Streaming in the context of this specification is defined as the delivery of time-continuous media as the predominant media. Streaming points to the fact that the media is predominantly sent only in a single direction and consumed as it is received. Additionally, the media content may be streamed as it is produced, referred to as live streaming. If content is streamed that is already produced, it is referred to as on-demand streaming.
The overall 5G Media Streaming Architecture is shown in Figure 4.1-1 below.
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 represents the specified 5GMS functions within the 5G System (5GS) as defined in TS 23.501. Three main functions are defined:
5GMS AS: An Application Server dedicated to 5G Media Streaming.
5GMS Client: A UE internal function dedicated to 5G Media Streaming.
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, i.e. 5GMS AFs in the external DNs, are trusted by the operator's network as illustrated in Figure 4.2.3-5 of TS 23.501. Therefore, AFs in trusted DNs may directly communicate with relevant 5G Core functions.
Functions in external DNs 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 above to the general architecture shown in Figure 4.1-2 below.
The remainder of the present document specifies stage 2 aspects of the media streaming functional entities shown in the general architecture of Figure 4.1-2.
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.