



Network Working Group                                  C. Pignataro, Ed.
Internet-Draft                                      Blue Fern Consulting
Intended status: Best Current Practice                         A. Rezaki
Expires: 14 May 2026                                               Nokia
                                                                J. Arkko
                                                                Ericsson
                                                                A. Clemm
                                                               Futurewei
                                                            H. ElBakoury
                                                  Independent Consultant
                                                               S. Prabhu
                                                                   Nokia
                                                        10 November 2025


Sustainability Considerations for Networking Protocols and Applications
            draft-pignataro-enviro-sustainability-consid-03

Abstract

   Embedding sustainability considerations at the design of new
   protocols and extensions is more effective than attempting to do so
   after-the-fact.  Consequently, this document also gives network,
   protocol, and application designers and implementers sustainability-
   related advice and guidance.

   This document recommends to authors and reviewers the inclusion of a
   Sustainability Considerations section in IETF Internet-Drafts and
   RFCs.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 14 May 2026.





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Copyright Notice

   Copyright (c) 2025 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
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   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Implications to the IETF  . . . . . . . . . . . . . . . . . .   3
   3.  Sustainability Guidelines for Protocol and Network Designers
           and Implementers  . . . . . . . . . . . . . . . . . . . .   3
   4.  Conclusion  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     4.1.  Call to Action  . . . . . . . . . . . . . . . . . . . . .   7
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   9
   8.  Informative References  . . . . . . . . . . . . . . . . . . .   9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9

1.  Introduction

   The ultimate objective of this document is to detail guidance
   regarding aspects of sustainability and environmental impact that
   authors and reviewers of Internet protocol and architecture documents
   should consider in a "Sustainability Considerations" section.

1.1.  Terminology

   This document leverages the terminology and concepts defined in
   [I-D.pignataro-green-enviro-sust-terminology], and readers are
   expected to be familiar with those.  Specifically, Section 3.1.1 of
   [I-D.pignataro-green-enviro-sust-terminology] describes concepts of
   particular relevance to this draft.








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2.  Implications to the IETF

   This section describes the implications of sustainability to the
   IETF.  Specifically, the high-level relevant areas on which the IETF
   can act, and a rough prioritization.  These potentially include use
   cases, protocols, metrics, etc.

   A key area to understand the relevance and implication is regarding
   IETF Protocols.

3.  Sustainability Guidelines for Protocol and Network Designers and
    Implementers

   This section renders the Sustainability Considerations into specific
   guidelines and advice for the design and development of networking
   technologies.

   These specific items are labeled so as to follow and reference as a
   check-list.

   a.  General:
       The section title "Sustainability Considerations" should be used
       to detail the environmental-impact implications of protocols,
       architectures, and Internet technologies.

       a.1.  For each of the items covered, explicitly state the
             "boundary of analysis" considered.  For example, this can
             include a scope, time boundary, or lifecycle phases.

       a.2.  Consider attributional versus consequential analysis
             methods, explaining environmental impact benefits.

       a.3.  Clearly state the units used for each magnitude in every
             analysis (e.g., gCO2e/kWh.)

   b.  Network Management:
       Several areas of network management have direct relationship with
       sustainability.

       b.1.  Metrics:
             Instrument equipment, network elements, and networks with a
             set of relevant and meaningful metrics that provide
             visibility into sustainability and environmental-impact
             attributes (e.g., power and energy consumption.)  This is
             the foundation for any mechanisms to improve and optimize
             sustainability.





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       b.2.  Managed Elements:
             Facilitate, extend, and enrich the manageability of network
             elements and sub-elements which have an environmental
             impact, such as Power Supplies.  For example, provide
             visibility into sourced power, e.g. energy mix, and allow
             to account for the "dirtiness" of power being consumed to
             obtain a truer picture of sustainability than can be gained
             by visibility into power consumption alone.

       b.3.  Automation and Policy Enforcement:
             Network management systems should evolve from being passive
             observers of sustainability metrics to actively enforcing
             sustainability-oriented policies.  Once energy consumption,
             carbon intensity, and other environmental data are exposed,
             automated systems should be empowered to make real-time
             adjustments aligned with operator-defined sustainability
             goals.  For example, network orchestrators could
             dynamically shift workloads or traffic away from
             infrastructure currently powered by high-carbon sources, or
             initiate graceful scaling down of non-critical services
             during periods of high energy demand.  Similarly, protocols
             and management frameworks could support scheduled
             downtimes, power state transitions, or routing policy
             adaptations based on thresholds related to energy
             efficiency, carbon emissions, or resource usage.  Embedding
             such automation capabilities ensures that sustainability is
             not merely a reporting layer, but a live operational
             dimension that can be acted upon in-network, in alignment
             with business or regulatory objectives.

   c.  Energy Management:
       Minimizing energy consumption is a critical consideration in
       making networks more sustainable.  Minimizing energy consumption
       typically comes also with important economic side benefits
       associated with reducing operational expenses and making network
       providers more competitive.

