An Overview of Energy-related Effort within the IETF
draft-eckert-ietf-and-energy-overview-04
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draft-eckert-ietf-and-energy-overview-04
Network Working Group T. Eckert, Ed.
Internet-Draft Futurewei Technologies USA
Intended status: Informational M. Boucadair, Ed.
Expires: 13 September 2023 Orange
P. Thubert
Cisco Systems, Inc.
J. Tentsura
NVIDIA
12 March 2023
An Overview of Energy-related Effort within the IETF
draft-eckert-ietf-and-energy-overview-04
Abstract
This memo provides an overview of work performed by or proposed
within the IETF related to energy and/or green: awareness,
management, control or reduction of consumption of energy, and
sustainability as it related to the IETF.
This document is written to help those unfamiliar with that work, but
interested in it, in the hope to raise more interest in energy-
related activities within the IETF, such as identifying gaps and
investigating solutions as appropriate.
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 13 September 2023.
Copyright Notice
Copyright (c) 2023 IETF Trust and the persons identified as the
document authors. All rights reserved.
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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 . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Energy Saving: An Introduction . . . . . . . . . . . . . . . 3
2.1. Digitization . . . . . . . . . . . . . . . . . . . . . . 4
2.2. Energy Saving Through Scale . . . . . . . . . . . . . . . 4
2.2.1. An Iconic Example: Telephony . . . . . . . . . . . . 5
2.2.2. The Packet Multiplexing Principle . . . . . . . . . . 5
2.2.3. End-to-End Transport . . . . . . . . . . . . . . . . 5
2.2.4. Global vs Restricted Connectivity: The Internet Routing
Architectures . . . . . . . . . . . . . . . . . . . . 5
2.2.5. Freedom to Innovate . . . . . . . . . . . . . . . . . 6
2.2.6. End-to-End Encryption . . . . . . . . . . . . . . . . 6
2.2.7. Converged Networks . . . . . . . . . . . . . . . . . 6
2.2.7.1. IntServ and DetNet . . . . . . . . . . . . . . . 7
2.2.7.2. DiffServ . . . . . . . . . . . . . . . . . . . . 7
2.2.7.3. SIP . . . . . . . . . . . . . . . . . . . . . . . 7
3. Higher or New Energy Consumption . . . . . . . . . . . . . . 8
4. Some Notes on Sustainability . . . . . . . . . . . . . . . . 9
4.1. Follow the Energy Cloud Scheduling . . . . . . . . . . . 9
4.2. Optimize Generated Heat . . . . . . . . . . . . . . . . . 10
4.3. Heat Recovery . . . . . . . . . . . . . . . . . . . . . . 10
4.4. Telecollaboration . . . . . . . . . . . . . . . . . . . . 10
5. Energy Optimization in Specific Networks . . . . . . . . . . 12
5.1. Low Power and Lossy Networks (LLN) . . . . . . . . . . . 12
5.1.1. 6LOWPAN WG . . . . . . . . . . . . . . . . . . . . . 13
5.1.2. LPWAN WG . . . . . . . . . . . . . . . . . . . . . . 13
5.1.3. 6TISCH WG . . . . . . . . . . . . . . . . . . . . . . 13
5.1.4. 6LO WG . . . . . . . . . . . . . . . . . . . . . . . 13
5.1.5. ROLL WG . . . . . . . . . . . . . . . . . . . . . . . 13
5.2. Constrained Nodes and Networks . . . . . . . . . . . . . 15
5.2.1. LWIG WG . . . . . . . . . . . . . . . . . . . . . . . 15
5.2.2. CoRE and CoAP . . . . . . . . . . . . . . . . . . . . 15
5.2.3. Satellite Constellations . . . . . . . . . . . . . . 16
5.2.4. Devices with Batteries . . . . . . . . . . . . . . . 16
5.3. Sample Technical Enablers . . . . . . . . . . . . . . . . 16
5.3.1. (IP) Multicast . . . . . . . . . . . . . . . . . . . 16
5.3.1.1. Power Saving with Multicast . . . . . . . . . . . 16
5.3.1.2. Power Waste Through Multicast-based Service
Coordination . . . . . . . . . . . . . . . . . . . 17
5.3.1.3. Multicast Problems in Wireless Networks . . . . . 18
5.3.2. Sleepy Nodes . . . . . . . . . . . . . . . . . . . . 19
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5.4. (Lack of) Power Benchmarking Proposals . . . . . . . . . 20
6. Energy Management Networks . . . . . . . . . . . . . . . . . 21
6.1. Smart Grid . . . . . . . . . . . . . . . . . . . . . . . 21
6.2. Syncro Phasor Networks . . . . . . . . . . . . . . . . . 21
7. (Limited) Energy Management for Networks . . . . . . . . . . 22
7.1. Some Metrics . . . . . . . . . . . . . . . . . . . . . . 22
7.2. EMAN WG . . . . . . . . . . . . . . . . . . . . . . . . . 23
8. Power-Awareness in Forwarding and Routing Protocols . . . . . 25
8.1. Power Aware Networks (PANET) . . . . . . . . . . . . . . 25
8.2. SDN-based Semantic Forwarding . . . . . . . . . . . . . . 26
8.3. Misc . . . . . . . . . . . . . . . . . . . . . . . . . . 26
9. Gaps . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 27
11. Changelog . . . . . . . . . . . . . . . . . . . . . . . . . . 27
12. Informative References . . . . . . . . . . . . . . . . . . . 28
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 41
1. Introduction
This document summarizes work that has been proposed to or performed
within the IETF/IRTF. Particularly, it covers IETF/IRTF RFCs as well
as ISE RFCs and IETF/IRTF or individual submission drafts that where
abandoned for various reasons (e.g., lack of momentum, broad scope).
There are various aspects how a given work relates to energy that are
classified into categories. Such a classification does not attempt
to propose a formal taxonomy, but is used for the sake of better
readability. Technologies are listed under a category that is
specifically significant, for example, by being most narrow.
This memo usually refers to the technologies by significant early RFC
or specific draft version, as opposed to the newest. This is
contrary to the common practice in IETF documents to refer to the
newest version. This appraoch is meant to allow readers to better
understand the historic timeline in which a specific technology was
proposed or introduced. Especially successful IETF technologies will
have newer RFC that updates such initial work.
