Network Working Group                                  C. Pignataro, Ed.Internet-Draft                                      Blue Fern ConsultingIntended status: Informational                                 A. RezakiExpires: 14 May 2026                                               Nokia                                                             S. Krishnan                                                                   Cisco                                                                J. Arkko                                                                Ericsson                                                                A. Clemm                                                               Sympotech                                                            H. ElBakoury                                                  Independent Consultant                                                               S. Prabhu                                                                   Nokia                                                        10 November 2025     Architectural Considerations for Environmental Sustainability         draft-pignataro-enviro-sustainability-architecture-03Abstract   This document describes several of the design tradeoffs involved in   optimizing for sustainability along with the other common networking   metrics such as performance and availability.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.Copyright Notice   Copyright (c) 2025 IETF Trust and the persons identified as the   document authors.  All rights reserved.Pignataro, et al.          Expires 14 May 2026                  [Page 1]Internet-Draft     Sustainability Arch Considerations      November 2025   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   and restrictions with respect to this document.Table of Contents   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3   2.  Architectural Considerations of Environmental           Sustainability  . . . . . . . . . . . . . . . . . . . . .   3     2.1.  Design Tradeoffs  . . . . . . . . . . . . . . . . . . . .   3     2.2.  Multi-Objective Optimization  . . . . . . . . . . . . . .   4     2.3.  How Much Resiliency is Really Needed? . . . . . . . . . .   5       2.3.1.  Redundancy and Sustainability . . . . . . . . . . . .   6     2.4.  How Much are Performance and Quality of Experience           Compromised?  . . . . . . . . . . . . . . . . . . . . . .   6     2.5.  End-to-End Sustainability . . . . . . . . . . . . . . . .   7     2.6.  Attributional and Consequential Models  . . . . . . . . .   7     2.7.  The Role of Network Management and Orchestration  . . . .   8   3.  Sustainability Requirements and Phases  . . . . . . . . . . .  11     3.1.  Phase 1: Visibility . . . . . . . . . . . . . . . . . . .  11     3.2.  Phase 2: Insights and Recommendations . . . . . . . . . .  12     3.3.  Phase 3: Self-optimization and Automation . . . . . . . .  12       3.3.1.  Cycle of Phases . . . . . . . . . . . . . . . . . . .  12   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  13   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  13   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  13   7.  Informative References  . . . . . . . . . . . . . . . . . . .  14   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  141.  Introduction   Over the past decade, there has been increased awareness of the   environmental sustainability impact produced by the widespread   adoption of the Internet and internetworking technologies.  The   impact of Internet technologies has been overwhelmingly positive over   the past years (e.g., providing alternatives to travel, enabling   remote and hybrid work, enabling technology-based endangered species   conservation, etc.), and there is still room for improvement.Pignataro, et al.          Expires 14 May 2026                  [Page 2]Internet-Draft     Sustainability Arch Considerations      November 2025   At the same time, internetworking technologies themselves have a   significant environmental footprint.  Reducing this footprint and   making network deployments environmentally more sustainable becomes a   matter of increasing importance to network providers for various   reasons, including the desire to reduce operational expenses   associated with energy usage, regulatory pressures related to Net   Zero mandates, and corporate citizenship demands from customers to   become "greener".   Efforts to make internetworking more sustainable may in some cases   conflict with other important goals, such as network availability,   resilience against sudden spikes in traffic demand, and (at least in   some cases) Quality of Experience.  For example, a network operator   might want to include excess capacity in their network to be able to   absorb sudden spikes in demand and provision additional paths to   increase resilience against failures.  However, doing so may involve   powering up additional ports and equipment, resulting in higher   energy usage and increased greenhouse gas emissions, thus   compromising sustainability goals.  This indicates that there are   certain choices that a network operator has to make, some of which   may involve tradeoffs between goals.   This document describes some of the tradeoffs that could be involved   while optimizing for sustainability in addition to or in lieu of   traditional metrics such as performance or availability.  Further, it   discusses how Internet technologies can be used to help other fields   become more sustainable.   Specifically, this document details environmental sustainability   implications to Internet protocols, architectures, and technologies.