C.2 Object Distribution Method with push-based ingest

26.5023GPP5G Multicast-Broadcast User Service ArchitectureRelease 17TS

C.2.1 DASH content distribution with push-based ingest

This example focuses on DASH content distribution with push-based ingest. The DASH segment packager continuously publishes media segments to the MBSTF as they become available. Media segments from all relevant DASH Adaptation Sets and Representations are multiplexed into the same MBS Distribution session. The data model parameters are provided in Figure C.2.1-1.

Figure C.2.1-1: DASH content distribution with push-based ingest

The DASH segment packager is configured to use the Object ingest base URL to upload media segments using HTTP. Each segment is identified by a unique URL relative to this base. The distribution URL generated by the MBSTF is formed by replacing the Object ingest base URL prefix with the value of Object distribution base URL.

EXAMPLE:

URL of ingested object: https://<mbstf>:443/base/<tmgi#1>/video/segment_1000.m4s

URL of distributed object: https://<CSP#1>/srv1/video/segment_1000.m4s

where:

– The string ip_mbupf#A:port#A refers to the IP address and port for the tunnel at which the MB-UPF expects the data for the MBS Session.

– The string <mbstf> refers to the IP address or the hostname of the MBSTF function.

– The string <tmgi#1> refers to the TMGI, which is assigned to the MBS Session.

NOTE: The TMGI of the MBS Session is used in this example to make the ingest URL uniqueue within the 5G System. Other solutions to ensure uniqueness are possible.

– The term <CSP#1> refers to a fully qualified domain name of the CSP.

The MBSF needs access to the MPD URL in order to compile the MBS Distribution Session Announcement. The MBSF may also modify the contents of the MPD ("conditioning") before compiling it into the Session Announcement and/or publishing it for retrieval at reference point MBS‑4‑UC.

The MBSTF does not need to inspect the contents of the DASH MPD.

The MBSTF uses a unicast tunnel to inject the generated MBS data into the MB-UPF at reference point Nmb9, using the Maximum bit rate parameter to pace these packets.

C.2.2 DASH content distribution with push-based ingest using separate MBS Distribution Sessions for audio and video

This example focuses on DASH content distribution with push-based ingest. The DASH segment packager continuously publishes media segments to the MBSTF as they become available. In this case, media segments from the video and audio Adaptation Sets are multiplexed into different MBS Distribution Sessions. In this case, the MBS User Service is provisioned to distribute the audio and video segments on separate MBS Distribution Sessions, with the two resulting MBS Distribution Sessions multiplexed onto the same MBS Session.

Figure C.2.2-1: DASH content distribution with push-based ingest
using separate MBS Distribution Sessions for audio and video

For each MBS Session, the MBSTF uses a specific Maximum bit rate parameter to pace the packets towards the MB-UPF (here 5 Mbps for video segments and 200 kbps for audio segments). For the ingest session, two separate Object ingest base URLs are provided, namely:

https://<mbstf>:443/base/<tmgi#1#1>/ and

https://<mbstf>:443/base/<tmgi#1#2>/

The strings <tmgi#1#1> and <tmgi#1#2> are used to make the ingest URLs unique within the 5G System. The last portion is a suffix for the individual MBS Distribution Session. The usage of the TMGI of the MBS Session is one example to make the ingest URL unique within the 5G System.

The MBSTF uses the same unicast tunnel to inject the data into the MB-UPF at reference point Nmb9, so that the data is distributed via the same MBS Session.

C.2.3 Generic object distribution with push-based ingest

This example focuses on generic object distribution using push-based ingest. In this case, a series of objects are pushed by the MBS Application Provider (AF/AS) into the MBSTF where an MBS Distribution Session is provisioned to use the OBJECT_SINGLE operating mode, which requires no manifest.

Figure C.2.3-1: Generic object distribution with push-based ingest

The case is very similar to the previous DASH content distribution cases, with the difference that no Object acquisition identifiers are provisioned. Any object pushed to the Object ingest base URL nominated by the MBSF is distributed in the MBS Distribution Session by the MBSTF after substituting the Object ingest base URL prefix with the Object distribution base URL.