       To facilitate energy efficiency schemes, designers of networking
       devices and protocols should examine and consider the following
       considerations:

       c.1.  Energy linearity.  In many cases, the amount of power drawn
             by a device is not in linear proportion to the volume of
             traffic that is passed.  Instead, energy consumption when
             idle generally accounts for a very significant percentage
             of the energy consumption when under full load.  The
             implication of this is that the volume of traffic by itself
             is of relative consequence to energy consumption, as long



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             as the volume does not get to the point where additional
             equipment needs to be added to the network to handle peak
             loads.

       c.2.  Power saving modes.  Similarly, many devices and resources
             support power saving modes that can be entered when idled.
             Similarly, during periods of exceedingly low traffic, some
             links may support downspeeding associated with energy
             savings.  As a result, a big opportunity for energy savings
             involves schemes in which resources are temporarily put
             into power saving modes, including almost shut-down, at
             times when they are not needed.

       c.3.  Chattiness of protocols.  For a given protocol, what are
             the message exchange patterns? does the protocol rely on
             periodic updates or heartbeat messages?  Could such message
             patterns result in preventing links or nodes from going to
             sleep (absent other communications), and in such a case,
             would an alternative pattern be feasible?

       c.4.  Exploiting burstiness versus smoothening of traffic.  Is it
             feasible to design the protocol to transmit with a smoother
             traffic pattern with lower traffic volumes that are sent
             continuously, as opposed to a way that traffic is bulked up
             and then sent in one fell swoop?

       c.5.  Rapid discovery and convergence.  Does the protocol involve
             the exchange of state and information about other systems?
             In that case, how can the protocol be designed in such that
             any such information can be discovered quickly and protocol
             synchronization reconverged efficiently?  Does the protocol
             design support stateful schemes that might accelerate this?
             In cases where there is a possibility of nodes going to
             sleep, the associated overhead of going offline and coming
             back online should be minimized.  By shortening the time
             interval needed to go offline and come back online, it
             might be possible to enter sleep mode in situations where
             it would otherwise not be feasible.

       c.6.  Encoding schemes.  How much computational effort goes into
             encoding and decoding?  Assess the tradeoff between
             encoding efficiency and computational effort, which directs
             into carbon for cycles to perform coding operations.

   d.  Carbon Awareness:






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       d.1.  Consider Carbon Intensity (CI) / Emission Factor (EF) as an
             attribute.  For example, CI is used to optimize for lower-
             carbon sources of electrical energy (e.g., using
             renewables.)  Prioritizing electricity use when carbon
             intensity is low is a target, and, for that, this attribute
             needs to be accessed or advertised.

       d.2.  Consider embodied emissions (i.e., embedded carbon) with
             any new product.  For example, a new generation of
             networking device might significantly improve energy
             efficiency, and a replacement migration would include the
             embedded emissions (of producing and transporting the new
             product as well as disposing of the old one), and hence
             there's a break-even point (BEP).

   e.  Beyond Carbon:
       Characterize and note full-spectrum environmental impacts, beyond
       GHG emissions, and into water usage, raw materials usage,
       circularity in supply chain, repurpose, reuse, and recycle, etc.

       e.1.  Resource Awareness and Reporting.  Beyond greenhouse gas
             emissions, protocols should consider enabling awareness of
             other environmental resources such as water and raw
             materials.  For example, data centers may vary
             significantly in their water usage for cooling, depending
             on location, infrastructure, and workload.  Protocols can
             support sustainability by exposing or integrating with
             telemetry systems that report such metrics.  This allows
             higher-layer systems and orchestration frameworks to make
             deployment decisions that are sensitive to environmental
             constraints, such as avoiding water-intensive
             infrastructure during drought conditions or favoring
             resource-efficient sites for long-running tasks.
             Furthermore, protocols can provide policy hooks or
             signaling interfaces that allow operators to incorporate
             environmental metrics beyond carbon, into routing, load
             balancing, and service placement decisions.  While the
             protocols themselves may not directly control hardware or
             facility resource consumption, they can facilitate the
             collection and application of such insights in
             sustainability-aware operations.

       e.2.  Lifecycle Impact and Circularity.  Sustainability also
             requires a full-lifecycle perspective, considering how
             protocol design may influence the longevity, reuse, and
             recyclability of devices and systems.  Protocols that
             prioritize backward compatibility, modularity, and support
             for older hardware can extend the operational lifespan of



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             network infrastructure, reducing the frequency of hardware
             refreshes and thereby limiting e-waste.  In contrast,
             designs that require frequent upgrades or discard older
             technologies prematurely may contribute to unsustainable
             hardware churn.  Protocols can also enable lifecycle
             tracking through telemetry that helps estimate remaining
             useful life or suitability for repurposing.  By
             accommodating long-lived devices, especially those in
             constrained or remote environments, protocols can promote
             the principles of a circular economy where systems are
             designed to be reused, repaired, and recycled rather than
             discarded.  Such considerations are particularly important
             as the scale of Internet-connected devices continues to
             grow, bringing with it a corresponding increase in material
             and environmental impact.