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.2.  Architectural Considerations of Environmental Sustainability2.1.  Design Tradeoffs   Traditionally, digital communication networks are optimized for a   specific set of criteria that serve as proxies for business metrics.   A network operator providing services to their customers intends to   maximize profits, by increasing top-line revenue and decreasing   bottom-line associated costs.  This directly translates to goals of   optimizing performance and availability, while reducing various   costs.Pignataro, et al.          Expires 14 May 2026                  [Page 3]Internet-Draft     Sustainability Arch Considerations      November 2025   Most recently, various forces elevate the need for sustainability in   networking technologies and architectures, to quantify and minimize   negative environmental impact.   Optimizing only network availability (e.g., by having excess capacity   and backup paths) or optimizing only performance (e.g., by increasing   speeds or selecting paths based solely on delays) can seemingly be in   opposition to optimizing sustainability objectives.  For a given   application, use-case, or vertical realization of technology, a   Pareto-efficient choice can potentially improve sustainability   without sacrificing availability or performance beyond the   application tolerance.  That is, a win-win.   Consequently, network architects and designers are presented with a   set of new design tradeoffs: a multi-objective optimization that   satisfies broader requirements and global optima for availability,   performance, and sustainability simultaneously.  This is not unlike   the doughnut economics model concept described in [Doughnut].2.2.  Multi-Objective Optimization   To understand this new model, we can analyze a simplified example.   Assume the following topology, passing traffic from A to B:                           A                           |                      +----------+                      | Router 1 |------------+                      +----------+            |                       | | | | |         +----------+                       | | | | |         | Router 3 |                       | | | | |         +----------+                      +----------+            |                      | Router 2 |------------+                      +----------+                           |                           B       Figure 1: Simplified Network for Multi-Objective Optimization   Router 1 is directly connected to Router 2 through five parallel   links, of 10 Gbps each.  Router 1 can also reach Router 2 through   Router 3 with 40 Gbps links between Router 1 and Router 3, and   between Router 3 and Router 2.  Let's assume that the capacity-   planned traffic between A and B equals 15 Gbps.Pignataro, et al.          Expires 14 May 2026                  [Page 4]Internet-Draft     Sustainability Arch Considerations      November 2025   In this scenario, a topology optimized for performance and   availability/resiliency would have all links and routers on, and   would likely forward traffic using two of the parallel links.   Utilizing the path through Router 3 might lower performance, but it   serves as a backup path.   On the other hand, when we add sustainability as a consideration,   different options present themselves, each of which involves a   tradeoff.  One of the options is to remove from the topology Router 3   and associated links, and shutdown links and optics in two or three   of the parallel links.  This will allow the conservation of energy   that will no longer be required to operate Router 3 and the affected   links.  Another option is to completely shutdown all the parallel   links and route traffic through Router 3 (i.e., not maximizing   performance alone, but maximizing at the time performance,   availability and resiliency, and sustainability.)  The choice between   these two options, as well as the option to stick with the original   topology, will depend on choices that the network operator will have   to make, taking into account the aggregate sustainability metrics of   network elements in each of the two topologies as well as the effect   these choices will have on availability/resiliency which will be   reduced as a result.   Another option is to use flexible Ethernet, where the five links   combined are aggregated into one active virtual link which has 15   Gbps, and another inactive link of 35 Gbps of capacity -- although a   physical link cannot be half-active and half-inactive as far as PHY   and optics are concerned.2.3.  How Much Resiliency is Really Needed?   When we add sustainability considerations, resiliency is not the   single objective to optimize.   There are many methods to improve network resiliency, including a   design eliminating single-points-of-failure, performing software   safe-release selections and upgrades, deploying network real-time   testing systems (including operations, administration, and   maintenance (OAM) tools, monitoring systems (e.g., [RFC8403]), chaos-   based testing, and site reliability engineering (SRE) principles),   and utilizing redundancy across network elements as well as across a   topology.  Each one of these methods incurs also a sustainability   cost.  Yet, the functions for resiliency improvement and   sustainability cost for each of these methods are not the same.   Considering sustainability means quantifying its impact in the   decision of how to improve resiliency, and how much is needed.Pignataro, et al.          