2. Energy Saving: An Introduction
Technologies that simply save energy compared to earlier or other
alternatives are the broadest and most unspecific category. In this
memo such an energy saving simply refers to energy savings in some
unit of electricity, such as kWh and does not take other aspects of
energy optimization into account. See Section 4 for more details.
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2.1. Digitization
Digitization describes the transformation of processes from non- or
less digital with networking to more digital with computer-
networking. For comparable process results, the digitized option is
often, but not always, less energy-consuming. Consider, for example,
the energy consumption in the evolution of messaging starting from
postal mail and overs telegrams and various other historic form to
solutions including e-mail utilizing, for example, the IETF "Simple
Mail Transport Protocol" (SMTP, [RFC822] obsoleted by [RFC2822],
[RFC5322]), group communications utilizing the IETF "Network News
Transport Protocol" (NNTP, [RFC3977]) or the almost infinite set of
communication options built on top of the IETF "HyperText Transport
Protocol" (HTTP, [RFC2086] and successors), and IETF "HyperText
Markup Language" (HTML, [RFC1866] uperceeded by various later version
of HTML, see [RFC2854]).
Conventionally, digitization had only "incidental", but not
"intentional" relationship to energy consumption: If it saved energy,
this was not only not a target benefit, it was not even recognized as
one, until probably recently. Instead, the evolution was driven from
anything-but-energy benefits, but instead utility benefits such as
improved speed, functionality/flexibility, accessibility, usability,
scalability, and reduced cost.
In hindsight though, digitization through IETF technologies and
specifically the Internet will likely have the largest contribution
to energy saving amongst all the possible categories, but it is also
the hardest to pinpoint on any specific technology/RFC. Instead, it
is often a combination of the whole stack of deployed protocols and
operational practices that contributes to energy saving through
digitization. It is likely also the biggest overall energy saving
impact of all possible categories that relate IETF work to energy:
The Internet as well as all other IP/MPLS networks are likely the
biggest energy saving development of the past few decades if only the
energy consumption of equivalent services is compared. On the other
hand, they are also the cause for the biggest new type of new energy
consumption because of all the new services introduced in the past
decades with the Internet and the hyper-scaling that the Internet
affords them.
2.2. Energy Saving Through Scale
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2.2.1. An Iconic Example: Telephony
In most cases, energy saving through the use of IETF protocols
compared to earlier (digitized or non digitized) solutions is purely
a result of the reduction in the energy cost per bit over the decades
in networking. For example, the energy consumption of digital voice
telephony through the IETF "Session Initiation Protocol" (SIP,
[RFC2543] superceeded by [RFC3261] and successors) can easily be
assumed to be more energy efficient on a per voice-minute basis than
prior voice technologies such as analog or digital "Time Division
Multiplex" (TDM) telephony solely because of this evolution in mostly
device as well as physical-layer and link-layer networking
technologies.
2.2.2. The Packet Multiplexing Principle
Nevertheless, it is at the heart of the packet multiplexing model
employed by the IETF networking protocols IP ([RFC791]) and IPv6
([RFC1883] superceeded by [RFC2460] and [RFC8200]) to successfully
support this scaling that brough down the cost per bit through ever
faster links and network nodes, especially for networks larger than
building scale networks. While the IETF protocols have not been the
first or over their early decades necessarily the most widely
deployed packet networking protocols, they where the ones who at
least during the 1990s started to break away from other protocols
both in scale of deployment, as well as in development of further
technologies to support this scaling.
2.2.3. End-to-End Transport
At the core of scalability, even up to now, is the lightweight per-
packet-processing enabled through end-to-end congestion loss
management architecture as embodied through the IETF "Transmission
Control Protocol" (TCP, [RFC793] and successors, e.g.
[I-D.ietf-tcpm-rfc793bis]). This model eliminated more expensive
per-hop, per-packet processing, such as would be required for
reliable hop-by-hop forwarding through per-hop ARQ, which was key to
scaling routers cost effectively.
2.2.4. Global vs Restricted Connectivity: The Internet Routing
Architectures
The meshed peer-to-peer and transitive routing of the Internet
enabled through the IETF Border Gateway (Routing) Protocol (BGP,
[RFC4271] as well as predecessors) is another key factor to
successful scalability, because it enabled competitive market forces
to explore markets quickly.
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Prior to the Internet, the public often only had access to highly
regulated international networking connections through often per-
country monopoly regulated data networks.
2.2.5. Freedom to Innovate
(non-IP) networks often also did not allow as much "freedom-to-
innovate" (as it is often called in the IETF) for applications
running over it. Instead those networks where exploring the coupling
of packet transport with higher layer services to allow the network
operator some degree of revenue sharing with the services running on
top of it. Such approaches resulted not only in higher cost of those
services but also (likely) preferential and (often) exclusionary
treatment of network traffic not fitting the perceived highest
revenue service options.
2.2.6. End-to-End Encryption
When the same business practices where applied to IP network, it was
one of the key factors leading to the development of IETF end-to-end
encryption though protocols such as "Transport Layer Security" (TLS,
[RFC2246] [RFC4346], [RFC5246], [RFC8446]). This further
strengthened the ability to scale service/applications at minimum
additional cost for the underlying packet transport, arguably driving
innovation into ever faster networking technology and likely lower
cost per bit.
2.2.7. Converged Networks
Another key factor to support scaling where IETF technologies that
allowed to multiplex different types of traffic (e.g., realtime vs.
non-realtime) which previously used separate networks with typically
incompatible networking technologies.
Eliminating multiple physical networks with separate routing/
forwarding nodes and separate links affords significant energy
savings even at the same generation of speed and hence energy/bit
simply by avoiding the N-fold production and operations of equipment
and links. Of course, originally the CAPEX and OPEX of multiple,
technology-diverse networks and host-stacks was the core reason for
unified networks, and energy saving is in hindsight just incidental
(as for all other cases mentioned here).
