Markdown Version | Session Recording

Session Date/Time: 18 Dec 2024 14:00

GREEN

Summary

The GREEN Working Group held a meeting to primarily discuss and gain initial consensus on identified use cases for Energy Efficiency (EE) in networks. Emil presented a consolidated set of use cases, which were then discussed for clarity, scope alignment with the WG charter, and potential merging. A poll of those present was taken for each use case to gauge the sense of the room. The discussion also touched upon the approach for defining requirements and future meeting plans.

Key Discussion Points

• Agenda Review & Charter Scope: The chairs reiterated the Note Well, IPR, and Code of Conduct. The agenda prioritized use case discussion, with requirements as a secondary consideration. A crucial reminder was given on what is explicitly out of scope for GREEN, including routing protocols, impact on service quality, environmental sustainability (beyond energy), and carbon accounting. The focus remains on Energy Efficiency.
• Use Case Template: A proposed template for use cases was introduced, comprising a general description, aspects specific to the GREEN WG (e.g., components reporting on energy, reconfigurability), and a breakdown into requirements.
• Use Case 1: Incremental Application of the Green Framework:
  • Description: Focuses on migrating legacy network devices to support EE, exemplified by optimizing old routers or replacing line cards.
  • Discussion: Emphasized the importance of establishing a baseline for energy usage to measure improvements. The sense of those present indicated this use case is well-understood and within scope.
• Use Case 2: Selective Reduction of Energy Consumption:
  • Description: Aims to adjust network power consumption proportionally to traffic patterns (e.g., daily peaks/valleys) using mechanisms like sleep modes or component deactivation.
  • Discussion: Questions arose regarding the granularity of control (simple on/off vs. multiple power states) and whether control applies at the component, device, or network level. The sense of those present was that this use case is clear and within scope.
• Use Case 3: Reporting on Life Cycle Management:
  • Description: Involves tracking embedded carbon from manufacturing, transport, and recyclability, correlating operational location with carbon factors and observing the energy mix.
  • Discussion: There was strong sentiment that this use case, while important, falls out of scope for the initial GREEN WG charter, which focuses on operational Energy Efficiency rather than broader environmental sustainability or carbon accounting. It was suggested for a "living list" or a separate document for future consideration.
• Use Case 4: Real-time Energy Metering of Virtualized/Cloud-Native Network Functions:
  • Description: Aims for precise, real-time estimation of energy consumed by virtualized or cloud-native network functions (VNFs/CNFs), adapting to dynamic environments like containers.
  • Discussion: Concerns were raised about the specific meaning of "real-time" and the challenges of measuring energy for short-lived, dynamic entities (e.g., containers). Further discussion is needed to clarify the scope and specifics of this use case.
• Use Case 5: Indirect Energy Monitoring and Control (including PoE/Smart PDUs):
  • Description: Addresses scenarios where a device reports on or controls the energy consumption of other entities, such as Power over Ethernet (PoE) switches powering access points, or smart Power Distribution Units (PDUs) monitoring servers. A key requirement is avoiding double accounting of power.
  • Discussion: This was identified as a key use case with significant implications for modeling and control. The sense of those present was that this is an important area but requires further detailed discussion due to its complexity and implications.
• Use Case 6: Consideration of Other Domain for N-to-N Metrics (Aggregated Metrics):
  • Description: Focuses on enabling end-to-end (N-to-N) Energy Efficiency metrics by combining or composing metrics from various domains (e.g., 3GPP, network slices).
  • Discussion: While full N-to-N might be too broad, the concept of aggregating and composing metrics from different sources (e.g., for a network segment or service slice) was considered in scope. It was suggested to be a potentially lower priority initially due to complexity, focusing on simplicity first. The title might be refined to "Aggregated Metrics."
• Use Case 7: Dynamic Adjustment of Network Elements Throughput in Wireless Transport Networks:
  • Description: Adjustment of radio link power based on observed traffic levels.
  • Discussion: This was broadly identified as a specific example or instance of Use Case 2 (Selective Reduction of Energy Consumption) and should be merged.
• Use Case 8: Video Streaming:
  • Description: Addresses energy consumption due to the growth of simultaneous, high-bitrate video flows, leading to larger differences between peak and valley traffic. It proposed metrics at the per-stream level.
  • Discussion: This was also largely seen as an instance of Use Case 2. However, the proposal for "per-flow energy" metrics was highlighted as being out of scope for the current charter. The sense of those present indicated that this use case as a distinct entity, especially with per-flow aspects, is not within the initial scope.
• Additional Use Cases Presented (merged during discussion):
  • Access Point Energy Saving: Detailed power management for Wi-Fi Access Points, often PoE-powered, with modes like power-off, hibernation, and low-power consumption with selective band activation. This was deemed a specific example of Use Case 5 (Indirect Energy Monitoring and Control) and should be merged.
  • Fixed Network Energy Saving: Described calendar-based or traffic-load-driven energy saving in fixed networks by shutting down/sleeping devices or adjusting interface speeds, processor cores, and clock speeds. This was seen as a specific example of Use Case 2 (Selective Reduction of Energy Consumption) and should be merged.
  • Energy Efficiency Network Management: Focuses on operators seeing real-time consumption, identifying energy-saving opportunities, and tracking trends across the entire network, using metrics and composite metrics. This was considered broadly in scope but may need further refinement.

