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Internet Research Task Force (IRTF) A. Clemm, Ed. Internet Research Task Force (IRTF) A. Clemm, Ed.
Request for Comments: 9845 Independent Request for Comments: 9845 Sympotech
Category: Informational C. Pignataro, Ed. Category: Informational C. Pignataro, Ed.
ISSN: 2070-1721 NC State University & Blue Fern Consulting ISSN: 2070-1721 NC State University & Blue Fern Consulting
C. Westphal C. Westphal
University of California, Santa Cruz
L. Ciavaglia L. Ciavaglia
Nokia Nokia
J. Tantsura J. Tantsura
Nvidia Nvidia
M-P. Odini M-P. Odini
September 2025 September 2025
Challenges and Opportunities in Management for Green Networking Challenges and Opportunities in Management for Green Networking
Abstract Abstract
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The science behind greenhouse gas emissions and their relationship The science behind greenhouse gas emissions and their relationship
with climate change is complex. However, there is overwhelming with climate change is complex. However, there is overwhelming
scientific consensus pointing toward a clear correlation between scientific consensus pointing toward a clear correlation between
climate change and a rising amount of greenhouse gases in the climate change and a rising amount of greenhouse gases in the
atmosphere. When we say 'greenhouse gases' or GHG, we are referring atmosphere. When we say 'greenhouse gases' or GHG, we are referring
to gases in the Earth's atmosphere that trap heat and contribute to to gases in the Earth's atmosphere that trap heat and contribute to
the greenhouse effect. They include carbon dioxide (CO2), methane the greenhouse effect. They include carbon dioxide (CO2), methane
(CH4), nitrous oxide (N2O), and fluorinated gases (as covered under (CH4), nitrous oxide (N2O), and fluorinated gases (as covered under
the Kyoto Protocol and Paris Agreement). In terms of emissions from the Kyoto Protocol and Paris Agreement). In terms of emissions from
human activity, the dominant greenhouse gas is CO2; consequently, it human activity, the dominant greenhouse gas is carbon dioxide (CO2).
often becomes shorthand for "all GHGs". However, other gases are CO2 is emitted in the process of burning fuels to generate energy
also converted into "CO2-equivalents", or CO2e. One greenhouse gas that is used, for example, to power electrical devices such as
of particular concern, but by no means the only one, is carbon networking equipment. Those fuels often include fossil fuels (such
dioxide (CO2). Carbon dioxide is emitted in the process of burning as oil), which releases CO2 that had long been removed from the
fuels to generate energy that is used, for example, to power earth's atmosphere, as opposed to the use of renewable or sustainable
electrical devices such as networking equipment. Notable here is the fuels that do not "add" to the amount of CO2 in the atmosphere.
use of fossil fuels (such as oil, which releases CO2 that had long Other GHGs such as CH4 and N2O are associated with electricity
been removed from the earth's atmosphere), as opposed to the use of generation as well. Although they are emitted in smaller quantities,
renewable or sustainable fuels that do not "add" to the amount of CO2 they have an even higher Global Warming Potential (GWP). To
in the atmosphere. There are additional gases associated with facilitate accounting for them, they are collectively simply
electricity generation, in particular methane (CH4) and nitrous oxide converted into CO2 equivalents (CO2e).
(N2O). Although they exist in smaller quantities, they have an even
higher Global Warming Potential (GWP).
Greenhouse gas emissions are in turn correlated with the need to Greenhouse gas emissions are in turn correlated with the need to
power technology, including networks. Reducing those emissions can power technology, including networks. Reducing those emissions can
be achieved by reducing the amount of fossil fuels needed to generate be achieved by reducing the amount of fossil fuels needed to generate
the energy that is needed to power those networks. This can be the energy that is needed to power those networks. This can be
achieved by improving the energy mix to include increasing amounts of achieved by improving the energy mix to include increasing amounts of
low-carbon and/or renewable (and hence sustainable) energy sources, low-carbon and/or renewable (and hence sustainable) energy sources,
such as wind or solar. It can also be achieved by increasing energy such as wind or solar. It can also be achieved by increasing energy
savings and improving energy efficiency so that the same outcomes are savings and improving energy efficiency so that the same outcomes are
achieved while consuming less energy in the first place. achieved while consuming less energy in the first place.
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hosting meetings three times a year (see [IETF-Net0]). It conducted hosting meetings three times a year (see [IETF-Net0]). It conducted
a study of the carbon emissions of a typical meeting and found out a study of the carbon emissions of a typical meeting and found out
that 99% of the emissions were due to air travel. In the same vein, that 99% of the emissions were due to air travel. In the same vein,
[Framework] compared an in-person with a virtual meeting and found a [Framework] compared an in-person with a virtual meeting and found a
reduction in energy of 66% for a virtual meeting. These findings reduction in energy of 66% for a virtual meeting. These findings
confirm that networking technology can reduce emissions when acting confirm that networking technology can reduce emissions when acting
as a virtual substitution for physical events. as a virtual substitution for physical events.