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2.2.7.1. IntServ and DetNet
The first (non-IETF) wider adopted technology promising converged
networks was "Asynchronuous Transfer Mode" (ATM), which was designed
and deployed at the end of the 1980s to support specifically
multiplexing of "Data Voice and Video", where both Voice and Video
(at that time) required loss-free deterministic bounded latency and
low-jitter and had therefore their own Time-Division-Multiplex (TDM)
networks, both separate from so-called Data networks using packet
multiplexing. This technology was very expensive on a per-bit basis
due to its cell-forwarding nature though.
At the end of the 1980s, it was proven in [BOUNDED_LATENCY] that
variable length packet multiplexing in network can also support non-
NP-hard calculations for bounded latency. This lead to the IETF
"Integrated Services WG" (INTSERV) to support such guaranteed
throughput and bounded latency traffic via [RFC2212] - and to the
demise of ATM.
IntServ has so far seen little traction because it too got
superceeded as explained in the following section - for its original
use-cases (voice and video). However this type of services are being
revisited for a broader set of use-cases [RFC8575] in the DetNet WG,
which should enable even further network infrastructure convergence
for IoT and industrial markets.
2.2.7.2. DiffServ
Due to the much higher per-packet processing overhead of INTSERV
versus standard (so-called Best-Effort) Internet traffic, the INTSERV
model was already recognized in the 1990s to not support highest-
scale at lowest cost, leading to the parallel development of the IETF
"Differentiated Services WG" (DIFFSERV) model defined in [RFC2475].
This has since then become the dominant technology to support
multiplexing of applications and services originally not designed for
the Internet onto a common TCP/IP network infrastructure,
specifically for voice and video over UDP ([RFC768]) including RTP
[RFC3550] and SIP.
2.2.7.3. SIP
SIP has most notably in the past two decades eliminated additional
network infrastructures previously required for (voice) telephony
services starting in the early 2000 with commercial/enterprise
deployments and today by removing even the option for any (non-IP/
SIP) analog or digital (ISDN) telephone service connection, instead
delivering those purely as services over adaptation interfaces on
home routers (TBD: Any RFC to cite for those tunneling/adaptation
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services ?).
3. Higher or New Energy Consumption
Digitized, network centric workflows may consume more energy than
their non-digitized counterpart, as may new network centric workflows
without easy to compare prior workflows.
In one type of instances, the energy consumption on a per-instance
basis is lower than in the non-digitized/non-Internet-digitized case,
but the total number of instances that are (Internet)-digitized is
orders of magnitudes larger than their alternative options, typically
because of their higher utility or lower overall cost.
For example, each instance of (simple text) email consumes less
energy than sending a letter or postcard. Even streaming a movie or
TV series consumes less energy than renting a DVD DVDvsStreaming
(https://www.smithsonianmag.com/science-nature/streaming-movie-less-
energy-dvd-180951586). Nevertheless, the total amount of instances
and in result energy consumption for email and streaming easily
outranks their predecessor technologies.
While these instances look beneficial from a simple energy
consumption metric, its overall scale and the resulting energy
consumption may in itself become an issue, especially when the energy
demand it creates risks to outstrip the possible energy production,
short term or long term. This concern is nowadays often raised
against the "digital economy", where the network energy consumption
is typically cited as a small contributor relative to its
applications, such as what is running in Data Centers (DC).
In other cases, the energy consumption of digitization requires often
significantly more than their pre-digitization alternatives. The
most well-known example of this are likely crypto-currencies based on
"proof-of-work" computations (mining), which on a per currency value
unit can cost 10..30 times or more of the energy consumed by for
example gold mining (very much depending on the highly fluctuating
price of the crypto-currency). Nevertheless, its overall utility
compared to such prior currencies or valuables makes it highly
successful in the market.
In general, the digital economy tends to be more energy intensive on
a per utility/value unit, for example by replacing a lot of manual
labor with computation), and/or it allows for faster growth of its
workflows.
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The lower the cost of network traffic, and the more easily accessible
everywhere network connectivity is, the more competitive and/or
successful most of these new workflows of the digital economy can be.
Given how TCP/IP based networks, especially the Internet have
excelled through their design principles (and success) in this
reduction of network traffic cost and ubiquitous access over the past
few decades, as outlined above, one can say that IETF technologies
and especially the Internet are the most important enabler of the
digital economy, and the energy consumption it produces.
4. Some Notes on Sustainability
Sustainability is the principle to utilize resources in a way that
they do not diminish or run out over the long term (e.g., ore
depletion required for building hardware). Beyond the above covered
energy saving, sustainability relates with respect to the IETF
specifically to the use of renewable sources of energy to minimize
exhaustion of fossile resources, and the impact of IETF technologies
on global warming to avoid worsening living conditions on the planet.
While there seems to be no IETF work specifically intending to target
sustainability, the Internet itself can similarly to how it does for
digitization play a key role in building sustainable networked IT
infrastructures. The following subsections list three examples areas
where global high performance, low-cost Internet networking is a key
requirement.
4.1. Follow the Energy Cloud Scheduling
Renewable energy resources (except for water) do commonly have
fluctuating energy output. For example, solar energy output
correlates to night/day and strength of sunlight. Cloud Data Centers
(DC) consume a significant amount of the IT sectors energy. Some
workloads may simply be scheduled to consume energy in accordance
with the amount of available renewable energy at the time, not
requiring the network. Significant workloads are not elastic in
time, such as interactive cloud DC interactive work (cloud based
applications) or entertainment (gaming, etc.). These workloads may
be instantiated or even dynamically (over time) migrate to a DC
location with sufficient renewable energy and the Internet (or large
TCP/IP OTT backbone networks) will serve as the fabric to access the
remote DC and to coordinate the instantiation/migration.
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4.2. Optimize Generated Heat
The majority of energy in cloud DCs is normally also wasted as
exhaust heat, requiring even more energy for cooling. The warmer the
location, the more energy needs to be spent for cooling. For this
reason, DCs in cooler climates, such as https://greenmountain.no/
power-and-cooling/, can help to reduce the overall DC energy
consumption significantly (independent of the energy being consumed
in the DC to be renewable itself). The Internet again plays the role
of providing access to those type of DCs whole location is not
optimized for consumption but for sustainable generation of compute
and storage.
4.3. Heat Recovery
Exhaust heat, especially from compute in DCs, can be recovered when
it is coupled to heating systems ranging in size all the way from
individual familys home through larger buildings (hotels, for
example) all the way to district heating systems. A provider of such
a type of compute-generated heat as a service can sell the compute
capacity as long as there is cost efficient network connectivity.
