A.1 End-to-end model

26.5123GPP5G Media Streaming (5GMS)ProtocolsRelease 17TS

Figure A.1‑1 below depicts an end-to-end model for the 5GMS parameter propagation for DASH streaming with dynamic policy. The arrows indicate the main information flow. The interfaces specified in TS 26.501 [2] are used throughout. However, there are additional interfaces (i.e. P1 or U1), which are not in the 5GMS Architecture.

Figure A.1‑1: End-to-end model for dynamic policy parameter propagation

The interfaces involved and their roles in this feature are as follows:

– M1: Provisioning interface between the 5GMS Application Provider and the 5GMS AF.

– P1: The 5GMS Application Provider provisions the DASH MPD generator, e.g. by annotating the MPD with Service Descriptions.

– U1: User Interface to the 5GMS-Aware Application.

NOTE: The 5GMS Application Provider controls the application, i.e. controls the GUI choices.

– M8: Non-standardized input from the 5GMS Application Provider to the 5GMS-Aware Application, such as country-specific application behaviours (languages, on-demand catalogue, etc).

– Input on subscriptions (e.g. 4K subscription versus SD subscription).

– Device-specific content selection rules (e.g. SmartPhone versus Smart TV).

– Additional service offering features (e.g. background download possible).

– C1 (one of M6 or M7): Information from the 5GMS-Aware Application to the 5GMS Client, e.g. user content selections.

– M6: Information flow from the DASH Player to the Media Session Handler.

– M7: Information flow from the Media Session Handler to the DASH Player.

– M5_1: Information flow into the Media Session Handler for parameter provisioning (Policy Descriptions, which originate from 5GMS AF and 5GMS Application Provider). The Policy Descriptions contain or reference the detailed Service Access Information, i.e. URLs to activate a certain policy.

– M5_2: Information flow from the Media Session Handler to the 5GMS AF. This includes:

– input to create the Service Data Flow Templates (see TS 23.503 [33]) for identifying the application data flows within a PDU Session,

– an identifier for the Dynamic Policy instance (e.g. QoS, Conditional Zero-rating, charging, etc) and

– optionally, Network Assistance information, e.g. bit rate recommendations.

In its Annex K, the DASH standard [32] specifies so-called "Service Descriptions". The purpose of Service Descriptions is to provide additional information to a DASH player to influence its "Selection Logic", e.g. a DASH player should prefer a certain set of representations within an adaptation set. It is assumed in the following that the DASH MPD can be annotated using Service Descriptions to give hints for subscription models and different device types.

The 5G System specifies a number of different means to detect application flows. When activating a Dynamic Policy, the Media Session Handler provides a Service Data Flow Template to the 5GMS System, which identifies the application flow(s) of interest. It is assumed here that multiple applications are executing simultaneously on a given UE and that each application may independently access the network. Therefore, the Media Session Handler needs to provide (and update) these Service Data Flow Templates in order that the application traffic can be treated according to the corresponding Dynamic Policy.

In the following clauses, the parameter propagation for a number of different use cases is described.