The 5GMS Application Provider uses 5GMS for streaming services. It provides a 5GMS Aware-Application on the UE to make use of 5GMS Client and network functions using interfaces and APIs defined in 5GMS.
The architecture in Figure 4.1.1-1 represents the specified 5GMS functions within the 5G System (5GS) as defined in TS 23.501. Three main functions are defined:
5GMS AF: An Application Function as defined in clause 6.2.10 of TS 23.501, dedicated to 5G Media Streaming.
5GMS AS: An Application Server dedicated to 5G Media Streaming.
5GMS Client: A UE internal function dedicated to 5G Media Streaming. The 5GMS Client is a logical function and its subfunctions may be distributed within the UE according to implementation choice.
5GMS AF and 5GMS AS are Data Network (DN) functions and communicate with the UE via N6 as defined in TS 23.501.
Functions in trusted DNs, e.g. a 5GMS AF in the Trusted DN, are trusted by the operator's network as illustrated in Figure 4.2.3-5 of TS 23.501. Therefore, such AFs may directly communicate with the relevant 5G Core functions.
Functions in external DNs, e.g. a 5GMS AF in the External DN, may only communicate with 5G Core functions via the NEF using N33.
The present document specifies the according network architectures for 5GS. The 5GMS architecture may be applied to an EPS although such an application is not specified in the present document and is left to the discretion of deployments and implementations.
The 5G Media Services Architecture maps the overall high-level architecture shown in Figure 4.1.1-1 above to the general architecture shown in Figure 4.1.1-2 below.
The remainder of the present document specifies stage 2 aspects of the media streaming functional entities shown in the general architecture of Figure 4.1.1-2.
This architecture specification addresses two main scenarios as concerns each individual media streaming operation:
Downlink streaming: The network is the origin of the media and the UE acts as the consumption device.
Uplink streaming: The UE is the origin of the media and the network acts as the consumption entity.
The functional entities and interfaces of the media streaming general architecture need to be elaborated with specificities relating to downlink and uplink streaming. For this purpose, corresponding descriptions add the suffix "d" for downlink and "u" for uplink functionality as appropriate in each case.
Clause 4.2 introduces the 5G Unicast Downlink Media Streaming architecture.
Clause 4.3 introduces the 5G Unicast Uplink Media Streaming architecture.
This clause and subsequent subclauses of clause 4.1.2 define a generalized Media Delivery architecture of which the architecture for 5G Media Streaming (5GMS) defined elsewhere in the present document is one possible realisation. In case of any misalignment between the two, the 5GMS architecture has precedence over this generalised architecture.
Due to the similarity of the 5GMS architecture (as defined in the present document) to the architecture for Real-Time media Communication (RTC) defined in TS 26.506, the RTC functions and 5GMS functions may share or may make use of many common functionalities for both media session handling and media delivery. A generalized Media Delivery architecture that integrates 5GMS and RTC functionality in the 5G System is defined in Figure 4.1.2.1-1.
Media AS: An Application Server dedicated to Media Delivery.
Media Client: A UE internal function dedicated to Media Delivery comprising:
Media Session Handler: An entity on the UE that communicates with the Media AF in order to establish, control and support the delivery of a media session.
Media Access Function: An entity on the UE that communicates with the Media AS in order to access and deliver media content. The media access function for example may be further sub-divided into content delivery protocols, codecs, media types and metadata representation.
Media-aware Application: An application entity on the UE that makes use of 3GPP-defined APIs to invoke the Media Session Handler and/or the Media Access Function in order to support Media Delivery.
The following reference points are defined for Media Delivery:
M1:
Reference point between the Media Application Provider and the Media AF for the provisioning of Media Delivery.
M2:
Reference point between the Media Application Provider and the Media AS for the purposes of ingesting media into the Media AS or egesting media from the Media AS.
M3:
Reference point between the Media AF and the Media AS for the purposes of Media AS configuration and/or for media session handling in relation to Media Delivery.
M4:
Reference point between the Media AS and the Media Access Function in the UE for the purpose of downlink transport of media from the Media AS to the Media Access Function ("content distribution") or uplink transport of media from the Media Access Function to the Media AS ("content contribution").
M5:
Reference point between the Media AF and the Media Session Handler in the Media Client for the purpose of media session handling in relation to Media Delivery.
M6:
Reference point between the Media-aware Application and the Media Session Handler for the purpose of configuring the Media Session Handler.
M7:
Reference point between the Media-aware Application and the Media Access Function for the purpose of media access control.
M8:
Reference point between the Media-aware Application and the Media Application Provider.
M9:
Reference point between one instance of the Media AF and another for the purpose of Media AF instance chaining.
M10:
Reference point between one instance of the Media AS and another for the purpose of distributed service chaining of Media AS instances.
M11:
Reference point between the Media Session Handler and the Media Access Function (both in the Media Client) for the purpose of configuring the Media Session Handler and/or media access control.
M12:
Reference point between one Media Access Function and another for the purpose of peer-to-peer media transport between different Media Clients when this is permitted by the 5G System.
The Media AF exposes the following network service interfaces for media session handling:
Provisioning API (Maf_Provisioning): External API, exposed to the Media Application Provider by the Media AF at reference point M1 to provision the usage of the Media Delivery and to obtain feedback.
Media Session Handling API (Maf_SessionHandling) exposed by a Media AF to the Media Session Handler at reference point M5 and/or to the Media AS at reference point M3 for media session handling, control, reporting and assistance that also include appropriate security mechanisms, e.g. authorization and authentication.
The Media Session Handler exposes the following UE APIs for media session handling:
Media Session Handling Client API: exposed by the Media Session Handler to the Media-aware Application at reference point M6 and to the Media Access Function at reference point M11, for configuring media session handling, including service launch.
The Media AS exposes the following network service interfaces to support media transport:
Media Application Server Configuration API (Mas_Configuration) used by the Media AF at reference point M3 to configure the Media AS.
The Media AS exposes the following media transport interfaces:
Application Provider media transport interface between the Media AS and the Media Application Provider, used to exchange media data using a media transport protocol at reference point M2.
Client-facing media transport interface between the Media Access Function and the Media AS, used to exchange media data using a media transport protocol at reference point M4.
The Media Access Client exposes the following UE APIs for media access control:
Media Access Control API exposed by the Media Access Function to the Media-aware Application at reference point M7 and to the Media Session Handler at reference point M11, in order to configure and communicate with the Media Access Function.