GREEN

Summary

The GREEN Working Group (WG) held a two-hour session at IETF 125. The Chairs (Diego Lopez and Rob Wilton) noted the successful adoption of the three base documents: [draft-ietf-green-terminology], [draft-ietf-green-use-cases], and [draft-ietf-green-framework]. The group has transitioned to a bi-weekly "lightweight design team" meeting structure, which is open to the whole community, to accelerate the development of these base documents and the core YANG data model.

The session focused on aligning the base framework with the evolving [GREEN Power and Energy YANG data model]. A significant portion of the meeting was dedicated to an open discussion on whether the initial YANG model should include configuration capabilities (power state control) or remain focused on operational telemetry. There was a general sense of the room to proceed with a simple configuration leaf to avoid delaying the model’s maturity.

Key Discussion Points

Working Group Status and Core Documents

Chair Introduction: Diego Lopez and Rob Wilton highlighted that the WG aims to be the core reference for energy measurement and control within the IETF to avoid fragmentation. Bi-weekly interim meetings will continue on Thursdays to finalize the core documents.
Terminology for Energy Efficiency Network Management: Qin Wu presented [draft-ietf-green-terminology] (v01). New terms "Energy Object" and "Energy Saving" were added. Benoit Claise suggested keeping the document open for alignment until the other base documents are ready for publication.
IETF125 use cases draft 01 slices: Emile Stephan presented [draft-ietf-green-use-cases]. A new use case (UC 16) regarding network-level cross-layer energy saving was added. A hackathon in Vienna is planned to improve consistency between use cases and the framework.
Framework for Energy Efficiency Management: Marisol Palmero presented [draft-ietf-green-framework]. Discussion focused on the data collection architecture and the relationship between device-centric and controller-centric models.

Base YANG Model and Open Discussion

GREEN Power and Energy YANG data model: Qin-Chen presented the current state of the model. It defines identities for energy objects, power/energy attributes, accuracy classifications, and relationships (e.g., poweredBy, meteredBy).
Open Discussion on Base Documents and Model: Benoit Claise led a discussion on configuration vs. operational data.
- Power States: Tony Li questioned how to turn components off and express functional dependencies. Benoit Claise presented two options: (1) Wait for a complex network-wide intent model, or (2) Include a simple read/write power-state leaf using identityref to support existing sets (IEEE/EMAN) or a 0-100 scale.
- Measurement Interval: Tony Li emphasized the importance of knowing how often a device measures a value, distinct from how often it is streamed via telemetry.
- Sense of the Room: Participants (including Carsten Rossenhövel and Rob Wilton) generally supported "Option 2"—adding a simple configuration mechanism now to show progress, rather than waiting for a perfect network-wide intent solution.

Additional Proposals

Path Energy Traffic Ratio API (PETRA): Luis Contreras presented an update on the PETRA API, aiming to provide visibility into energy consumption along a specific network path. The authors intend to request adoption once core documents stabilize.
Export of Energy Consumption Information in IPFIX: Jing-Jie Yan proposed using IPFIX for traffic-correlated energy telemetry. Diego Lopez and Benoit Claise advised aligning the Information Elements (IEs) with the units and object contexts defined in the GREEN core model to ensure consistency.
Chen-Hybrid Energy Saving Mechanism for Transport Network: Xinyu Chen presented a mechanism combining local (device-centric) fast response with global (controller-centric) strategic optimization. Rob Wilton suggested providing feedback to the framework authors to see how this fits into the general architecture.
Functional entities for enabling per service eco-data reporting: Luis Contreras introduced functional blocks for attributing energy consumption to specific connectivity services. This work was moved from the IRTF SUSTAIN RG to GREEN as it focuses on engineering and reporting rather than pure research.

Decisions and Action Items

YANG Model Direction: The WG will pursue "Option 2" for the base YANG model, incorporating a simple identityref-based configuration for power states to enable component control while focusing primarily on operational data.
GitHub Migration: Draft repositories for terminology and use cases will be moved to the official GREEN WG GitHub organization to improve tracking (Action: Chairs/Authors).
Model Alignment: The authors of the IPFIX and PETRA proposals are tasked with aligning their data types and units with the base [GREEN Power and Energy YANG data model] (Action: Jing-Jie Yan, Luis Contreras).

Next Steps

Bi-weekly Interims: Resume on March 30th at 2:00 PM UK time to continue refining core drafts.
Call for Adoption: The [GREEN Power and Energy YANG data model] is expected to move toward a call for adoption soon, pending the inclusion of the agreed-upon configuration leaves.
IETF 126 Preparation: A hackathon activity is being considered for Vienna to further align use cases with the framework and model.

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