Scope Project Roadmap GitHub Repos Releases Tutorials Video Library Requirements

Scope

In the context of 3GPP standards, the Multicast Broadcast Services System, MBS System, is designed to support multicast and broadcast services in 5G networks. It introduces a flexible architecture that supports both Multicast (for specific groups with high reliability) and Broadcast (for wide-area distribution to all users), allowing the network to dynamically switch between point-to-point and point-to-multipoint delivery. While the MBS System handles the heavy lifting of moving data through the 5G core and radio, MBS User Services defines how that content is actually packaged, discovered, and consumed by the end-user’s application.

Technical documentation providing context to this project can be found in the link below.

Tech: Multicast and Broadcast Services in 5G Networks

A list of relevant specifications can be found in the link below.

Standards: 5G Multicast Broadcast Services

Standards: Multimedia Delivery Protocols

What is being implemented?

Some of the functional entities of the MBS System and MBS User Services, including support in the application provider side, the 5GC, NG-RAN and UE.

MBS User Services

Features under implementation

The 5G-MAG Reference Tools for MBS User Services add the following functionality:

MBSTF Distribution Session management (e.g. by an MBSF) via reference point Nmb2.
Ingest of objects by the MBSTF from the MBS Application Provider (AF/AS) via reference point Nmb8, using either a pull- or push-based object acquisition method.
Delivery of ingested objects in a FLUTE Session multicast sent as multicast ALC packets from an MBSTF to an MB-UPF via a reference point Nmb9 unicast tunnel.

The following features are supported:

MB-SMF TMGI Service API (Following 3GPP TS 29.532 V17.4.0)
- TMGI Allocate Service operation
- TMGI Deallocate Service operation
MB-SMF MBS Session Service API (Following 3GPP TS 29.532 - Release 17.4.0)
- MBS Session Create Service operation
- MBS Session Release Service operation
MB-SMF PFCP Session Establishment extensions (Following 3GPP TS 29.244 - Release 17.9.0)
- PFCP Session Establishment Request extensions
MB-UPF PFCP Session Establishment extensions (Following 3GPP TS 29.244 - Release 17.9.0)
- PFCP Session Establishment Response extensions
Multicast/Broadcast Service Transport Services (MBSTF) (Following 3GPP TS 29.581 V18.5.0)
- Object distribution method
  - Single shot operating mode: Individual objects are sent once in a FLUTE Session by the MBSTF
    - Pull-based object acquisition (MBSTF pulls objects from a media server)
    - Push-based object acquisition (objects are pushed into the MBSTF)
  - Streaming operating mode: Objects are scheduled and sent in real time according to a presentation manifest, such as a DASH MPD.
    - Pull-based object acquisition (MBSTF pulls a Service Entry Point object, such as a presentation manifest, and then schedules the pulling of further objects, such as media segments and updates of the presentation manifest)
    - Push-based object acquisition (MBSTF waits for a Service Entry Point object, such as a presentation manifest, to be pushed to it, and then schedules the pulling of media segment objects)
    - For this operating mode, the supported Service Entry Point formats are:
      - MPEG-DASH MPD (live profile only).

The following features are not yet supported:

AMF MBS Broadcast Service API (Following 3GPP TS 29.518 V17.11.0)
- MBS Broadcast ContextCreate Service operation
- MBS Broadcast ContextRelease Service operation
AMF NGAP extensions (Following 3GPP TS 38.413 - Release 17.6.0)
- BROADCAST SESSION SETUP REQUEST
gNB NGAP extensions (Following 3GPP TS 38.413 - Release 17.6.0)
- BROADCAST SESSION SETUP RESPONSE
NRF NFDiscovery Service API extensions (Following 3GPP TS 29.510 - Release 17.11.0)
- MB-SMF TMGI Service API extensions
- MB-SMF MBS Session Service API extensions
- AMF MBS Broadcast Service API extensions
MBSTF Distribution Session management (Following 3GPP TS 29.581 V18.5.0)
- Packet distribution method
  - Use direct multicast packet ingest by the MB-UPF at reference point N6mb instead for now.
- Object distribution method
  - Collection operating mode: One or more objects described by a simple manifest are sent once in the FLUTE Session.
  - Carousel operating mode: One or more objects described by a simple manifest are repeatedly sent in the FLUTE Session according to a schedule.
  - Streaming operating mode: Objects are sent in a FLUTE Session in real time according to a schedule specified in a streaming presentation manifest.
    - Presentation manifest types other than MPEG-DASH MPD (live profile).
- Status notification subscription

MBS System

MBS development over Open5GS

The 5G-MAG Reference Tools for MBS currently target:

MBS Session provisioning in the MB-SMF (e.g. by an MBSF) via reference point Nmb1.
Direct multicast data ingest by the MB-UPF from an AF/AS via reference point N6mb.
Shared delivery of multicast packets from the MB-UPF via individual GTP-U tunnels to one or more gNodeBs in the 5G Core.
Point-to-Multipoint (PTM) delivery of multicast packets from a gNodeB to UEs via the RAN.

High-level architectures

5G Multicast Broadcast Services (MBS)

5G Multicast Broadcast Services: Repositories Multimedia content delivery protocols: Repositories 3GPP RAN and Core Platforms: Repositories Common Tools: Repositories

5G Multicast Broadcast Services (MBS) with 5GC Service Consumers

5G Multicast Broadcast Services: Repositories Multimedia content delivery protocols: Repositories 5GC Service Consumers: Repositories 3GPP RAN and Core Platforms: Repositories Common Tools: Repositories

Docker deployment support

Docker-Compose setups are provided to run the 5GC Network Functions related to MBS in Docker container environments.

5G Multicast Broadcast Services: Repositories