Expires 14 May 2026                  [Page 5]Internet-Draft     Sustainability Arch Considerations      November 20252.3.1.  Redundancy and Sustainability   Let's first explore redundancy.  For example, consider the ratio of   overall network capacity (in bandwidth, compute power, etc.) over the   used network capacity, and let's call it "Redundancy Index".  If this   number is one, there's no redundancy; and as the ratio grows, so does   the potentially unused capacity that could be utilized in a failure   event.  Similarly, consider the values of sustainability metrics for   when the Redundancy Index is one and for when it is two.  These   border points might give an indication of the slope for each   objective function.   Adequate Redundancy:      In order to determine how much redundancy needs to be built into      the overall network capacity, which can be referred to as      "adequate redundancy to avoid network outings", it will be      important to (1) measure the bandwidth of attacks against the      overall network capacity; and (2) understand how quickly "high      bandwidth" attacks can be detected and diverted.  Measuring these      results over time may lead the "adequate redundancy" to become      higher over time.   Justified Redundancy:      Traditionally, network operators would be much less worried about      energy use than about the possibility that the network would have      brownout or backout outages - thus the measuring will help better      balance the "adequate redundancy" against the related energy use,      resulting in turn in "justified redundancy": a balance between      costs and benefits, with energy use as well as material use as a      clear cost factor.   Please note that "justified redundancy" may be higher than "adequate   redundancy" when we manage to organize the redundancy in a multi-   layer fashion: (1) capacity that is "always on" and always uses   energy; (2) capacity that can turn on quickly when needed; (and   possibly (3) capacity that is "on the shelf" (even in the box) but   ready to be deployed quickly when needed.)2.4.  How Much are Performance and Quality of Experience Compromised?   Network performance and Quality of Experience have always played an   important role in the development of networking technology.  Key   parameters such as latency, jitter, and loss as well as their impact   on the quality that the users of networked applications experience   are well understood, the optimization of those parameters and the   adherence to corresponding service level objectives being an   important goal in most network deployments.  However, the desire to   improve sustainability and energy efficiency can conflict with thosePignataro, et al.          Expires 14 May 2026                  [Page 6]Internet-Draft     Sustainability Arch Considerations      November 2025   goals.  For example, in order to ensure minimal latency, a network   operator may need to provision additional paths that require   additional ports that need to be powered, instead of relying on a   topology with fewer links and nodes.  Such a topology might result in   greater power efficienc as a result more resources being shared, but   it could also result in longer paths and an increased possibility for   congestion, both of which would be detrimental to latency and   associated Quality of Experience.   This implies a tradeoff between different goals.  The challenge for   operators lies in finding the sweet spot in which acceptable network   performance is obtained and a point of diminishing returns is reached   at which any incremental further performance improvement would come   at the expense of significant deterioration in energy usage.2.5.  End-to-End Sustainability   The networking industry is in the starting phases of addressing this   objective.  We are seeing a sprinkling of sustainability features   across the networking stack and components of devices, whether it is   on forwarding chips, power supplies, optics, and compute.  Many of   those optimizations and features are typically local in nature, and   widely scattered across different elements of a network architecture.   An opportunity for maximizing the positive environmental impact of   these technologies calls for a more cohesive and complementary view   that spans the complete product lifecycle for hardware and software,   as well as how some of these features work in unison.   For example, features that provide energy saving modes for devices   can be dynamically managed when the network utilization is such that   performance would not significantly suffer.  A core router, instead   of becoming obsolete due to the need for higher throughput in the   core, could become a future edge/access router.  That is an example   of reuse and repurpose, before recycling.  There are benefits of   macro-optimizations by clustering in specific features, versus micro-   optimizing locally without awareness of the network context.2.6.  Attributional and Consequential Models   Many of the subtleties and nuances of the measurement of GHG and   environmental impacts stem from the very important distinction   between attributional and consequential models.  Detailed definitions   can be found at [UNEP-LCA].   Attributional:Pignataro, et al.          Expires 14 May 2026                  [Page 7]Internet-Draft     Sustainability Arch Considerations      November 2025      Also referred to as Allocational models, start by allocating or      attributing quantities (e.g., GHG emissions) to entities (e.g., a      router, a building, a town), and performing comparisons between      the measurements (or estimates) of the quantity by the entities.   