rfc9817v1.txt		rfc9817.txt
	Internet Research Task Force (IRTF) I. Kunze		Internet Research Task Force (IRTF) I. Kunze
	Request for Comments: 9817 K. Wehrle		Request for Comments: 9817 K. Wehrle
	Category: Informational RWTH Aachen		Category: Informational RWTH Aachen
	ISSN: 2070-1721 D. Trossen		ISSN: 2070-1721 D. Trossen
	Huawei		DaPaDOT Tech
	M-J. Montpetit		M-J. Montpetit
	McGill		SLICES-RI
	X. de Foy		X. de Foy
	InterDigital Communications, LLC		InterDigital Communications, LLC
	D. Griffin		D. Griffin
	M. Rio		M. Rio
	UCL		UCL
	July 2025		July 2025
	Use Cases for In-Network Computing		Use Cases for In-Network Computing
	Abstract		Abstract
	skipping to change at line 159 ¶		skipping to change at line 159 ¶
	is another objective of the use case descriptions. To achieve this,		is another objective of the use case descriptions. To achieve this,
	the following taxonomy is proposed to describe each of the use cases:		the following taxonomy is proposed to describe each of the use cases:
	Description: A high-level presentation of the purpose of the use		Description: A high-level presentation of the purpose of the use
	case and a short explanation of the use case behavior.		case and a short explanation of the use case behavior.
	Characterization: An explanation of the services that are being		Characterization: An explanation of the services that are being
	utilized and realized as well as the semantics of interactions in		utilized and realized as well as the semantics of interactions in
	the use case.		the use case.
	Existing Solutions: A description of current methods that may		Existing solutions: A description of current methods that may
	realize the use case (if they exist), though not claiming to		realize the use case (if they exist), though not claiming to
	exhaustively review the landscape of solutions.		exhaustively review the landscape of solutions.
	Opportunities: An outline of how COIN capabilities may support or		Opportunities: An outline of how COIN capabilities may support or
	improve on the use case in terms of performance and other metrics.		improve on the use case in terms of performance and other metrics.
	Research questions: Essential questions that are suitable for		Research questions: Essential questions that are suitable for
	guiding research to achieve the identified opportunities. The		guiding research to achieve the identified opportunities. The
	research questions also capture immediate capabilities for any		research questions also capture immediate capabilities for any
	COIN solution addressing the particular use case whose development		COIN solution addressing the particular use case whose development
	skipping to change at line 269 ¶		skipping to change at line 269 ¶
	(e.g., more suitable) devices, including PNDs, which have exposed the		(e.g., more suitable) devices, including PNDs, which have exposed the
	corresponding (COIN) program as individual (COIN) program instances		corresponding (COIN) program as individual (COIN) program instances
	to the (COIN) system by means of a service identifier. The result is		to the (COIN) system by means of a service identifier. The result is
	the equivalent to mobile function offloading, for possible reduction		the equivalent to mobile function offloading, for possible reduction
	of power consumption (e.g., offloading CPU-intensive process		of power consumption (e.g., offloading CPU-intensive process
	functions to a remote server) or for improved end-user experience		functions to a remote server) or for improved end-user experience
	(e.g., moving display functions to a nearby smart TV) by selecting		(e.g., moving display functions to a nearby smart TV) by selecting
	more suitably placed (COIN) program instances in the overall (COIN)		more suitably placed (COIN) program instances in the overall (COIN)
	system.		system.
	We can already see a trend toward supporting such functionality with		We can already see a trend toward supporting such functionality that
	relyiccng on dedicated cloud hardware (e.g., gaming platforms		relies on dedicated cloud hardware (e.g., gaming platforms rendering
	rendering content externally). We envision, however, that such		content externally). We envision, however, that such functionality
	functionality is becoming more pervasive through specific facilities,		is becoming more pervasive through specific facilities, such as
	such as entertainment parks or even hotels, in order to deploy needed		entertainment parks or even hotels, in order to deploy needed edge
	edge computing capabilities to enable localized gaming as well as		computing capabilities to enable localized gaming as well as non-
	non-gaming scenarios.		gaming scenarios.
