B.2 Object Distribution Method

26.5023GPP5G Multicast-Broadcast User Service ArchitectureRelease 17TS

B.2.1 Object Distribution Method with pull-based ingest

Figure B.2.1-1 illustrates a setup in which the MBS Application Provider (AF/AS) provides an object manifest to the MBSF listing the URLs of objects to be ingested and distributed. This is passed to the MBSTF at reference point Nmb2, and the MBSTF then fetches these objects using HTTP. The MBSTF handles all MBS-related complexity, e.g. converting the HTTP message payload into an IP multicast suitable protocol, adding AL-FEC, etc. The AF/AS delegates to the MBSF the delivery of MBS Service Announcement metadata to the MBS Client (i.e. IP multicast protocol details, etc).

Figure B.2.1-1: Object Distribution Method using Pull ingest mode (HTTP GET)

The following Parameters are used by the MBS Application Provider (AF/AS) at reference point Nmb10 to provision this setup:

– Distribution method is set to Object.

– Object acquisition method (property specific to the distribution method) is set to Pull.

– Operating mode is set to OBJECT_SINGLE or OBJECT_COLLECTION or OBJECT_CAROUSEL or OBJECT_STREAMING, as appropriate.

– OBJECT_SINGLE: Object acquisition identifiers refers to a single object.

– OBJECT_COLLECTION: Object acquisition identifiers refers to a manifest describing the set of objects to be distributed once.

– OBJECT_CAROUSEL: Object acquisition identifiers refers to a manifest describing the set of objects and their repetition and update pattern.

– OBJECT_STREAMING: Object acquisition identifiers refers to a presentation manifest such as a DASH MPD. The MBSTF pulls the objects according to the presentation manifest.

B.2.2 Object Distribution Method with push-based ingest

Figure B.2.2-1 illustrates a setup in which the MBS Application Provider (AF/AS) pushes objects directly into the MBSTF at Nmb8 using HTTP PUT. The MBSTF handles all MBS-related complexity, e.g. converting the HTTP message payload into an IP multicast suitable protocol, adding AL-FEC, etc. The AF/AS delegates MBS delivery of Service Announcement metadata destined for the MBS Client (i.e. DASH MPD, IP multicast protocol details, etc.) to the MBSTF via MBSF.

Figure B.2.2-1: Object Distribution Method using Push ingest mode (HTTP PUT)

The following MBS Distribution Session properties are used by the MBS Application Provider (AF/AS) at reference point Nmb10 to provision this setup:

– Distribution method is set to Object.

– Object acquisition method is set to Push.

– Operating mode is set to OBJECT_SINGLE or OBJECT_STREAMING, as appropriate.

– OBJECT_SINGLE: Each pushed object is distributed once.

– OBJECT_COLLECTION: Not used.

– OBJECT_CAROUSEL: Not used.

– OBJECT_STREAMING: Each pushed object is distributed once.

– Distribution operating mode is set to File or Collection or Carousel or Real-time, as appropriate.

– Object acquisition identifiers contains the Push base URL used to ingest objects. The MBSF provides the Push base URL (property specific to the distribution method) to the MBS Application Provider (AF/AS).

– Distribution base URL contains the base URL for the objects. The MBSF replaces the Push base URL part of the object ingest URL with the value of the Distribution base URL for inclusion in FLUTE FDT instance(s) and (in some cases) in the Service Announcement.