"Cloud & Heat" is an example company offering such infrastructures
and services https://www.cloudandheat.com/wp-content/
uploads/2020/02/2020_CloudHeat-Whitepaper-Cost-saving-Potential.pdf.
4.4. Telecollaboration
Telecollaboration has a long history in the IETF resulting in
multiple core technologies over the decades.
If one considers textual communications via email and netwnews (using
e.g., NNTP) as early forms of Telecollaboration, then
telecollaboration history through IETF technology reaches back into
the 1980s and earlier.
Around 1990, the IETF work on IP Multicast (e.g. [RFC1112] and
later) enabled the first efficient forms of audio/video group
collaboration through an overlay network over the Internet called the
MBone https://en.wikipedia.org/wiki/Mbone which was also used by the
IETF for more than a decade to provide remote collaboration for its
own (in-person + remote participation) meetings.
With the advent of SIP in the early 2000s, commercial
telecollaboration started to be built most often on SIP based session
and application protocols with multiple IETF working groups
contributing to that protocol suite (TBD: how much more example/
details should we have here). Using this technology and the
Internet, the immersive nature of telecollaboration was brought to
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life-size video, was/is called Telepresence
https://en.wikipedia.org/wiki/Telepresence and later to even more
immersive forms such as AR/VR telecollaboration.
In 2011, the IETF opened the "Real-Time Communication in Web-
browsers" (RTCWEB) WG, that towards the end of that decade became the
most widely supported cross-platform standard for hundreds of
commercial and free tele-collaboration solutions, including Cisco
Webex, which is also used by the IETF itself, Zoom and the new IETF
collaboration suite MeetEcho (TBD: good references here ?).
While the various forms of Telecollaboration are mostly instances of
digitization, they are discussed under sustainability because of its
comparison to in-person travel that is not based on simple comparison
of energy, but nowadays by comparing their impact on global warming,
a key factor to sustainability.
Telecollaboration was primarily developed because of the utility for
the participants - to avoid travel for originally predominantly
business communications/collaborations. It saw an extreme increase
in use (TBD: references) in the Corona Crisis of 2019, when
especially international travel was often prohibited, and often even
working from an office. This forced millions of people to work from
home and utilizing commercial telecollaboration tools. It equally
caused most in-person events that where not cancelled to be moved to
a telecollaboration platform over the Internet - most of them likely
relying on RTCWEB protocols.
Actual energy consumption related comparison between teleconferencing
and in-person travel is complex but since the last decades is
commonly based on calculating some form of CO2 emission equivalent of
the energy consumed, hence comparing not simply the energy
consumption, but weighing it by the impact the energy consumption has
on one of the key factors (CO2 emission) known to impact sustainable
living conditions.
[VC2014] is a good example of a comparison between travel and
telecollaboration taking various factors into account and using CO2
emission equivalents as its core metric. That paper concludes that
carbon/ energy cost of telecollaboration could be as little as 7% of
an in-person meeting. in-person meeting. Those numbers have various
assumptions and change when time-effort of participants is converted
to carbon/energy costs. These numbers should even be better today in
favor of telecollaboration: cost of Internet traffic/bit goes down
while cost of fossile fuel for travel goes up.
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Recently, air travel has also come under more scrutiny because the
greenhouse gas emissions of air travel at the altitudes used by
commercial aviation has been calculated to have a higher global
warming impact than simply the amount of CO2 used by the air plane if
it was exhausted at surface level. One publicly funded organization
offering carbon offset services calculates a factor 3 of the CO2
consumption of an air plane
https://www.atmosfair.de/de/fliegen_und_klima/flugverkehr_und_klima/
klimawirkung_flugverkehr/.
In summary: Telecollaboration has a higher sustainability benefit
compared to travel than just the comparison of energy consumption
because of the higher challenge to use renewable energy in
transportation than in networking, and this is most extreme in the
case of telecollaboration that replaces air travel because of the
even higher global warming impact of using fossile fuels in air
travel.
5. Energy Optimization in Specific Networks
5.1. Low Power and Lossy Networks (LLN)
Low Power and Lossy Networks (LLNs) are networks in which nodes and/
or radio links have constraints. Low power consumption constraints
in nodes often originate from the need to operate nodes from as long
as possible from battery and/or energy harvesting such as (today most
commonly) solar panels associated with the node or ambient energy
such as energy harvesting from movement for wearable nodes or piezo
cells to generate energy for mechanically operated nodes such as
switches.
Several IETF WGs have or are producing work is primarily intended wo
support LLN through multiple layers of the protocol stack. [RFC8352]
gives a good overview of the energy consumption related communication
challenges and solutions produced by the IETF for this space.
To minimize the energy needs for such nodes, their network data-
processing mechanisms have to be optimized. This includes packet
header compression, fragmentation (to avoid latency through large
packets at low bitrates, packet bundling to only consume radio energy
at short time periods, radio energy tuning to just reach the
destination(s), minimization of multicasting to eliminate need of
radio receivers to consume energy and so on. [RFC8352] gives a more
detailed overview, especially because different L2 technologies such
as IEEE 802.15.4 type (low power) wireless networks, Bluetooth Low
Energy (BLE), WiFi (IEEE 802.11) and DEC ULE.
In the INT area of the IETF, several LLN specific WGs exist(ed):
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5.1.1. 6LOWPAN WG
The "IPv6 over Low power WPAN (Wireless Personal Area Networks)"
(6lowpan) WG ran from 2005 to 2014 and produced 6 RFC that adopt IPv6
to IEEE 802.15.4 type (low power) wireless networks by transmission
procedures [RFC4949], compression of IPv6 (and transport) packet
headers [RFC6282], modifications for neighbor discovery (ND)
[RFC6775], as well as 3 informational RFCs about the WPAN space and
applying IPv6 to it. "Transmission of IPv6 Packets over IEEE
802.15.4 Networks" [RFC4944], "Compression Format for IPv6 Datagrams
over IEEE 802.15.4-Based Networks" [RFC6282], "Neighbor Discovery
Optimization for IPv6 over Low-Power Wireless Personal Area Networks
(6LoWPANs)" [RFC6775] (6LOWPAN-ND).
