Summary of S4-260061: Considerations on Work Topic 1 - Media Delivery Architecture

Document Overview

This contribution from Qualcomm provides initial considerations and structure for Work Topic #1 (Media Delivery Architecture) in the FS_6G_MED study item. The document proposes text for TR 26.870 v0.0.1, establishing the foundation for studying media delivery architecture aspects for 6G systems.

Main Technical Contributions

1. High-Level Description and Scope

The contribution establishes that the work topic will study a harmonized media delivery architecture for 6G based on:
- TS 26.501 (5G Media Streaming architecture)
- TS 26.506 (5G Real-time Media Communication Architecture)
- New 6G architecture developments from TR 23.801-01

Key aspects to be studied include:
- Assessment of whether current 5G media delivery architecture functionalities accommodate new 6G use cases
- Identification of reusable and improvable components from 5G and earlier generations
- Architecture simplification for improved deployability and implementability
- Further harmonization of media delivery architecture for streaming and conversational services
- Collection and enablement of relevant existing and emerging content delivery protocols in 6G
- Alignment with SA2's 6G design concepts
- Accommodation of commercially relevant media services and evolving standardization activities

2. Dependencies and Context

Relevant SA2 Key Issues from TR 23.801-01:
- Key Issue #2: SBA framework
- Key Issue #3: Support of Network Slicing in the 6G system
- Key Issue #4: User Plane Architecture
- Key Issue #5: QoS Framework for 6G
- Key Issue #7: Network Exposure
- Key Issue #17: Migration and Interworking

External coordination needed with:
- SA1 (use cases and requirements - TR 22.870)
- SA2 (architecture - TR 23.801-01)
- RAN (TR 38.960)
- External organizations: SVTA, CTA WAVE, ISO/IEC JTC1 SC 29, 5G-MAG, Metaverse Standards Forum, Khronos, IETF

3. Media Application Service Models

The contribution proposes documenting several conceptual models to define how applications can benefit from the media delivery architecture:

3.1 Generalized Media Application Service Model

Defines an 8-point model describing:
- Service Data Flows traversing the User Plane between Media Client and Media AS at reference point M4
- Support for bidirectional media content flow
- Multiplexing of Application Data Flows onto Service Data Flows
- Different service location endpoints during a session
- Mapping to different deployed servers (physical or virtual)
- Mapping to one or multiple physical network interfaces based on ANDSP/URSP
- Traversal of different Data Networks and Access Networks
- Service Data Flow migration due to mobility

3.2 Downlink Media Streaming Application Service Model

Provides a structured table defining:
- AS instance: An AS instance in the Media Delivery System deployment
- Content Hosting Configuration: Corresponding to a single Provisioning Session in the AF
- Distribution Configuration: Modeling a service location exposed by the AS instance
- Downlink media streaming session: Modeling a session that may span multiple content items
- Service Data Flow: An HTTP connection at reference point M4d (IP 5-tuple)
- Application Data Flow: Series of media segment download requests, with support for multiplexing multiple HTTP requests on the same connection (e.g., different DASH Adaptation Sets on HTTP/3)

3.3 Uplink Media Streaming Application Service Model

Provides similar structured table for uplink with:
- 5GMSu AS instance: Edge AS instance in the 5GMS System deployment
- Content Publishing Configuration: Corresponding to a Provisioning Session in the 5GMSu AF
- Contribution Configuration: Modeling a service location exposed by the AS instance
- Uplink media streaming session: Modeling a session that may span multiple content items
- Service Data Flow: HTTP connection at reference point M4u (IP 5-tuple)
- Application Data Flow: Series of media segment upload requests with multiplexing support

Key technical details:
- Finest granularity visible to 5GMS AS is the Service Data Flow (HTTP connection)
- Service Data Flows associated with sessions via media delivery session identifier in HTTP request headers (per TS 26.512 clause 6.2.3.6)
- Service location (HTTP authority and URL path) enables association with Distribution/Contribution Configuration

3.4 Real-time Communication Application Service Model

Placeholder for future completion.

4. Key Issues Identified

Two initial key issues are identified for study:

1. Should the media delivery architecture for streaming and real-time communication services be harmonized or separated?

2. What relevant existing and emerging content delivery protocols would map to the 5G media delivery architecture, and what extensions or simplifications can be done for 6G Media Delivery?

5. References

The contribution adds relevant normative and informative references including:
- TR 22.870 (SA1 6G use cases)
- TR 23.801-01 (SA2 6G architecture)
- TS 26.501, 26.506 (5G media delivery architectures)
- Multiple TS 26.5xx series specifications
- Placeholder for TS 22.ABC (6G System Requirements)

Editorial Notes

The document includes several editor's notes indicating areas requiring future work:
- Completion of potentially relevant use cases and requirements from SA1
- Possible addition of more application models
- Completion of real-time communication application service model
- Addition of more key issues