	Figure 1 shows one realization of the above scenario, where a "DPR		Figure 1 shows one realization of the above scenario, where a "DPR
	app" is running on a mobile device (containing the partitioned COIN		app" is running on a mobile device (containing the partitioned COIN
	programs Display (D), Process (P) and Receive (R)) over a		programs Display (D), Process (P) and Receive (R)) over a
	programmable switching network, e.g., a Software-Defined Network		programmable switching network, e.g., a Software-Defined Network
	(SDN) here. The packaged applications are made available through a		(SDN) here. The packaged applications are made available through a
	localized "playstore server". The mobile application installation is		localized "playstore server". The mobile application installation is
	realized as a service deployment process, combining the local app		realized as a service deployment process, combining the local app
	installation with a distributed deployment (and orchestration) of one		installation with a distributed deployment (and orchestration) of one
	or more (COIN) programs on most suitable end systems or PNDs (here, a		or more (COIN) programs on most suitable end systems or PNDs (here, a
	skipping to change at line 1018 ¶		skipping to change at line 1018 ¶
	* RQ 4.1.3: How to find suitable tradeoffs regarding simplicity of		* RQ 4.1.3: How to find suitable tradeoffs regarding simplicity of
	the control function ("accuracy of the control") and		the control function ("accuracy of the control") and
	implementation complexity ("implementability")?		implementation complexity ("implementability")?
	* RQ 4.1.4: How to (dynamically) distribute simplified versions of		* RQ 4.1.4: How to (dynamically) distribute simplified versions of
	the global (control) function among COIN execution environments?		the global (control) function among COIN execution environments?
	* RQ 4.1.5: How to (dynamically) compose or recompose the		* RQ 4.1.5: How to (dynamically) compose or recompose the
	distributed control functions?		distributed control functions?
	* RQ 4.1.6: Can there be different control levels, e.g., "quite		* RQ 4.1.6: Can there be different control levels? For example,
	inaccurate & very low latency" (PNDs, deep in the network), "more		"quite inaccurate & very low latency" for PNDs deep in the
	accurate & higher latency" (more powerful COIN execution		network; "more accurate & higher latency" for more powerful COIN
	environments, farther away), "very accurate & very high latency"		execution environments that are farther away; and "very accurate &
	(cloud environments, far away)?		very high latency" for cloud environments that are far away.
	* RQ 4.1.7: Who decides which control instance is executed and which		* RQ 4.1.7: Who decides which control instance is executed and which
	information can be used for this decision?		information can be used for this decision?
	* RQ 4.1.8: How do the different control instances interact and how		* RQ 4.1.8: How do the different control instances interact and how
	can we define their hierarchy?		can we define their hierarchy?
	4.1.6. Additional Desirable Capabilities		4.1.6. Additional Desirable Capabilities
	In addition to the capabilities driven by the research questions		In addition to the capabilities driven by the research questions
	skipping to change at line 1106 ¶		skipping to change at line 1106 ¶
	or sampling frequency is often larger than required. Consequently,		or sampling frequency is often larger than required. Consequently,
	it is likely that more data is transmitted than is needed or desired,		it is likely that more data is transmitted than is needed or desired,
	prompting the deployment of filtering techniques. For example, COIN		prompting the deployment of filtering techniques. For example, COIN
	programs deployed in the on-premise network could filter out		programs deployed in the on-premise network could filter out
	redundant or undesired data before it leaves the premise using simple		redundant or undesired data before it leaves the premise using simple
	traffic filters, thus reducing the required (upload) bandwidths. The		traffic filters, thus reducing the required (upload) bandwidths. The
	available sensor data could be scaled down using standard statistical		available sensor data could be scaled down using standard statistical
	sampling, packet-based sub-sampling (i.e., only forwarding every n-th		sampling, packet-based sub-sampling (i.e., only forwarding every n-th
	packet), or using filtering as long as the sensor value is in an		packet), or using filtering as long as the sensor value is in an
	uninteresting range while forwarding with a higher resolution once		uninteresting range while forwarding with a higher resolution once
	the sensor value range becomes interesting (cf. [KUNZE-SIGNAL]).		the sensor value range becomes interesting (cf. [KUNZE-SIGNAL] and
	While the former variants are oblivious to the semantics of the		[TIRPITZ-REDUCIO]). While the former variants are oblivious to the
	sensor data, the latter variant requires an understanding of the		semantics of the sensor data, the latter variant requires an
	current sensor levels. In any case, it is important that end hosts		understanding of the current sensor levels. In any case, it is
	are informed about the filtering so that they can distinguish between		important that end hosts are informed about the filtering so that
	data loss and data filtered out on purpose.		they can distinguish between data loss and data filtered out on
			purpose.