5.1.2. LPWAN WG
Since 2014, the "IPv6 over Low Power Wide-Area Networks" (LPWAN) WG
has produced 4 RFC for low-power wide area networks, such as LoRaWAN
https://en.wikipedia.org/wiki/LoRa, with three standards, [RFC8724],
[RFC8824], [RFC9011].
5.1.3. 6TISCH WG
Since 2013, the "IPv6 over the TSCH mode of IEEE 802.15.4e" (6tisch)
WG has produced 7 RFC for a version of 802.15.4 called the "Time-
Slotted Channel Hopping Mode" (TSCH), which supports deterministic
latency and lower energy consumption through the use of scheduling
traffic into well defined time slots, thereby also optimizing/
minimizing energy consumption when compared to 802.15.4 without TSCH.
5.1.4. 6LO WG
Since 2013, the "IPv6 over Networks of Resource-constrained Nodes"
(6lo) WG has generalized the work of 6lowpan for LLN in general,
producing 17 RFC for IPv6-over-l2foo adaptation layer specifications,
information models, cross-adaptation layer specification (such as
header specifications) and maintenance and informational documents
for other pre-existing IETF work in this space.
5.1.5. ROLL WG
In the RouTinG (RTG) area of the IETF, the "Routing Over Low power
and Lossy networks" (ROLL) WG has produced since 2008 23 RFC.
Initially it produced requirement RFCs of different type of "Low-
power and Lossy Networks": urban: [RFC5548], industrial [RFC5673],
home automation [RFC5826] and building automation [RFC5867].
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Since then its work is mostly focused on the "IPv6 Routing Protocol
for Low-Power and Lossy Networks" (RPL) [RFC6550], which is used in a
wide variety of the above described IPv6 instances of LLN networks
and which are discussed in two ROLL applicability statement RFCs,
"Applicability Statement: The Use of the Routing Protocol for Low-
Power and Lossy Networks (RPL) Protocol Suite in Home Automation and
Building Control" [RFC7733] and "Applicability Statement for the
Routing Protocol for Low-Power and Lossy Networks (RPL) in Advanced
Metering Infrastructure (AMI) Networks" [RFC8036].
The ROLL WG also wrote a more generic RFC for LLN, "Terms Used in
Routing for Low-Power and Lossy Networks" [RFC7102]. RPL has a
highly configurable set of functions to support (energy) constrained
networks. Unconstrained root node(s), typically edge routers between
the RPL network and a backbone network calculate "Destination-
Oriented Directed Acyclic Graphs" (DODAG) and can use strict hop-by-
hop source routing with dedicated IPv6 routing headers [RFC9008] to
minimize constrained nodes routing related compute and memory
requirements. "The Trickle Algorithm" [RFC6206] allows to minimize
routing related packets through automatic lazy updates. While RPL is
naturally a mesh network routing protocol, where all nodes are
usually expected to be able to participate in it, RPL also supports
even more lightweight leave nodes [RFC9010].
The 2013 [I-D.ajunior-energy-awareness-00] proposes the introducing
of energy related parameters into RPL to support calculation/
selection of most energy efficient paths. The 2017 "An energy
optimization routing scheme for LLSs",
[I-D.wang-roll-energy-optimization-scheme] observed that DODAGs in
RPL tend to require more energy in nodes closer to the root and
proposed specific optimizations to reduce this problem. Neither of
these drafts proceeded in the IETF.
While original use-cases for RPL where energy and size limited
networks, its design is to a large extend not scale limited. Because
of this, and due to its reduced compute/memory requirements for the
same size networks compared to other routing protocols, especially
the so-called link-state "Interior Gateway routing Protocols" (IGP),
such as most commonly used protocols ISIS ([RFC1142] superceeded by
[ISO10589-Second-Edition]) and OSPF [RFC2328], RPL has also
proliferated into use-cases for non-constrained networks, for example
to support the largest possible networks automatically, such as in
[RFC8994].
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5.2. Constrained Nodes and Networks
(Power) constrained nodes and/or networks exist in a much broader
variety than coupled with low-power and lossy networks. For example
WiFi and mobile network connections are not considered to be lossy
networks, and personal mobile nodes with either connections are order
of magnitude less constrained than nodes typically attached to LLN
network. Therefore, broader work in the IETF than focused primarily
on LLN typically uses just the term lightweight or constrained (nodes
and networks).
5.2.1. LWIG WG
Since 2013, the "Light-Weight Implementation Guidance" (lwig) WG is
has produced 6 informational RFC on the groups subject, much of which
indirectly supports implementing power efficient network
implementations via lightweight nodes/links, but it also addressed
the topic explicitly including via the aforementioned [RFC8352] and
[RFC9178], "Building Power-Efficient Constrained Application Protocol
(CoAP) Devices for Cellular Networks".
5.2.2. CoRE and CoAP
In the APPlication (APP) area of the IETF, the "Constrained RESTful
Environments" (core) WG has produced since 2010 21 RFC, most of them
for or related to "The Constrained Application Protocol" (CoAP)
[RFC6690], which can best be described as a replacement for HTTP for
constrained environment, using UDP instead of TCP and DTLS instead of
TLS, compact binary message formats instead of human readable textual
formats, RESTful message exchange semantic instead of a broader set
of options (in HTTP), but also more functionality such as (multicast)
discovery and directory services, therefore providing a more
comprehensive set of common application functions with more compact
on-the-wire/radio encoding than its unconstrained alternatives.
"Object Security for Constrained RESTful Environments" (OSCORE),
[RFC8613] is a further product of the CoRE WG providing a more
message layer based, more lightweight security alternative to DTLS.
While originally designed for LLN, CoAP is transcending LLN and
equally becoming standards in unconstrained environments such as
wired/ethernet industrial Machine 2 Machine (M2M) communications,
because of simplicity, flexibility and relying on the single set of
protocols supporting the widest range of deployment scenarios.
In the SECurity (SEC) area of the IETF, the "Authentication and
Authorization for Constrained Environments" (ace) working group has
since 2014 produced 4 RFC for security functions in constrained
environments, for example CoAP based variations of prior HTTPS
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protocols such as EST-coaps [RFC9148] for HTTPS based EST [RFC7030].