Consequential:      Perform the measurement of the quantity by establishing a baseline      scenario (e.g., before feature introduction) and a modified      scenario (e.g., after the feature introduction).   While both models are quite different, they do use the same terms and   frames of references, measures, and language.  Without explicit   clarifications, they are prone to confusion.   For example, measuring the carbon footprint attributed to a batch   process or a workload based on its energy efficiency would not   consider that the hardware is still there running.  When is it most   effective to charge battery-powered devices, during the night when   there's less load, or during the day when there's solar energy?  In   other words, if a person who commutes by train to their office five   days a week starts working from home two days a week, there could be   an attributional reduction of GHG emissions, yet the train still   continues running equally.  However, if that person commutes by   combustion-engine car alone, the consequences are different.   Considering the attributional versus consequential distinction, there   are some implications and a potential corollaries:   *  For an environmental-impact analysis, it is critical to explicitly      cite the model used, as well as clearly define the boundary.   *  The activities that we embark upon as internetworking and protocol      designers - including the ones targeting reduction of negative      environmental impacts - have an energy footprint of themselves.   *  "Do no harm" in the context of improving sustainability of      networks is to look beyond bounded attributions and consider (both      intended and unintended) consequences.2.7.  The Role of Network Management and Orchestration   Deployment and operational aspects play a critical role in making   networks more sustainable.  A detailed explanation of that role, the   associated challenges, as well as an outline of solution approaches   is provided in [RFC9845].  Here are some areas in which network   management can help make networks more sustainable; for a more   extensive treatment, please refer to that document.Pignataro, et al.          Expires 14 May 2026                  [Page 8]Internet-Draft     Sustainability Arch Considerations      November 2025   Dimensioning:      Networks should be deployed and configured with sufficient      capacity to serve their intended purpose.  At the same time,      overprovisioning and providing too many resources should be      avoided, as this results in waste and unnecessary environmental      impact.  Network management can facilitate proper dimensioning of      networks by providing the methods and tools that allow to assess      network usage, determine required capacities, identify trends to      allow to proactively accommodate traffic growth and new services.   Network Optimization:      Network management applications can help solve difficult network      optimization problems involving multiple parameters, multiple and      sometimes conflicting objectives, and mitigation of tradeoffs.      Network optimization examples include maximization of utilization      or of aggregate QoE scores, minimization of the possibility of SLA      violations with a given amount of network resources, or      optimization of the cost of configured paths.  Network metrics      related to sustainability are another set of parameters that can      be optimized.   Rapid Discovery and Provisioning Schemes:      One of the biggest potential opportunities in reducing      environmental impact of networks concerns the ability to power      resources such as equipment or line cards down when they are      momentarily not needed due to swings in traffic demands.  In      general, this involves fully automated management control loops      with very short time scales.  Network management can enable such      schemes, involving algorithms that determine and control the rapid      de- and re-commissioning of networking resources, as well as the      necessary control protocols that facilitate aspects such as rapid      resource discovery, reprovisioning, or reconvergence of management      state.   Policy-Driven Sustainability Enforcement:      Network management systems can play a pivotal role in enforcing      explicit sustainability policies, much like how QoS, security, or      routing policies are enforced today.  These policies can express      environmental objectives such as limiting power consumption within      specific network domains, prioritizing traffic through paths      powered by renewable energy, or dynamically adjusting service      parameters to meet carbon footprint targets.  Such policy-driven      approaches allow sustainability intents to be specified at a high      level and translated into actionable configurations using      orchestration frameworks.  By embedding sustainability into policy      and intent-based networking models, operators gain precise control      over how environmental goals are operationalized and maintained      across diverse services and tenants.Pignataro, et al.          Expires 14 May 2026                  [Page 9]Internet-Draft     Sustainability Arch Considerations      November 2025   Inter-Domain Sustainability Coordination:      Sustainability optimization must extend beyond individual      administrative domains to realize its full potential at Internet      scale.  Network management and orchestration systems can be      enhanced to support inter-domain coordination mechanisms that      allow operators to share sustainability-related metadata, such as      real-time carbon intensity of regional infrastructure, green      routing preferences, or energy availability status.  