	In practice, the collected data is further processed using various		In practice, the collected data is further processed using various
	forms of computation. Some of them are very complex or need the		forms of computation. Some of them are very complex or need the
	complete sensor data during the computation, but there are also		complete sensor data during the computation, but there are also
	simpler operations that can already be done on subsets of the overall		simpler operations that can already be done on subsets of the overall
	dataset or earlier on the communication path as soon as all data is		dataset or earlier on the communication path as soon as all data is
	available. One example is finding the maximum of all sensor values,		available. One example is finding the maximum of all sensor values,
	which can either be done iteratively at each intermediate hop or at		which can either be done iteratively at each intermediate hop or at
	the first hop where all data is available. Using expert knowledge		the first hop where all data is available. Using expert knowledge
	about the exact computation steps and the concrete transmission path		about the exact computation steps and the concrete transmission path
	skipping to change at line 1163 ¶		skipping to change at line 1164 ¶
	context of general stream processing systems.		context of general stream processing systems.
	* RQ 4.2.1: How can the overall data processing pipeline be divided		* RQ 4.2.1: How can the overall data processing pipeline be divided
	into individual processing steps that could then be deployed as		into individual processing steps that could then be deployed as
	COIN functionality?		COIN functionality?
	* RQ 4.2.2: How to design COIN programs for (semantic) packet		* RQ 4.2.2: How to design COIN programs for (semantic) packet
	filtering and which filtering criteria make sense?		filtering and which filtering criteria make sense?
	* RQ 4.2.3: Which kinds of COIN programs can be leveraged for		* RQ 4.2.3: Which kinds of COIN programs can be leveraged for
	(pre)processing steps and what complexity can they have?		preprocessing and processing steps and what complexity can they
			have?
	* RQ 4.2.4: How to distribute and coordinate COIN programs?		* RQ 4.2.4: How to distribute and coordinate COIN programs?
	* RQ 4.2.5: How to dynamically reconfigure and recompose COIN		* RQ 4.2.5: How to dynamically reconfigure and recompose COIN
	programs?		programs?
	* RQ 4.2.6: How to incorporate the (pre)processing and filtering		* RQ 4.2.6: How to incorporate the preprocessing, processing, and
	steps into the overall system?		filtering steps into the overall system?
	* RQ 4.2.7: How can changes to the data by COIN programs be signaled		* RQ 4.2.7: How can changes to the data by COIN programs be signaled
	to the end hosts?		to the end hosts?
	4.2.6. Additional Desirable Capabilities		4.2.6. Additional Desirable Capabilities
	In addition to the capabilities driven by the research questions		In addition to the capabilities driven by the research questions
	above, there are a number of other features that such large-volume		above, there are a number of other features that such large-volume
	applications could benefit from. In particular, conforming to		applications could benefit from. In particular, conforming to
	standard application-level syntax and semantics likely simplifies		standard application-level syntax and semantics likely simplifies
	skipping to change at line 1596 ¶		skipping to change at line 1598 ¶
	network programming of individual virtual switches. To our		network programming of individual virtual switches. To our
	knowledge, no complete solution has been developed for deploying		knowledge, no complete solution has been developed for deploying
	virtual COIN programs over mobile or data center networks.		virtual COIN programs over mobile or data center networks.
	5.3.4. Opportunities		5.3.4. Opportunities
	Virtual network programming by tenants could bring benefits such as:		Virtual network programming by tenants could bring benefits such as:
	* A unified programming model, which can facilitate porting COIN		* A unified programming model, which can facilitate porting COIN
	programs between data centers, 5G networks, and other fixed and		programs between data centers, 5G networks, and other fixed and
	wireless networks, as well as sharing controller, code and		wireless networks, as well as sharing controllers, code, and
	expertise.		expertise.
