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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
	skipping to change at line 120 ¶		skipping to change at line 120 ¶
	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.
	skipping to change at line 195 ¶		skipping to change at line 193 ¶
	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,
	skipping to change at line 969 ¶		skipping to change at line 967 ¶
	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
	skipping to change at line 1597 ¶		skipping to change at line 1595 ¶
	"Qualitative Communications for Augmented Reality and		"Qualitative Communications for Augmented Reality and
	Virtual Reality", 22nd IEEE International Conference on		Virtual Reality", 22nd IEEE International Conference on
	High Performance Switching and Routing (HPSR), pp. 1-6,		High Performance Switching and Routing (HPSR), pp. 1-6,
	DOI 10.1109/HPSR52026.2021.9481793, 2021,		DOI 10.1109/HPSR52026.2021.9481793, 2021,
	<https://doi.org/10.1109/HPSR52026.2021.9481793>.		<https://doi.org/10.1109/HPSR52026.2021.9481793>.
	[Wolf2014choicenet]		[Wolf2014choicenet]
	Tilman, W., Griffioen, J., Calvert, L., Dutta, R.,		Tilman, W., Griffioen, J., Calvert, L., Dutta, R.,
	Rouskas, G., Baldin, I., and A. Nagurney, "ChoiceNet:		Rouskas, G., Baldin, I., and A. Nagurney, "ChoiceNet:
	Toward an Economy Plane for the Internet", ACM SIGCOMM		Toward an Economy Plane for the Internet", ACM SIGCOMM
	Computer Communciations Review, vol. 44, no. 3, pp. 58-65,		Computer Communications Review, vol. 44, no. 3, pp. 58-65,
	DOI 10.1145/2656877.2656886, July 2014,		DOI 10.1145/2656877.2656886, July 2014,
	<https://doi.org/10.1145/2656877.2656886>.		<https://doi.org/10.1145/2656877.2656886>.
	Acknowledgments		Acknowledgments
	The authors thank Dave Oran for providing the information regarding		The authors thank Dave Oran for providing the information regarding
	covert channels using energy measurements and Mike King for an		covert channels using energy measurements and Mike King for an
	exceptionally thorough review and useful comments.		exceptionally thorough review and useful comments.
	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
	Email: westphal@ieee.org		Department of Computer Science and Engineering
			University of California, Santa Cruz
			Email: cedric@ucsc.edu
	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
	Marie-Paule Odini		Marie-Paule Odini
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