That said, networks themselves consume significant amounts of energy. That said, networks themselves consume significant amounts of energy.
Therefore, the networking industry has an important role to play in Therefore, the networking industry has an important role to play in
meeting sustainability goals and not just by enabling others to meeting sustainability goals, not just by enabling others to reduce
reduce their reliance on energy but by also reducing its own. Future their reliance on energy but also by reducing its own. Future
networking advances will increasingly need to focus on becoming more networking advances will increasingly need to focus on becoming more
energy efficient and reducing the carbon footprint, for reasons of energy efficient and reducing the carbon footprint, for reasons of
both corporate responsibility and economics. This shift has already both corporate responsibility and economics. This shift has already
begun, and sustainability is becoming an important concern for begun, and sustainability is becoming an important concern for
network providers. In some cases, such as in the context of network providers. In some cases, such as in the context of
networked data centers, the ability to procure enough energy becomes networked data centers, the ability to procure enough energy becomes
a bottleneck, prohibiting further growth, and greater sustainability a bottleneck, prohibiting further growth, and greater sustainability
thus becomes a business necessity. thus becomes a business necessity.
For example, in its annual report, Telefónica reports that in 2024, For example, in its annual report, Telefónica reports that in 2024,
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to steer traffic along those paths. (As mentioned earlier, other to steer traffic along those paths. (As mentioned earlier, other
proxy measures could be used for carbon footprint, such as energy- proxy measures could be used for carbon footprint, such as energy-
efficiency ratings of traversed equipment.) It also includes aspects efficiency ratings of traversed equipment.) It also includes aspects
such as considering the incremental carbon footprint in routing such as considering the incremental carbon footprint in routing
decisions. Optimizing cost has long been an area of focus in decisions. Optimizing cost has long been an area of focus in
networking; many of the existing mechanisms can be leveraged for networking; many of the existing mechanisms can be leveraged for
greener networking simply by introducing the carbon footprint as a greener networking simply by introducing the carbon footprint as a
cost factor. Low-hanging fruit includes adding carbon-related cost factor. Low-hanging fruit includes adding carbon-related
parameters as a cost parameter in control planes, whether distributed parameters as a cost parameter in control planes, whether distributed
(e.g., IGP) or conceptually centralized via SDN controllers. (e.g., IGP) or conceptually centralized via SDN controllers.
Likewise, there are opportunities to correctly place functionality in Likewise, there are opportunities to smartly place functionality in
the network for optimal effectiveness. An example is placement of the network for optimal effectiveness. An example is placement of
virtualized network functions in carbon-optimized ways. For example, virtualized network functions in carbon-optimized ways. For example,
virtualized network functions can be cohosted on fewer servers to virtualized network functions can be cohosted on fewer servers to
achieve higher server utilization, which is more effective from an achieve higher server utilization, which is more effective from an
energy and carbon perspective than larger numbers of servers with energy and carbon perspective than larger numbers of servers with
lower utilization. Likewise, they can be placed in close proximity lower utilization. Likewise, they can be placed in close proximity
to each other in order to avoid unnecessary overhead in long-distance to each other in order to avoid unnecessary overhead in long-distance
control traffic. control traffic.
Other opportunities concern adding carbon awareness to dynamic path Other opportunities concern adding carbon awareness to dynamic path
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Contributors Contributors
Michael Welzl Michael Welzl
University of Oslo University of Oslo
Email: michawe@ifi.uio.no Email: michawe@ifi.uio.no
Authors' Addresses Authors' Addresses
Alexander Clemm (editor) Alexander Clemm (editor)
Independent Sympotech
Los Gatos, CA Los Gatos, CA
United States of America United States of America
Email: ludwig@clemm.org Email: ludwig@clemm.org
Carlos Pignataro (editor) Carlos Pignataro (editor)
North Carolina State University & Blue Fern Consulting North Carolina State University & Blue Fern Consulting
United States of America United States of America
Email: cmpignat@ncsu.edu, carlos@bluefern.consulting Email: cmpignat@ncsu.edu, carlos@bluefern.consulting
Cedric Westphal Cedric Westphal
Department of Computer Science and Engineering
University of California, Santa Cruz
Email: westphal@ieee.org Email: westphal@ieee.org
Laurent Ciavaglia Laurent Ciavaglia
Nokia Nokia
Email: laurent.ciavaglia@nokia.com Email: laurent.ciavaglia@nokia.com
Jeff Tantsura Jeff Tantsura
Nvidia Nvidia
Email: jefftant.ietf@gmail.com Email: jefftant.ietf@gmail.com
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