	* Increasing the level of customization available to customers/		* Increasing the level of customization available to customers/
	tenants of mobile networks or data centers compared to typical		tenants of mobile networks or data centers compared to typical
	configuration capabilities. For example, 5G network evolution		configuration capabilities. For example, 5G network evolution
	points to an ever-increasing specialization and customization of		points to an ever-increasing specialization and customization of
	private mobile networks, which could be handled by tenants using a		private mobile networks, which could be handled by tenants using a
	programming model similar to P4.		programming model similar to P4.
	* Using network programs to influence underlying network services		* Using network programs to influence underlying network services
	skipping to change at line 1869 ¶		skipping to change at line 1871 ¶
	systems typically work on unencrypted data and often customize packet		systems typically work on unencrypted data and often customize packet
	payload, while concepts such as homomorphic encryption could serve as		payload, while concepts such as homomorphic encryption could serve as
	workarounds, allowing PNDs to perform simple operations on the		workarounds, allowing PNDs to perform simple operations on the
	encrypted data without having access to it. All these approaches		encrypted data without having access to it. All these approaches
	introduce the same or very similar security implications as any		introduce the same or very similar security implications as any
	middlebox operating on unencrypted traffic or having access to		middlebox operating on unencrypted traffic or having access to
	encryption: a middlebox can itself have malicious intentions (e.g.,		encryption: a middlebox can itself have malicious intentions (e.g.,
	because it got compromised or the deployment of functionality offers		because it got compromised or the deployment of functionality offers
	new attack vectors to outsiders).		new attack vectors to outsiders).
	However, similar to middlebox deployments, risks for privacy and data		However, similar to middlebox deployments, risks for privacy and the
	exposure have to be carefully considered in the context of the		risk of data exposure have to be carefully considered in the context
	concrete deployment. For example, exposing data to an external		of the concrete deployment. For example, exposing data to an
	operator for mobile application offloading leads to a significant		external operator for mobile application offloading leads to a
	privacy loss of the user in any case. In contrast, such privacy		significant privacy loss of the user in any case. In contrast, such
	considerations are not as relevant for COIN systems where all		privacy considerations are not as relevant for COIN systems where all
	involved entities are under the same control, such as in an		involved entities are under the same control, such as in an
	industrial context. Here, exposed data and functionality can instead		industrial context. Here, exposed data and functionality can instead
	lead to stolen business secrets or the enabling of DoS attacks, for		lead to stolen business secrets or the enabling of DoS attacks, for
	example. Hence, even in fully controlled scenarios, COIN		example. Hence, even in fully controlled scenarios, COIN
	intermediaries, and middleboxes in general, are ideally operated in a		intermediaries, and middleboxes in general, are ideally operated in a
	least-privilege mode, where they have exactly those permissions to		least-privilege mode, where they have exactly those permissions to
	read and alter payload that are necessary to fulfill their purpose.		read and alter payload that are necessary to fulfill their purpose.
	Research on granting middleboxes access to secured traffic is only in		Research on granting middleboxes access to secured traffic is only in
	its infancy, and a variety of different approaches are proposed and		its infancy, and a variety of different approaches are proposed and
	skipping to change at line 1915 ¶		skipping to change at line 1917 ¶
	process. Moreover, such deployments can become central entities		process. Moreover, such deployments can become central entities
	that, if paralyzed (e.g., through extensive requests), can be		that, if paralyzed (e.g., through extensive requests), can be
	responsible for large-scale outages. In particular, some deployments		responsible for large-scale outages. In particular, some deployments
	could be used to amplify DoS attacks. Similar to other middlebox		could be used to amplify DoS attacks. Similar to other middlebox
	deployments, these potential risks must be considered when deploying		deployments, these potential risks must be considered when deploying
	COIN functionality and may influence the selection of suitable		COIN functionality and may influence the selection of suitable
	security protocols.		security protocols.
	Additional system-level security considerations may arise from		Additional system-level security considerations may arise from
	regulatory requirements imposed on COIN systems overall, stemming		regulatory requirements imposed on COIN systems overall, stemming
	from regulation regarding, lawful interception, data localization, or		from regulation regarding lawful interception, data localization, or
	AI use, for example. These requirements may impact, for example, the		AI use, for example. These requirements may impact, for example, the
	manner in which (COIN) programs may be placed or executed in the		manner in which (COIN) programs may be placed or executed in the
	overall system, who can invoke certain (COIN) programs in what PND or		overall system, who can invoke certain (COIN) programs in what PND or
	COIN device, and what type of (COIN) program can be run. These		COIN device, and what type of (COIN) program can be run. These
	considerations will impact the design of the possible implementing		considerations will impact the design of the possible implementing
	protocols but also the policies that govern the execution of (COIN)		protocols but also the policies that govern the execution of (COIN)
	programs.		programs.
