# 3GPP TR 26.510 Change Request - Summary

## Document Information
- **CR Number**: 0006, Revision 6
- **Release**: Rel-20
- **Category**: B (addition of feature)
- **Work Item**: FS_Energy_Ph2_MED / AMD_PRO-MED
- **Source**: Orange
- **Meeting**: S4-260064 (S4#135, February 2026)

## Main Purpose
This CR proposes a solution for Key Issue #6 (Client-driven management of media delivery service energy optimisation) by adding a new clause 7.11 to TR 26.942. The solution enables Media Clients to select Media Entry Points based on energy characteristics using Common Media Server Data (CMSD).

## Key Technical Contributions

### 1. Solution Overview (Clause 7.11)
The CR introduces **Solution #10**: "Client-driven selection of Media Entry Point in the generalised Media Delivery System based on energy characteristics"

**Key Issue Mapping:**
- Addresses KI#1 (Energy-related Information exposure)
- Addresses KI#6 (Client-driven management of media delivery service energy optimisation)

### 2. Functional Description (7.11.2)

**Core Concept:**
- Leverages existing CMSD [CTA-5006] mechanisms to communicate energy consumption and CO₂ equivalent information from media servers to media players
- Enables media players to select distribution paths/modes with least environmental impact
- Integrates an **Energy Information Manager** in media content servers to collect energy data across the distribution chain
- Media players supplement server data with local UE energy consumption data

**User Modes:**
Three energy preference modes are defined:
- **Eco mode**: Prioritizes energy efficiency over QoE
- **Standard mode**: Balances energy efficiency and QoE
- **Performance mode**: Prioritizes QoE over energy consumption

**Reporting Mechanisms:**
- Uses CMSD for downlink energy information (server to client)
- Uses CMCD [CTA-5004] for uplink reporting (client to server/ASP)
- Custom key names employed for energy-specific parameters (not yet standardized in CMCD/CMSD)

**Scope Limitation:**
- Applicable only to downlink 5G Media Streaming (5GMS) context
- UE energy collection methods are out of 3GPP scope

### 3. Architecture Mapping (7.11.4)

**Reference Architecture:**
- Based on 5GMSd architecture (TS 26.501, TS 26.506)
- Reuses Solution #5 architecture for collecting/exposing energy characteristics
- **Key difference**: No Energy Information Collector in UE; Media Player receives energy data directly from 5GMSd AS via CMSD

**Key Components:**
- **Energy Information AF** (instantiated in 5GMSd AF):
  - Subscribes to NF Energy Information from EIF (per TS 23.501 clause 5.51)
  - Subscribes to AS Energy Information from 5GMSd AS
  - Exposes aggregated Network Energy Information to 5GMSd AS
  
- **Media Stream Handler**: Decision-making function that selects appropriate service location based on energy characteristics

**Reference Points Reused:**
M1d, M2d, M3d, E3, M4d, M5d, E5, M6d, M8, M11d, E12

### 4. Energy-Related Information (7.11.5)

**Relevant Granularities:**
- **Per media delivery session**: Aggregating energy from Application Data Flows with same IP 5-tuple or session identifier
- **Per service location**: Aggregating Media AS Energy Reports from all (Edge) Media AS instances exposing that service location

**Energy Information Types:**
- Energy consumed (in Joules per TS 29.122)
- Environmental cost of energy supply

**NF Energy Report (7.11.4.3):**
- Reported by EIF per TS 29.566 clause 6.1
- Uses Application ID initially; refined using Service Data Flow Descriptions during session
- Granularity as requested in subscription

**Media AS Energy Report (7.11.4.4):**
- Uses Application ID and Service Location identifier initially
- Fine-tuned using Service Data Flow Description during session
- Reports from multiple Service Locations provided to enable comparison

**CMSD Information (7.11.4.5):**
- Parameters defined for reporting energy information about service locations
- Transmitted at reference point M4d from 5GMSd AS to Media Player

### 5. Procedures (7.11.6)

**Key Procedure Steps (differences from baseline):**

**Step 2**: Media-aware Application indicates selected end-user energy mode when initiating media delivery session

**Step 4a**: 5GMSd AS subscribes to Network Energy Information from Energy Information AF (including Application ID and Service Location notification URLs)

**Step 6**: Media Session Handler obtains Service Access Information including Energy Information AF access details and CMCD configuration