Constrained node support in cryptography especially entails support
for Elliptic Curve (EC) public keys due to their shorter key sizes
and lower compute requirements compared to RSA public keys with same
cryptographic strength. While the benefits of EC over RSA where
making them preferred, this "additional market space" (constrained
node) benefit helped in their faster market proliferation even beyond
constrained networks.
5.2.3. Satellite Constellations
Emerging communication infrastructures may have specific requirements
on power consumption. Such requirements should be taken into account
when designing/customizing techniques (e.g., routing) to be enabled
in such networks. For example,
[I-D.lhan-problems-requirements-satellite-net] identifies a set of
requirements (including power) for satellite constellations.
5.2.4. Devices with Batteries
Many IETF protocols (e.g., [RFC3948]) were designed to accommodate
the presence of middleboxes mainly by encouraging clients to issue
frequent keepalives. Such strategy has implication on battery-
supplied devices. In order to optimize battery consumption for such
devices, [RFC6887] specifies a deterministic method so that client
can control state in the network, including their lifetime.
Keepalive alive messages may this be optimized as a function of the
network policies.
A_REC#2 of [RFC7849] further insist on the importance of saving
battery exacerbated by keep-alive messages and recommends the support
of collaborative means to control state in the network rather than
relying on heuristics.
5.3. Sample Technical Enablers
5.3.1. (IP) Multicast
5.3.1.1. Power Saving with Multicast
IP Multicast was introduced with [RFC1112] and today also called "Any
Source Multicast" (ASM) has various protocols standardized in the
IETF across multiple working groups. There are also MPLS and BIER
multicast protocols from the IETF developed in the equally named WGs.
These three, network layer multicast technologies can be a power
saving technologies when used to distribute data because they reduce
the number of packets that need to be sent across the network
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(through in-network-replication where needed). Because most current
link and router technologies do not allow to actually save
significant amounts of energy on lower than maximum utilization,
these benefits are often only theoretical though. Software routers
are the ones most likely to expose energy consumption somewhat
proportional to their throughput for just the forwarding (CPU) chip.
Likewise, in large backbone networks, IP multicast can free up
bandwidth to be used for other traffic, such as unicast traffic,
which may allow to avoid upgrades to faster and potentially more
power consuming routers/links. Today, these benefits too are most
often overcompensated for by lower per-bit energy consumption of
newer generations of routers and links though.
Multicasting can also save energy on the transmitting station across
radio links, compared to replicated unicast traffic, but this is
rarely significant, because except for fully battery powered mesh
network, there are typically non-energy-constrained nodes, such as
(commonly) the wired access-points in WiFi networks.
In result, today multicasting has typically no significant power
saving benefits with available network technologies. Instead it is
used (for data distribution) when the amount of traffic that a
unicast solution alternative (with so-called ingress replication) is
not possible due to the total amount of traffic generated. This
includes wireless/radio networks, where equally airtime is the
limiting factor.
5.3.1.2. Power Waste Through Multicast-based Service Coordination
(IP) multicast is often not used to distribute data requested by
receivers, but also coordination type functions such as service or
resource announcement, discovery or selection. These multicast
messages may not carry a lot of data, but they cause recurring, often
periodic packets to be sent across a domain and waste energy because
of various ill-advised designs, including, but not limited to the
following issues:
(a) The receivers of such packets may not even need to receive them,
but the protocol shares a multicast group with another protocol that
the client does need to receive.
(b) The receiver should not need to receive the packet as far as
multicast is concerned, but the underlying link-layer technology
still makes the receiver consume the packet at link-layer.
(c) The information received is not new, but just periodically
refreshed.
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(d) The packet was originated for a service selection by a client,
and the receiving device is even responding, but the client then
chooses to select another device for the service/resource.
These problems are specifically problematic in the presence of so-
called "sleepy" nodes Section 5.3.2 that need to wake up to receive
such packets (unnecessarily). It is worse, when the network itself
is an LLN network where the forwarders themselves are power
constrained and for example periodic multicasting of such
coordination packets wastes energy on those forwarders as well -
compared to better alternatives.
In 2006, the IETF standardized "Source Specific Multicast" (SSM)
[RFC4607], a variation of IP Multicast that does not allow to perform
these type of coordination functions but is only meant for (and
useable for) actual data distribution. SSM was introduced for other
reasons than the above-described power related issues though, but
deprecating the use of ASM is one way to avoid/minimize its ill-
advised use with these type of coordination functions, when energy
efficiency is an issue. [RFC8815] is an example for deprecating ASM
for other reasons in Service Provider networks.
5.3.1.3. Multicast Problems in Wireless Networks
[RFC9119] covers multicast challenges and solutions (proposals) for
IP Multicast over Wi-Fi. With respect to power consumption, it
discusses the following aspects:
(a) Unnecessary wake-up of power constrained Wi-Fi Stations (STA)
nodes can be minimized by wireless Access Points (APs) that buffer
multicast packets so they are sent only periodically when those nodes
wake up.
(b) WiFi access points with "Multiple Input Multiple Output" (MIMO)
antenna diversity focus sent packets in a way that they are not
"broadcast" to all receivers within a particular maximum distance
from the AP, making WiFi multicast transmission even less desirable.
(c) It lists the most widely deployed protocols using aforementioned
coordination via IP multicast and describes their specific challenges
and possible improvements.
(d) Existing proprietary conversion of WiFi multicast to Wi-Fi
unicast packets.
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[I-D.desmouceaux-ipv6-mcast-wifi-power-usage] focuses on IPv6-related
concerns of multicast traffic in large wireless network. This
document provides as set of statistics and the induced device power
consumption of such flows.
5.3.2. Sleepy Nodes
Sleepy nodes are one of the most common design solutions in support
of power saving. This includes LLN level constrained nodes, but also
nodes with significant battery capacity, such as mobile phones,
tablets and notebooks, because battery lifetime has long since been a
key selling factor. In result, vendors do attempt to optimize power
consumption across all hardware and software components of such
nodes, including the interface hardware and protocols used across the
nodes WiFi and mobile radios.
