26.5023GPP5G Multicast-Broadcast User Service ArchitectureRelease 17TS
At this point, the MBS User Service Session is advertised to the MBSF Client, as shown in figure 5.4‑1 below.
Figure 5.4‑1: Call flow for MBS User Service advertisement/discovery
The steps are as follows:
1. The MBSF compiles a composite MBS User Service Announcement from the set of individual MBS Distribution Session Announcements compiled in step 14 of clause 5.3. The compiled MBS User Service Announcement describes the current set of MBS Distribution Sessions that comprise the active MBS User Data Ingest Session. The advertised start date–time is the next start time indicated in the MBS User Data Ingest Session schedule of active periods, or the current date–time if no schedule is provisioned.
2. The MBS User Service Announcement is distributed using one or more of the following mechanisms:
a. The MBS User Service Announcement is made available for unicast retrieval by the MBSF Client at reference point MBS‑5.
b. The MBS User Service Announcement is made available via a suitable multicast/broadcast Session Announcement Channel at reference point MBS‑4‑MC.
c. The MBS User Service Announcement is passed back to the MBS Application Provider by invoking the Nmbsf_MBSUserDataIngestSession_StatusNotify callback service operation at reference point Nmb10 (or Nmb5+N33, if invoked via the NEF).
As a result, the MBS Application Provider advertises the MBS User Service Announcement to the MBS-Aware Application by private means at reference point MBS‑8.
The MBSF may rescind an MBS User Service Announcement at any time for operational reasons.