4.  Conclusion

   The pre-eminent message in this document is to elevate the need and
   sense of urgency of including sustainability considerations in our
   protocol and system design, and to provide editors with a
   sustainability lexicon, definitions, and priorities to carry out that
   task.  As an added benefit, by including sustainability
   considerations, it will be possible to optimize for not only
   performance parameters but also sustainability ones, through
   respective trade-offs in our protocols and systems.

   We also envision that on top of minimizing the environmental impact
   of our technologies and helping consumers identify and reduce the
   environmental impact of their use, we can also make a positive impact
   on other systems.  E.g., use our technologies to choose greener and
   more efficient sources of power, control HVAC systems efficiently,
   etc.

4.1.  Call to Action

   The intention of this document is multifaceted: establish definitions
   and a lexicon for sustainability, characterize environmental
   implications of internetworking technologies, and provide specific
   guidelines for designers and implementers.

   Making these objectives actionable involves:

   1.  Familiarize yourself with the environmental sustainability terms,

   2.  understand the environmental sustainability implications to
       protocol and architecture, and




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   3.  consider, qualify, quantify, and explain the specific guidelines
       in Section 3 as you develop protocols, extensions, and
       architectures.

5.  IANA Considerations

   This document has no IANA actions.

6.  Security Considerations

   Sustainable practices offer many environmental, economic, and social
   benefits, and security is a route to sustainability rather than a
   hurdle to clear.  However, incorporating sustainability into network
   protocols and systems introduces new dimensions of trust.  Many
   sustainability-related decisions may rely on external or distributed
   data sources, such as carbon intensity feeds, energy consumption
   telemetry, or environmental metrics shared between operators or
   facilities.  It is important to consider the authenticity, integrity,
   and provenance of this data, especially when such information is used
   to trigger automated changes in network behavior.

   Protocols and systems should therefore support mechanisms to verify
   the origin and integrity of sustainability data received from
   external parties.  For example, carbon intensity signals could be
   signed or fetched over authenticated and encrypted channels.  Data
   from managed network elements (e.g., smart power supplies, cooling
   systems) should be exposed through secure interfaces with appropriate
   access control and auditability.  Where distributed coordination is
   involved, such as in multi-domain sustainability-aware routing, there
   is risk of misinformation, either accidental or malicious, impacting
   global optimization decisions.

   Moreover, sustainability-related telemetry may reveal information
   about network usage patterns, equipment lifecycle stages, or
   infrastructure sourcing.  Care must be taken to ensure that such
   disclosures do not leak sensitive operational, competitive, or
   geographical data.  Implementations should consider privacy-
   preserving techniques, such as aggregation, obfuscation, or
   differential privacy, especially in shared or public reporting
   contexts.

   Security in the sustainability context is not only about protecting
   the network from external threats, but also about ensuring
   trustworthy, private, and verifiable environmental data exchange.
   Without appropriate security, sustainability efforts may be
   undermined by unreliable data, misreporting, or abuse.





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7.  Acknowledgements

   This document is created greatly leveraging ideas and text from
   [I-D.cparsk-eimpact-sustainability-considerations], and consequently
   acknowledges all the many contributions that improved it.

8.  Informative References

   [I-D.cparsk-eimpact-sustainability-considerations]
              Pignataro, C., Rezaki, A., Krishnan, S., ElBakoury, H.,
              and A. Clemm, "Sustainability Considerations for
              Internetworking", Work in Progress, Internet-Draft, draft-
              cparsk-eimpact-sustainability-considerations-07, 24
              January 2024, <https://datatracker.ietf.org/doc/html/
              draft-cparsk-eimpact-sustainability-considerations-07>.

   [I-D.pignataro-green-enviro-sust-terminology]
              Pignataro, C., Rezaki, A., ElBakoury, H., and S. Prabhu,
              "Environmental Sustainability Terminology and Concepts",
              Work in Progress, Internet-Draft, draft-pignataro-green-
              enviro-sust-terminology-02, 12 May 2025,
              <https://datatracker.ietf.org/doc/html/draft-pignataro-
              green-enviro-sust-terminology-02>.

Authors' Addresses

   Carlos Pignataro (editor)
   Blue Fern Consulting
   United States of America
   Email: cpignata@gmail.com, carlos@bluefern.consulting


   Ali Rezaki
   Nokia
   Germany
   Email: ali.rezaki@nokia.com


   Jari Arkko
   Ericsson
   Email: jari.arkko@ericsson.com


   Alexander Clemm
   Futurewei
   2220 Central Expressway
   Santa Clara,  CA 95050
   United States of America



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   Email: ludwig@clemm.org


   Hesham ElBakoury
   Independent Consultant
   United States of America
   Email: helbakoury@gmail.com


   Shailesh Prabhu
   Nokia
   India
   Email: shailesh.prabhu@nokia.com






































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