By enabling      cooperative decision-making, networks can collectively route      traffic in ways that reduce aggregate environmental impact.  This      requires the definition of interoperable data models, trust      frameworks, and privacy-preserving methods for sharing      sustainability metrics across organizational boundaries.  As      sustainability becomes a global imperative, inter-domain      orchestration will be essential to align local optimizations with      broader planetary goals.      To enable end-to-end sustainability, environmental objectives must      persist across the full service path, including ingress, transit,      and egress domains.  This requires a mechanism for expressing      sustainability intents (e.g., “carbon-sensitive” or “low-energy”)      at the service origin and ensuring they are respected downstream.      These intents may influence route selection, resource allocation,      and power state decisions in intermediate networks.  Failure to      propagate such goals may result in sustainability regressions that      cancel out upstream efforts.      Achieving this coordination demands standardized sustainability      telemetry formats and semantic models.  Exchanged data may include      per-domain carbon intensity, real-time energy sourcing, or      equipment-level energy efficiency indicators.  Agreement on common      ontologies and encoding formats will be essential to ensure      compatibility across vendor and operator implementations.      Beyond metrics, cooperative orchestration protocols will be needed      to act on this shared information.  For example, inter-domain      green routing agreements may optimize for end-to-end energy      profiles in addition to latency or cost.  Sustainability-aware      SLAs could encode carbon or energy constraints alongside      traditional service guarantees.  Trust boundaries, policy      asymmetries, and privacy concerns may necessitate abstraction      layers, optional disclosure levels, or brokered negotiation      intermediaries.   In addition to those aspects, perhaps the most important role of   network management is to provide network operators with the necessary   visibility into how and where power is used in their network.  This   is required in order to assess where the network stands in terms ofPignataro, et al.          Expires 14 May 2026                 [Page 10]Internet-Draft     Sustainability Arch Considerations      November 2025   sustainability.  It also allows to track progress over time, compare   different alternatives for their effectiveness, and generally to   facilitate network sustainability optimization.  Providing this   visibility requires the definition of metrics and corresponding   instrumentation of the network so that those metrics can be   monitored, assessed, compared, and improved.3.  Sustainability Requirements and Phases   The architectural considerations for environmental sustainability   cannot always be achieved at the same time and we expect the   following high level phases:   1.  Visibility: In this phase we focus on the measurement and       collection of metrics.   2.  Insights and Recommendations: In this phase we focus on deriving       insights and providing recommendations that can be acted upon       manually over large time scales.   3.  Self-Optimization via Automation: In this phase we build       awareness into the systems to automatically recognize       opportunities for improvement and implement them.3.1.  Phase 1: Visibility   Visibility represents collecting and organizing data in a standard   vendor agnostic manner.  The first step in improving our   environmental impact is to actually measure it in a clear and   consistent manner.  The IETF, IRTF and the IAB have a long history of   work in this field, and this has greatly helped with the   instrumentation of network equipment in collecting metrics for   network management, performance, and troubleshooting.  On the   environmental-impact side though, there has been a proliferation of a   wide variety of vendor extensions based on these standards.  Without   a common definition of metrics across the industry and widespread   adoption we will be left with ill-defined, potentially redundant,   proprietary, or even contradicting metrics.  Similarly, we also need   to work on standard telemetry for collecting these metrics so that   interoperability can be achieved in multi-vendor networks.Pignataro, et al.          Expires 14 May 2026                 [Page 11]Internet-Draft     Sustainability Arch Considerations      November 20253.2.  Phase 2: Insights and Recommendations   Once the metrics have been collected, categorized, and aggregated in   a common format, it would be straightforward to visualize these   metrics and allow consumers to draw insights into their GHG and   energy impact.  The visualizations could take the form of high-level   dashboards that provide aggregate metrics and potentially some form   of maturity continuum.  We think this can be accomplished using   reference implementations of the standards developed in "Phase 1:   Visibility".  We do expect vendors and other open projects to   customize this and incorporate specific features.  This will allow   identifying sources of environmental impact and address any potential   issues through operational changes, creation of best-practices, and   changes towards a greener, more environmentally friendly equipment,   software, platforms, applications, and protocols.3.3.  