Restating from [I-D.bormann-core-roadmap-05]: CoAP has basic support
for sleepy nodes by allowing caching of resource information in (non-
sleepy) proxy nodes. [RFC7641] enhances this support by enabling
sleepy nodes to update caching intermediaries on their own schedule.
Around 2012/2013, there was significant review of further review of
further support for sleepy nodes in CoAP, resulting in a long list of
drafts, whose sleepy nodes benefits are discussed in
[I-D.bormann-core-roadmap-05]: [I-D.vial-core-mirror-server],
[I-D.vial-core-mirror-proxy], [I-D.fossati-core-publish-option],
[I-D.giacomin-core-sleepy-option], [I-D.castellani-core-alive],
[I-D.rahman-core-sleepy-problem-statement], [I-D.rahman-core-sleepy],
[I-D.rahman-core-sleepy-nodes-do-we-need],
[I-D.fossati-core-monitor-option]. None of these drafts proceeded
though.
One partial solution to some sleepy node issues related to their
energy consumption, especially the ones caused by the use of
multicast Section 5.3.1.2, Section 5.3.1.3 is the use of the
"Constrained RESTful Environments (CoRE) Resource Directory" (CoRE-
RD) [RFC9176]. It allows for sleepy nodes to register discover and
register resources via unicast and avoids waking up sleepy nodes when
they are not selected by a resouce consumer.
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An partial alternative to CoRE-RD is the "DNS-Based Service
Discovery" {DNS-SD} [RFC6763] combined with for example "Service
Registration Protocol for DNS-Based Service Discovery"
[I-D.ietf-dnssd-srp]. Services can be seen as a subset of resources,
and in networks where DNS has to be supported anyhow for other
reasons, DNS-SD may be a sufficient alternative to CoRE-RD. It is
used for example in Thread https://en.wikipedia.org/wiki/
Thread_(network_protocol) for this purpose and the only multicast
based coordination is the one to establish network wide parameters,
such as the address(es) of DNS-SD server(s).
"Building Power-Efficient Constrained Application Protocol (CoAP)
Devices for Cellular Networks" [RFC9178] discusses sleepy devices,
especially the use of CoAP PubSub [I-D.ietf-core-coap-pubsub] as a
mechanism to build proxies for sleepy devices. "Sensor Measurement
Lists (SenML)", Standardized proxy infrastructures are best built
with standard data models, such as "Sensor Measurement Lists" (SenML)
[RFC8428] for sensors, likely the largest number of sleepy devices,
especially in LLN.
"Reducing Energy Consumption of Router Advertisements", [RFC7772]
eliminates/reduces the energy impact for sleepy nodes of the
ubiquitous IPv6 "Neighbor Discovery" (ND) protocol by giving
recommends for replacing multicast "Router Advertisement" (RA)
messages with so-called directed unicast versions, therefore not
waking up sleepy nodes (with an IP multicast RA message). This was
already allowed in ND [RFC4861], but not recommended as the default.
Note that [RFC7772] does not provide all the energy related
optimizations of ND as developed by 6LoWPAN through [RFC6775].
[I-D.chakrabarti-nordmark-energy-aware-nd] proposes generalizations
for those applications for to all IPv6 links, but was not further
pursued by the IETF so far.
5.4. (Lack of) Power Benchmarking Proposals
[I-D.petrescu-v6ops-ipv6-power-ipv4] presented some measurement
results of the power consumption when using IPv6 vs IPv4 with a focus
on mobile devices. Such measurements are not backed with formal
benchmarking methodologies so that solid and reliable references are
set to compare and interpret data.
https://www.ietf.org/proceedings/103/slides/slides-103-saag-iot-
benchmarking-00 presented a benchmark example but with a focus on
power cost of encryption.
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6. Energy Management Networks
Use of IETF protocol networks in networks that operate power
consumption and production is another broad area of digitization.
6.1. Smart Grid
"Smart Grid" is the most well-known instance of such energy
management networks. According to https://en.wikipedia.org/wiki/
Smart_grid, the term covers aspects mostly centered around
intelligent measured and controlled consumption of energy. This
includes "Advanced Metering Infrastructure" / "Smart Meters", remote
controllable "distribution boards", "circuit breakers", "load
control" and "smart appliances". Use cases for the "Smart Grid"
include for example timed and measured operations of home devices
such as washers or charging cars, when energy consumption is below
average.
The 2011 "Internet Protocols for the Smart Grid" [RFC6272] is a quite
comprehensive (66 page) overview of all IETF protocols considered to
be necessary or beneficial for Smart Grid networks. This document
was written in response to interest by the (not-yet-smart grid)
community in utilizing the IETF TCP/IP technologies to evolve
previously non-TCP/IP network, and the risk that unnecessary
reinvention of the wheel/protocols would be done by that community
instead of reusing what was already well specified by the IETF.
Most of the overview in this document is not specific to networks
used for Smart Grid applications but just summarized in the document
for the above described outreach and education to the community. The
aspects most specific to Smart Grids is the back in 2011 still
somewhat in its infancy adaptation of IPv6 network technologies to
LLN networks (see Section 5.1): smart meters, circuit breakers, load
measurement devices, car chargers and so on - all those devices would
most likely be connected to the network via a low-power radio
networks, which ideally would utilize IPv6 directly. Support for LLN
networks with IPv6 has well improved in IETF specifications in the
past decade.
6.2. Syncro Phasor Networks
Power output of multiple power plants/generators into the same power
grid needs to be synchronized by power levels based on consumption
and power phase (50/60Hz depending on continent) to avoid that energy
created out-of-phase is not only wasted, but would actually burn out
power lines or create permanent damage in power generators. When
generators go out-of-sync, they have to be emergency switched off,
resulting in (rolling-)blackouts, worsening the conditions beyond its
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likely root-cause such as a single overloaded limited region.
Syncro Phasor Networks are networks whose goal it is to support
synchronization of power generators across a power grid, ultimately
also permitting to build larger and more resilient power grids.
"Power Measurement Units" (PMU) are their core sensoring elements.
Since about 2012? these networks have started to move from
traditional SCADA towards more TCP/IP based networking and
application technologies "to improve power system reliability and
visibility through wide area measurement and control, by fostering
the use and capabilities of synchrophasor technology"
(www.naspi.org).