Decisions and Action Items

Decisions Made:

1. Use Case 1 (Incremental Application of the Green Framework): Is well understood and within scope for initial GREEN WG work.
2. Use Case 2 (Selective Reduction of Energy Consumption): Is well understood and within scope for initial GREEN WG work.
3. Use Case 3 (Reporting on Life Cycle Management): Is considered out of scope for the initial GREEN WG work. It will be tracked on a "living list" for future consideration.
4. Use Case 7 (Dynamic Adjustment of Network Elements Throughput in Wireless Transport Networks): Will be merged as a specific example/sub-case of Use Case 2.
5. Use Case 8 (Video Streaming): As a distinct use case, particularly with its "per-flow energy" aspects, is considered out of scope for initial GREEN WG work.
6. Access Point Energy Saving (Unnamed): Will be merged as a specific example/sub-case of Use Case 5.
7. Fixed Network Energy Saving (Unnamed): Will be merged as a specific example/sub-case of Use Case 2.

Use Cases Requiring Further Discussion:

• Use Case 4 (Real-time Energy Metering of Virtualized/Cloud-Native Network Functions): Requires further clarification on its scope and specifics.
• Use Case 5 (Indirect Energy Monitoring and Control): Is a key use case but needs more detailed discussion on its scope, complexity, and implications for initial work.
• Use Case 6 (Consideration of Other Domain for N-to-N Metrics): The concept of aggregated/composable metrics is in scope, but "end-to-end" may need refinement, and it may be a lower initial priority.
• Energy Efficiency Network Management (Unnamed, now Use Case Z): Is broadly in scope but may need further refinement.

Action Items:

• Chairs: Discuss the strategy for documentation, potentially splitting use cases into a separate document for earlier adoption to consolidate consensus, with requirements to follow.
• Diego: Share the draft Liaison Statement (LS) on the mailing list for review and input, including clarification on its formal origin (chairs, WG, or IETF).
• Chairs: Confirm the outcome of the use case discussion and polls on the mailing list to ensure broad consensus, in line with IETF practices.
• Chairs: Schedule future interim meetings, aiming for staggered times (e.g., 8 hours apart) to accommodate geographically dispersed participants, likely in late January/early February.

Next Steps

• Mailing List Confirmation: The outcomes of the use case discussions and polls from this meeting will be posted to the GREEN WG mailing list to gather broader input and confirm consensus.
• Document Strategy: The chairs will further discuss the proposal to advance the use cases into a Working Group Document first, potentially separating the detailed requirements for a later stage or separate document.
• Future Interims: The chairs plan to schedule additional interim meetings in late January or early February to continue work on requirements and other topics. These will be scheduled at varying times to accommodate global participation.
• Liaison Statement: The draft LS will be circulated on the list, and once consensus is reached, it will be formally issued to foster collaboration with other relevant organizations.