**Step 10a/20a**: Energy Information AF exposes processed Network Energy Information about provisioned service locations to 5GMSd AS

**Step 15**: Media Session Handler provides Media Entry Points to Media-aware Application **including energy-related information for each**

**Step 16**: Media-aware Application selects Media Entry Point with energy characteristics matching configured energy mode

**Steps 16-19**: Integrated into media delivery session loop to enable **dynamic reselection** of Media Entry Point if characteristics change

**Note**: Modifying Media Entry Point during session may cause playback discontinuity

**Step 28a/28a bis**: 5GMSd AS includes Network Energy Information in HTTP headers of Media Entry Point response using CMSD

**Step 29/29bis**: Media Stream Handler selects Service Operation Point based on Network Energy Information received via CMSD

### 6. Gap Analysis (7.11.7)

**Identified Gaps in Rel-19 Specifications:**

1. Ability to provision use of CMSD by AS to report network energy information to UE (reference point E1/M1)
2. Ability for AS to subscribe to Network Energy Information from Energy Information AF via E3 (citing Application ID or Service Data Flows)
3. Ability for 5GMSd AF to provide CMCD configuration in Service Access Information via M5d
4. Ability for Media Session Handler to provide CMCD configuration to Media Stream Handler via M11d
5. Ability for Energy Information AF to expose Network Energy Report about service locations to AS
6. Ability for Media Stream Handler to process energy information from AS via M4
7. Ability for Media Stream Handler to expose Energy Information to 5GMSd-Aware Application via M7d
8. Ability for Media Stream Handler to send energy information to ASP via M8d using CMCD event mode with HTTP POST
9. Support for CMSD in 5GMS (under study outside this work scope)
10. Ability for Media Entry response to include Network Energy Information in CMSD HTTP headers
11. Ability for Media Stream Handler to extract CMSD energy information and use for Service Operation Point selection

### 7. Proposed Normative Changes

#### Stage 2 Changes (7.11.8.1)

**New Stage 2 Specification Scope:**
- Provisioning Energy Information AF via M1d
- Reporting energy information by 5GMSd AS via E3 with aggregations per:
  - Network slice
  - Data Network
  - Distribution Configuration (service location)
  - Application ID
  - Media streaming session
- Subscription/exposure of aggregated network energy information from Energy Information AF to 5GMSd AS

**TS 26.501 Changes:**
- Include Energy Management service subfunction in 5GMSd AS
- Document AS service location selection based on energy information transmitted via CMSD

#### Stage 3 Changes (7.11.8.2)

**New Stage 3 Specification Scope:**
- Provisioning Energy Information AF via M1d
- Reporting energy information by 5GMSd AS with specified aggregations
- Subscription/exposure APIs at E3

**TS 26.510 Changes:**
- Extend Content Hosting Configuration (clauses 5.2.8, 8.8.3.1) with Boolean flag in DistributionConfiguration indicating CMSD reporting eligibility

**TS 26.512 Changes:**
- Extensions to procedures/interfaces at M1d, E3, M4d, M6d, M8d for energy-related information
- Extensions to support energy information exposure using CMSD
- Extensions to support CMCD version 2 information

### 8. Summary and Benefits (7.11.9)

**Solution Advantages:**

1. **Reduced environmental impact**: CO₂ emissions consideration in Media Entry Point selection
2. **User transparency**: Environmental impact visibility without privacy concerns
3. **Flexibility**: Compatible with existing 5G System optimizations
4. **Customization**: User choice via energy optimization modes
5. **Global optimization**: Entire delivery chain considered (production, encoding, delivery, consumption)
6. **Minimal UE impact**: Leverages existing CMSD/CMCD mechanisms in streaming ecosystem
7. **No User Plane impact**: Energy reporting handled in control/management plane

**Applicability:**
- Any 5GMSd Application Provider delivering via 5GMSd System
- Natural integration with MPEG-DASH and HLS adaptive streaming architectures
- Supports French regulator (Arcom/Arcep) recommendations on environmental impact of audiovisual services

## References Added
- [CMSD]: CTA-5006 "Common Media Server Data"
- [CMCD]: CTA-5004 "Web Application Video Ecosystem – Common Media Client Data"
- [26512]: TS 26.512 "5G Media Streaming (5GMS); Protocols"