draft-various-eimpact-arch-considerations.md		draft-various-eimpact-arch-considerations-welzl.md
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	protocol and system design. Further work in detailing this guidance		protocol and system design. Further work in detailing this guidance
	would also be useful.		would also be useful.
	It is likely that there is increased attention to resiliency in the		It is likely that there is increased attention to resiliency in the
	future, given for instance the increased importance of the tasks		future, given for instance the increased importance of the tasks
	supported by networks or the potentially increasing frequency of		supported by networks or the potentially increasing frequency of
	natural disasters as a result of global warming.		natural disasters as a result of global warming.
	## Transport {#transport}		## Transport {#transport}
	Transport protocols are the flexible tools that make it possible for		Transport protocols make it possible for
	communication flows between parties to adjust themselves to the		communication flows to adjust themselves to the
	dynamic conditions that exist in the network at any given time:		dynamic conditions that exist in the network at any given time:
	available bandwidth, delays, congestion, the ability of a peer to send		available bandwidth, delays, congestion, the ability of a peer to send
	or receive traffic, and so on. Depending on the conditions, an		or receive traffic, and so on. Depending on the conditions, an
	individual flow may carry traffic at widely different rates, may pause		individual flow may carry traffic at widely different rates, may pause
	for some time, etc. Various higher-level transport solutions may also		for some time, etc. Various higher-level transport solutions may also
	cache or pre-fetch information.		cache or pre-fetch information.
	This behavior has an effect on sustainability as well, e.g., in		This behavior has an effect on sustainability---e.g., in
	what periods the endpoint and network systems are active or when they		what periods the endpoint and network systems are active or when they
	could be in reduced activity or sleep states.		could be in reduced activity or sleep states.
	Cellular networks and mobile links can scale their energy usage based on load and enter a low-power state when a traffic flow ends. Thus, in theory, the faster the data is transferred, the faster the device transmission/reception functions can enter a low-power state.		Cellular networks and mobile links can scale their energy usage based on load and enter a low-power state when a traffic flow ends. Thus, in theory, the faster the data is transferred, the faster the device transmission/reception functions can enter a low-power state.
	### Motivation		### Motivation
	Transport behavior would have a possibility of impacting how much		Transport behavior would have a possibility of impacting how much
	downtime or sleep can be had in the communication system, either on		downtime or sleep can be had in the communication system, either on
	the end systems or routers or other equipment in between. The savings		the end systems or routers or other equipment in between. The savings
	can be significant, at least in wireless systems.		can be significant, at least in wireless systems.
	Improvements through transport behavior are only useful if the		Improvements through transport behavior are only useful if the
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	can be significant, at least in wireless systems.		can be significant, at least in wireless systems.
	Improvements through transport behavior are only useful if the		Improvements through transport behavior are only useful if the
	involved systems have power proportionality.		involved systems have power proportionality.
	### Analysis		### Analysis
	A critical issue is the tradeoff involved in sending traffic. As		A critical issue is the tradeoff involved in sending traffic. As
	argued in {{NotTradeOff}}, reducing		argued in {{NotTradeOff}}, reducing
	the amount of time the endpoints and the network are active can		the amount of time the endpoints and the network are active can
	sometimes help save energy, e.g. in case the receiver is connected		sometimes help save energy. As a result, in general, delivering information as rapidly as possible would appear to be desirable.
	over a WiFi link. Similar logic applies for any technology that has a
	certain degree of energy proportionality, e.g. cellular
	communication. As a result, in general, delivering information as
	rapidly as possible would appear to be desirable.
	On the other hand, bandwidth-intensive applications can influence		On the other hand, bandwidth-intensive applications can influence
	other applications or users by presenting a significant load on the		other applications or users by presenting a significant load on the
	network, and consequently reducing capacity available for others, or		network, and consequently reducing capacity available for others, or
	increasing buffering (and with it, latency) across the network		increasing buffering (and with it, latency) across the network
	path. For an application with intermittent data transfers, such as		path. For an application with intermittent data transfers, such as
	streaming video, this would seem to speak in favor of sustained but		streaming video, this would seem to speak in favor of sustained but
	lower-rate delivery instead of transmitting short high-rate bursts {{Sammy}}. However, this		lower-rate delivery instead of transmitting short high-rate bursts {{Sammy}}. However, this
	is in contradiction with the energy-saving approach above. Thus, the		is in contradiction with the energy-saving approach above. Thus, the
	tradeoff is: should data be sent in a way that is "friendly" to others		tradeoff is: should data be sent in a way that is "friendly" to others
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	of other traffic. For non-urgent data transfers, the IETF-recommended		of other traffic. For non-urgent data transfers, the IETF-recommended
	default approach is the opposite: the LEDBAT congestion control		default approach is the opposite: the LEDBAT congestion control
	mechanism {{RFC6817}}, which is designed for such use, will always		mechanism {{RFC6817}}, which is designed for such use, will always
	"step out of the way" of other traffic, giving it a low rate when it		"step out of the way" of other traffic, giving it a low rate when it
	competes with any other traffic. Alternatively, if the goal is to		competes with any other traffic. Alternatively, if the goal is to
	reduce energy, such traffic could be sent at a high rate, at a		reduce energy, such traffic could be sent at a high rate, at a
	strategically good moment within a longer time interval; this would		strategically good moment within a longer time interval; this would
	give network equipment an opportunity to enter a sleep state in the		give network equipment an opportunity to enter a sleep state in the
	remaining time period within the interval.		remaining time period within the interval.
	Perhaps the issue is that the transport behavior (as with many other		Perhaps transport protocols should, in the future,
	things) needs to take into account multiple parameters. For example,		take energy into account in addition to the many other inputs they decide upon. For example, it is possible that a non-urgent data transfer would send as much as possible as soon as possible when
	it is possible that a balanced transport algorithm would be able to		at least one of the links along the path is known to be power proportional (e.g., a cellular link), while tracking buffer
	send as much as possible as soon as possible, while tracking buffer		growth from transmission delays to scale back if delay should occur. Such ideas remain to be confirmed with experiments, however.
	growth from transmission delays and scaling back if there's any buffer
	growth. This remains to be confirmed with experiments, however.
	Similarly, caching and pre-fetching designs need to take into account		Similarly, caching and pre-fetching designs need to take into account
	not only the likelihood of having acquired the right content in memory,		not only the likelihood of having acquired the right content in memory,
	but also the sustainability cost of possibly fetching too much or the		but also the sustainability cost of possibly fetching too much or the
	timing of those fetching operations.		timing of those fetching operations.
	In general, information about the impacts of loading or not loading		In general, information about the impacts of loading or not loading
	the network with additional traffic, and whether a certain sending		the network with additional traffic, and whether a certain sending
	pattern enables power savings through sleep modes, would be beneficial		pattern enables power savings through sleep modes, would be beneficial
	for the communicating endpoints. Mechanisms for making such		for the communicating endpoints. Mechanisms for making such
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