	9. IANA Considerations		9. IANA Considerations
	skipping to change at line 2129 ¶		skipping to change at line 2131 ¶
	[RÜTH] Rüth, J., Glebke, R., Wehrle, K., Causevic, V., and S.		[RÜTH] Rüth, J., Glebke, R., Wehrle, K., Causevic, V., and S.
	Hirche, "Towards In-Network Industrial Feedback Control",		Hirche, "Towards In-Network Industrial Feedback Control",
	Proceedings of the 2018 Morning Workshop on In-Network		Proceedings of the 2018 Morning Workshop on In-Network
	Computing, pp. 14-19, DOI 10.1145/3229591.3229592, August		Computing, pp. 14-19, DOI 10.1145/3229591.3229592, August
	2018, <https://doi.org/10.1145/3229591.3229592>.		2018, <https://doi.org/10.1145/3229591.3229592>.
	[SA2-5GLAN]		[SA2-5GLAN]
	3GPP-5glan, "SP-181129, Work Item Description,		3GPP-5glan, "SP-181129, Work Item Description,
	Vertical_LAN(SA2), 5GS Enhanced Support of Vertical and		Vertical_LAN(SA2), 5GS Enhanced Support of Vertical and
	LAN Services", 3GPP , 2021,		LAN Services", 3GPP , 2021,
	<http://www.3gpp.org/ftp/tsg_sa/TSG_SA/Docs/SP-		<https://www.3gpp.org/ftp/tsg_sa/TSG_SA/TSGS_82/Docs/SP-
	181120.zip>.		181120.zip>.
	[SarNet2021]		[SarNet2021]
	Glebke, R., Trossen, D., Kunze, I., Lou, D., Ruth, J.,		Glebke, R., Trossen, D., Kunze, I., Lou, D., Ruth, J.,
	Stoffers, M., and K. Wehrle, "Service-based Forwarding via		Stoffers, M., and K. Wehrle, "Service-based Forwarding via
	Programmable Dataplanes", 2021 IEEE 22nd International		Programmable Dataplanes", 2021 IEEE 22nd International
	Conference on High Performance Switching and Routing		Conference on High Performance Switching and Routing
	(HPSR), pp. 1-8, DOI 10.1109/hpsr52026.2021.9481814, June		(HPSR), pp. 1-8, DOI 10.1109/hpsr52026.2021.9481814, June
	2021, <https://doi.org/10.1109/hpsr52026.2021.9481814>.		2021, <https://doi.org/10.1109/hpsr52026.2021.9481814>.
	skipping to change at line 2159 ¶		skipping to change at line 2161 ¶
	Rodriguez, P., and P. Steenkiste, "Multi-Context TLS		Rodriguez, P., and P. Steenkiste, "Multi-Context TLS
	(mcTLS): Enabling Secure In-Network Functionality in TLS",		(mcTLS): Enabling Secure In-Network Functionality in TLS",
	ACM SIGCOMM Computer Communication Review, vol. 45, no. 4,		ACM SIGCOMM Computer Communication Review, vol. 45, no. 4,
	pp. 199-212, DOI 10.1145/2829988.2787482, August 2015,		pp. 199-212, DOI 10.1145/2829988.2787482, August 2015,
	<https://doi.org/10.1145/2829988.2787482>.		<https://doi.org/10.1145/2829988.2787482>.
	[Stoyanov] Stoyanov, R. and N. Zilberman, "MTPSA: Multi-Tenant		[Stoyanov] Stoyanov, R. and N. Zilberman, "MTPSA: Multi-Tenant
	Programmable Switches", Proceedings of the 3rd P4 Workshop		Programmable Switches", Proceedings of the 3rd P4 Workshop
	in Europe, pp. 43-48, DOI 10.1145/3426744.3431329,		in Europe, pp. 43-48, DOI 10.1145/3426744.3431329,
	December 2020,		December 2020,
	<https://eng.ox.ac.uk/media/6354/stoyanov2020mtpsa.pdf>.		<https://dl.acm.org/doi/10.1145/3426744.3431329>.
