Session Date/Time: 19 May 2025 14:00

GREEN

Summary

The GREEN Working Group held a two-hour interim meeting focused on progressing the Use Cases, Framework, and Terminology documents. Discussion on the Use Cases document centered on updating its structure to highlight "green" aspects and soliciting more reviews for adoption. A detailed presentation on the energy efficiency management framework elicited broad agreement on its importance, particularly for network-level models, and a consensus to progress framework and data model development in parallel. For terminology, the working group indicated a preference for one of the two existing drafts as a potential starting point, emphasizing the need for a focused set of terms directly relevant to the charter. Key action items include document updates, extensive mailing list discussion, and a next interim meeting dedicated to data models.

Key Discussion Points

1. Use Cases Document

Goal: The chairs reiterated the goal of achieving working group adoption for the use cases document, emphasizing the need for consensus around the defined use cases.
Previous Status: An adoption poll prior to IETF 122 lacked sufficient support and reviews, with a noted need for editorial cleanup.
Proposed Structure: Carlos Bernardos suggested a homogeneous structure for use cases, including a general description, aspects specific to GREEN, and potentially requirements. While the chairs (Rob, Diego) were cautious about formal "requirements," there was agreement on the value of a consistent structure and clear identification of "green" aspects.
Author Commitment: Carlos (co-author) supported a homogeneous structure and, while acknowledging time constraints, Marisol (co-author) confirmed the authors' willingness to update the document.
Clarification: Jensen suggested clarifying the scope of use cases like "fixed network" (e.g., routers, transmission equipment).
Timeline & Review: The chairs requested an update to the document within 2-3 weeks to allow for working group review before IETF 123, with the aim of conducting another adoption poll.
Mailing List: Participants were encouraged to send comments to the mailing list to foster discussion and drive progress.

2. Framework for Energy Efficiency Management

Presentation: Benoît presented the latest revisions of the framework document, addressing questions posed by the chairs.
Rationale for Framework:
- Necessity: The framework is distinct from general network management due to specific challenges in energy management, such as avoiding double-counting of power consumption and managing complex control relationships.
- Timeliness: It is considered critical to discuss the framework now as it impacts terminology and the structure of YANG models.
- Impact on YANG Models: The framework introduces concepts like "metering relationship" and "power source relationship" that are crucial for accurately representing energy flows and control mechanisms, especially when dealing with legacy devices, physical meters, and Power over Ethernet (PoE) scenarios.
Key Concepts Introduced:
- Energy Objects: Devices or components that consume or provide energy.
- Power Interfaces: Definitions for "power inlet" and "power outlet."
- Metering Relationship: To track which energy object is being monitored by a specific meter, crucial for avoiding double-counting.
- Power Source Relationship: To identify which energy object is sourcing power to another, important for understanding control dependencies.
Examples: Illustrations using basic power supplies, legacy devices with physical meters, new controllable devices, and PoE scenarios highlighted the need for these relationships.
Relationship to Physical Topology: The framework proposes that "power source" and "control" topologies are needed in addition to the physical topology to accurately manage energy efficiency.
Handling Static/Inaccurate Values: Yan clarified that the framework allows for plugging in data sheet values, and transparency in reporting how data is counted (e.g., as a constant value) is key.
Parallel Development: Rob suggested that framework development and data model development could proceed in parallel, with the former helping to refine the latter.
Community Involvement: Authors confirmed that the GitHub repository and regular calls are open to all interested participants.

3. Terminology Discussion

Existing Drafts: Rob presented a summary of two existing terminology drafts: draft-ietf-green-pipt-green-terminology and draft-blcp-green-terminology.
Comparison:
- draft-pipt: Defines ~40 terms, but some related to general environmental/CO2 aspects were questioned as being outside the GREEN WG charter. Energy/power terms were deemed comprehensive.
- draft-blcp: Defines ~15 terms (updated from 12), with some energy terms derived from RFC 7326 but potentially modified (requiring clarification). Efficiency terms were seen as useful.
Metrics: Carlos's slides suggested that metrics/measurement methods might be out of scope for terminology documents, but the chairs noted that the integration of metrics into terminology or YANG models is still an open question.
Carlos's Proposal: To create a new combined draft, merge authors, and appoint two editors.
Feedback on draft-pipt: A poll indicated mixed views, with some participants expressing concern that many terms might be outside the working group's direct scope. Tony Lee suggested defining terms only as they are needed for the data models.
Feedback on draft-blcp: A poll indicated stronger support for this draft containing useful terms as a potential starting point.
"Energy Efficiency Network Management" Term: Rob raised a concern that this term could be misconstrued to mean efficient management of networks, rather than management for energy efficiency.
Mailing List Focus: The chairs emphasized the need for further discussion on the mailing list to decide on a base draft and approach for consolidation.

Decisions and Action Items

Decision: The working group indicated a strong consensus that a framework for energy efficiency management is important.
Decision: There was strong consensus that a framework would impact the design of controller and network-level YANG models.
Decision: There was strong consensus that YANG models (at any level) and the framework document can be worked on in parallel.
Action Item: Authors of the Use Cases document (draft-ietf-green-usecases) are to update the document with a homogeneous structure (potentially incorporating a "what is green about this use case" section) and address scope clarifications. Target an update in 2-3 weeks for working group review before IETF 123.
Action Item: Framework document authors (draft-ietf-green-framework) are to continue refining the document based on discussion, particularly clarifying concepts like metering and power source relationships.
Action Item: Chairs to drive discussion on the mailing list regarding the terminology drafts:
- Which existing draft should serve as a base?
- How to combine efforts and authors?
- Clarify usage of terms from RFC 7326.
- Focus on a concise set of terms directly within the WG charter.
Action Item: All working group participants are encouraged to actively review existing drafts (Use Cases, Framework, Terminology, Data Models) and contribute comments to the mailing list.

Next Steps

Next Interim Meeting: Scheduled for Monday, June 16th, focusing primarily on data models. Time will also be allocated for updates on the framework and terminology documents.
IETF 123 (July): Two 1.5-hour slots have been requested. The goal is to move documents towards adoption.
Future Interims: Planned to occur between plenary meetings (1-3 interims), likely maintaining the current time slot (third Monday of the month).
Mailing List: The chairs strongly encouraged more discussion and reviews on the GREEN mailing list to accelerate progress and build consensus.
Design Team: The chairs are still considering whether a focused design team would be helpful for certain work items.