# 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