	[Sultana] Sultana, N., Sonchack, J., Giesen, H., Pedisich, I., Han,		[Sultana] Sultana, N., Sonchack, J., Giesen, H., Pedisich, I., Han,
	Z., Shyamkumar, N., Burad, S., DeHon, A., and B. T. Loo,		Z., Shyamkumar, N., Burad, S., DeHon, A., and B. T. Loo,
	"Flightplan: Dataplane Disaggregation and Placement for P4		"Flightplan: Dataplane Disaggregation and Placement for P4
	Programs",		Programs",
	<https://flightplan.cis.upenn.edu/flightplan.pdf>.		<https://flightplan.cis.upenn.edu/flightplan.pdf>.
			[TIRPITZ-REDUCIO]
			Tirpitz, L., Kunze, I., Niemietz, P., Gerhardus, A. K.,
			Bergs, T., Wehrle, K., and S. Geisler, "Reducio: Data
			Aggregation and Stability Detection for Industrial
			Processes Using In-Network Computing", DEBS '25:
			Proceedings of the 19th ACM International Conference on
			Distributed and Event-based Systems, pp. 98-109,
			DOI 10.1145/3701717.3730547, June 2025,
			<https://doi.org/10.1145/3701717.3730547>.
	[TLSSURVEY]		[TLSSURVEY]
	de Carné de Carnavalet, X. and P. van Oorschot, "A Survey		de Carné de Carnavalet, X. and P. van Oorschot, "A Survey
	and Analysis of TLS Interception Mechanisms and		and Analysis of TLS Interception Mechanisms and
	Motivations: Exploring how end-to-end TLS is made 'end-to-		Motivations: Exploring how end-to-end TLS is made 'end-to-
	me' for web traffic", ACM Computing Surveys, vol. 55, no.		me' for web traffic", ACM Computing Surveys, vol. 55, no.
	13s, pp. 1-40, DOI 10.1145/3580522, July 2023,		13s, pp. 1-40, DOI 10.1145/3580522, July 2023,
	<https://doi.org/10.1145/3580522>.		<https://doi.org/10.1145/3580522>.
	[TOSCA] Rutkowski, M., Ed., Lauwers, C., Ed., Noshpitz, C., Ed.,		[TOSCA] Rutkowski, M., Ed., Lauwers, C., Ed., Noshpitz, C., Ed.,
	and C. Curescu, Ed., "TOSCA Simple Profile in YAML Version		and C. Curescu, Ed., "TOSCA Simple Profile in YAML Version
	skipping to change at line 2242 ¶		skipping to change at line 2254 ¶
	Email: kunze@comsys.rwth-aachen.de		Email: kunze@comsys.rwth-aachen.de
	Klaus Wehrle		Klaus Wehrle
	RWTH Aachen University		RWTH Aachen University
	Ahornstr. 55		Ahornstr. 55
	D-52074 Aachen		D-52074 Aachen
	Germany		Germany
	Email: wehrle@comsys.rwth-aachen.de		Email: wehrle@comsys.rwth-aachen.de
	Dirk Trossen		Dirk Trossen
	Huawei Technologies Duesseldorf GmbH		DaPaDOT Tech UG (haftungsbeschränkt)
	Riesstr. 25C		Palestrinastr. 7A
	D-80992 Munich		D-80639 Munich
	Germany		Germany
	Email: Dirk.Trossen@Huawei.com		Email: dirk@dapadot-tech.eu
	Marie-Jose Montpetit		Marie-Jose Montpetit
	McGill University		SLICES-RI
	680 Sherbrooke Street W.		Paris
	Montreal H3A 3R1		France
	Canada		Email: marie-jose.montpetit@slices-ri.eu
	Email: marie-jose.montpetit@mcgill.ca
	Xavier de Foy		Xavier de Foy
	InterDigital Communications, LLC		InterDigital Communications, LLC
	1000 Sherbrooke West		1000 Sherbrooke West
	Montreal H3A 3G4		Montreal H3A 3G4
	Canada		Canada
	Email: xavier.defoy@interdigital.com		Email: xavier.defoy@interdigital.com
	David Griffin		David Griffin
	University College London		University College London
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