Phase 3: Self-optimization and Automation   Manually making changes as mentioned in "Phase 2: Insights and   Recommendations" works for changes needed on large timescales but   does not scale to improvements on smaller scales (i.e., it is   impractical in many levels for an operator to be looking at a   dashboard monitoring usage and making changes in real-time 24x7).   There is a need to provision some amount of self-awareness into the   network itself, at various layers, so that it can identify   opportunities for improvement, implement the necessary changes, and   measure the effects to complete the feedback loop.  The goals of the   consumers can be stated declaratively, and the networks can   continually use mechanisms such as machine learning (ML), deep   learning (DL), and artificial intelligence (AI) with an additional   goal to optimize for improvements in the environmental impact.  These   include, for example:   *  Discovery and advertisement of networking characteristics that      have either direct or indirect environmental impact,   *  greener networking protocols that can move traffic onto more      energy efficient paths, directing topological graphs to optimize      environmental impacts, and   *  protocols that can instruct equipment to move under-utilized links      and devices into low-energy modes.3.3.1.  Cycle of Phases   The three phases run in an iterative fashion, such that after phases   1, 2, and 3 are completed for an interation, there will be an added   awareness of what (else) to collect back to phase 1.Pignataro, et al.          Expires 14 May 2026                 [Page 12]Internet-Draft     Sustainability Arch Considerations      November 2025   Further, sustainability-aware self-optimization is something to   explore in Autonomic Networking.4.  IANA Considerations   This document has no IANA actions.5.  Security Considerations   Sustainable practices offer many environmental, economic, and social   benefits, and security is a route to sustainability rather than a   hurdle to clear.      The creation of sustainability features for an element or a system      should not weaken or compromise their security posture, nor should      it increase the surface of attack or create attack vectors.      -  Sustainability metrics and data models ought to describe how to         secure the sustainability data exposed and surfaced through         telemetry.      -  Sustainability control capabilities, as for example for power         management, should consider potential attacks leveraging those         controls.  Setting a device on low-power or power-save modes         during peak traffic can be a denial-of-service attack vector,         negatively impacting end-to-end services.      The development of security features should, in turn, balance the      environmental impact and sustainability considerations detailed in      this document.      -  Computational increase on cryptographic operations can result         in higher power use.  Since generally the increase of energy         required is not linear with the increase of computational         complexity, there's a desire to satisfy security requirements         while minimizing environmental impact.      -  Proof-of-Work schemes' and AI models' energy consumption also         grows non-linearly as a function of the precision achieved.  In         these, perfect is the enemy of good, and bounding precision         through specifications supports sustainable compute         considerations.6.  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.Pignataro, et al.          Expires 14 May 2026                 [Page 13]Internet-Draft     Sustainability Arch Considerations      November 20257.  Informative References   [Doughnut] Wikipedia, "Doughnut (economic model)", 13 October 2023,              <https://en.wikipedia.org/wiki/Doughnut_(economic_model)>.   [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>.   [RFC8403]  Geib, R., Ed., Filsfils, C., Pignataro, C., Ed., and N.              Kumar, "A Scalable and Topology-Aware MPLS Data-Plane              Monitoring System", RFC 8403, DOI 10.17487/RFC8403, July              2018, <https://www.rfc-editor.org/info/rfc8403>.   [RFC9845]  Clemm, A., Ed., Pignataro, C., Ed., Westphal, C.,              Ciavaglia, L., Tantsura, J., and M. Odini, "Challenges and              Opportunities in Management for Green Networking",              RFC 9845, DOI 10.17487/RFC9845, October 2025,              <https://www.rfc-editor.org/info/rfc9845>.   [UNEP-LCA] "Global guidance principles for life cycle assessment              databases : a basis for greener processes and products",              2011, <https://www.lifecycleinitiative.org/library/global-              guidance-principles-for-lca-databases-a-basis-for-greener-              processes-and-products/>.Authors' Addresses   Carlos Pignataro (editor)   Blue Fern Consulting   United States of America   Email: cpignata@gmail.com, carlos@bluefern.consultingPignataro, et al.          Expires 14 May 2026                 [Page 14]Internet-Draft     Sustainability Arch Considerations      November 2025   Ali Rezaki   Nokia   Germany   Email: ali.rezaki@nokia.com   Suresh Krishnan   Cisco Systems, Inc.   United States of America   Email: sureshk@cisco.com   Jari Arkko   Ericsson   Email: jari.arkko@ericsson.com   Alexander Clemm   Sympotech   United States of America   Email: ludwig@clemm.org   Hesham ElBakoury   Independent Consultant   United States of America   Email: helbakoury@gmail.com   Shailesh Prabhu   Nokia   India   Email: shailesh.prabhu@nokia.comPignataro, et al.          Expires 14 May 2026                 [Page 15]