF reduces the MBS service area in step 3, the MB-SMF includes result information in the response indicating that the MBS service area cannot be covered by the MB-SMF service area of the MB-SMF, and includes the Information of area reduction that relates to the reduced MBS service area.

NEF/MBSF responds to the AF with a Nnef_MBSSession_Update Response ([MBS service area information]). If the NEF/MBSF receives the result information in step 9 indicating that the MBS service area cannot be covered by the MB-SMF service area of the MB-SMF, the NEF/MBSF includes that result information, and the Information of area reduction.

Same as in Figure 7.1.1.6-1.

For the interaction with the PCF in this procedure, the NEF/MBSF applies the same decision that was taken in step 10 in Figure 7.1.1.3-1 during the MBS Session Creation with PCC procedure unless the MBS session update only relates to an activation or deactivation of the MBS session and/or an MBS service area update and thus no PCF interactions are required. If the NEF/MBSF decided to interact with the PCF, steps 4 to 6 are performed and in step 7 an indication that the PCF has to be contacted is provided, and MBS Service Information is not provided to the MB-SMF. If the NEF/MBSF decided not to interact with the PCF, steps 4 to 6 are skipped and MBS Service Information is provided to the MB-SMF in step 7.

NEF/MBSF sends an Npcf_MBSPolicy_Authorization_Update Request (application session context, [MBS Service Information]) to the PCF forwarding the updated information received from the AF in step 1.

The PCF determines whether the update is authorized and if the update is authorized, the PCF derives the update for the QoS parameters based on the received MBS Service Information and determines whether this new QoS is allowed. If the new QoS is allowed, the PCF updates the policy information for the MBS session (as defined in clause 6.10) accordingly. If the policy information for the MBS session has changed, the PCF shall provide an indication that the PCF has to be contacted.

The PCF sends an Npcf_MBSPolicy_Authorization_Update Response (Result indication, [indication that the PCF has to be contacted]) to the NEF/MBSF. If the update is not authorized or the new QoS is not allowed, the PCF indicates so in the response to the NEF/MBSF which in turn informs the AF about it (by sending the Nnef_MBSSession_Update Response) and ends this procedure.

The NEF/MBSF sends Nmbsmf_MBSSession_Update Request to the MB-SMF forwarding the updated information received from the AF in step 1. If the NEF/MBSF has decided not to interact with the PCF, the NEF/MBSF send the indication that the PCF has to be contacted, in addition. If the NEF/MBSF has decided to interact with the PCF and thus provided the updated MBS Service Information to the PCF in step 4, the updated MBS Service Information is not forwarded. The NEF/MBSF forwards the indication that the PCF has to be contacted, if received from the PCF.

If the MB-SMF does not receive the indication that the PCF has to be contacted, the MB-SMF decides whether to interact with the PCF. If it decides not to interact with the PCF, it continues with step 11. Otherwise, the MB-SMF sends an Npcf_MBSPolicyControl_Update Request (MBS Policy Association ID, [MBS Service Information]) for the MBS session towards the PCF. The MB-SMF forwards the MBS Service Information to the PCF if received from the NEF/MBSF in the previous step 7. If PCF receives MBS Service Information from the MB-SMF, the PCF performs the subsequent step 9. If the PCF does not receive MBS Service Information from the MB-SMF, the PCF identifies any updated policy information for the MBS session (as defined in clause 6.10) corresponding to the MBS Session ID received from the MB-SMF and continues with step 10.

The PCF determines whether the update is authorized and if the update is authorized, the PCF derives the update for the QoS parameters based on the received MBS Service Information and determines whether this new QoS is allowed. If the new QoS is allowed, the PCF updates the policy information for the MBS session (as defined in clause 6.10) accordingly.

The PCF responds with Npcf_MBSPolicyControl_Update Response ([updated policy information for the MBS session], Result indication). If the request is not authorized or the required QoS is not allowed, the PCF indicates so in the response to the MB-SMF which in turn informs the AF about it (by sending the Nmbsmf_MBSSession_Update Response) and ends this procedure.

Same as steps 5-10 in Figure 7.1.1.6-1.