With their fast control loop reaction time and measurement
requirements, they also benefit from reliable, fast propagation of
PMU data as well as stricter clock synchronization than most Smart
Grid applications. For example, transmission lines expand under heat
that s caused by electrical load and/or environmental temperature by
as much as 30% (between coldest and hottest or highest-load times),
impacting the necessary phase relationship of power generation on
either end (speed of light propagation speed based on effective
length of contracted/expanded wire).
The length of transmission wires can be measured from data sent
across the transmission lines and measuring their propagation latency
with the help of accurate clock synchronization between sender and
receiver(s), using for example network-based clock synchronization
protocols. The IETF "Network Time Protocol version 4" (NTPv4),
[RFC5905] is one option for this. The IEEE PTP protocol is often
preferred though because it specifies better how measurements can be
integrated at the hardware level of Ethernet interfaces, thus
allowing easier to achieve higher accuracy, such as Maximum Time
Interval (MTIE) errors of less than 1 msec. See for example
[NASPICLOCK].
The "North American Syncro Phasor Initiative" (NASPI),
https://www.naspi.org is an example organization in support of syncro
phasor networking. It is an ongoing project by the USA "Department
of Energy" (DoE).
7. (Limited) Energy Management for Networks
7.1. Some Metrics
A 2010-2013 draft [I-D.manral-bmwg-power-usage], which was not
adopted discussed and proposed metrics for power consumption that
where intended to be used for benchmarking.
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The later work in Section 7.2 referred instead to other metrics for
measuring power consumption from other SDOs.
A 2011-2012 draft [I-D.jennings-energy-pricing], which was not
adopted, discusses and proposes a data model to communicate time-
varying cost of energy in support of enabling time-shifting of
network attached or managed equipment consumption of power.
7.2. EMAN WG
While the IETF did specify a few MIBs with aspects related to of
power management, it was only with the formation of the "Energy
Management" (EMAN) WG which ran from 2010 to 2015 and released 7 RFC,
that the IETF produced a comprehensive set of MIB based standards for
managing energy/power for network equipment and associated devices
and integrated prior scattered power management related work in the
IETF.
EMAN produced (solely) a set of data/information models (MIBs). It
does not introduce any new protocol/stacks nor does it address
"questions regarding Smart Grid, electricity producers, and
distributors" (from [RFC7603]).
[I-D.claise-power-management-arch] describes the initial EMAN
architecture as envisioned by some of the core contributors to the
WG. It was rewritten in EMAN as the "Energy Management Framework"
[RFC7326]. "Requirements for Energy Management" are defined in
[RFC6988].
According to [RFC7326], "the (EMAN) framework presents a physical
reference model and information model. The information model
consists of an Energy Management Domain as a set of Energy Objects.
Each Energy Object can be attributed with identity, classification,
and context. Energy Objects can be monitored and controlled with
respect to power, Power State, energy, demand, Power Attributes, and
battery. Additionally, the framework models relationships and
capabilities between Energy Objects."
One category of use-cases of particular interest to network equipment
vendors was and is the management of "Power over Ethernet" via the
EMAN framework, measuring and controlling ethernet connected devices
through their PoE supplied power. Besides industrial, surveillance
cameras and office equipment, such as WiFi access points and phones,
PoE is also positioned as a new approach for replacing most in-
building automation components including security control for doors/
windows, as well as environmental controls and lighting through the
use of an in-ceiling, PoE enabled IP/ethernet infrastructure.
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EMAN produced version 4 of the "Entity MIB" (ENTITY-MIB) [RFC6933],
primarily to introduce globally unique UUIDs for physical entities
that allows to better link across different entities, such as a PoE
port on an ethernet switch and the device connected to that switch
port.
The "Monitoring and Control MIB for Power and Energy" [RFC7460]
specifies a MIB for monitoring for Power State and energy consumption
of networked. The document discusses the link with other MIBs such
as the ENTITY-MIB, the ENTITY-SENSOR-MIB [RFC3433] for which it is
amending missing accuracy information to meet IEC power monitoring
requirements, the "Power Ethernet MIB" (POWER-ETHERNET-MIB) [RFC3621]
to manage PoE, and the pre-existing IETF MIB for Uninterruptable
Power Supplies (UPS) (UPS-MIB) [RFC1628], allowing for example to
build control systems that manage shutdowns of devices in case of
power failure based on UPS battery capacity and device consumptions/
priorities. Similarly, the EMAN "Definition of Managed Objects for
Battery Monitoring" [RFC7577] defines objects to support battery
monitoring in managed devices.
The pre-existing IETF "Entity State MIB" (ENTITY-STATE-MIB) [RFC4268]
allows to specify the operational state of entities specified via the
ENTITY-MIB respective to their power consumption and operational
capabilities (e.g.: "coldStandby", "hotStandby", "ready" etc.).
Devices can also act as proxies to provide a MIB interfaces for
monitoring and control of power for other devices, that may use other
protocols, such as in case of a home gateway interfacing with various
vendor specific protocols of home equipment.
The EMAN "Energy Object Context MIB" [RFC7461] defines the ENERGY-
OBJECT-CONTEXT-MIB and IANA-ENERGY-RELATION-MIB, both of which serve
to "address device identification, context information, and the
energy relationships between devices" according to [RFC7461].
To automatically discover and negotiate PoE power consumption between
switch and client, non-IETF technologies, such as IEEE "Link Layer
Discovery Protocol" (LLDP) and proprietary MIBs for it, such as LLDP-
EXT-MED-MIB can be used.
Finally, the "Energy Management (EMAN) Applicability Statement"
[RFC7603] provides an overview of EMAN with a user/operator
perspective, also reviewing a range of typical scenarios it can
support as well as how it could/can link to a variety of pre-
existing, non-IETF standards relevant for power management. Such
intended applicability includes home, core, and DC networks.
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There are currently no YANG equivalent modules. Such modules would
not only be designed to echo the EMAN MIBs but would also allow to
control dedicated power optimization engines instead of relying upon
static and frozen vendor-specific optimization.
8. Power-Awareness in Forwarding and Routing Protocols
8.1. Power Aware Networks (PANET)
In 2013/2014, some drafts proposed how networks themselves,
specifically those of Internet Service Providers (ISP) could
dynamically regulate their power consumption based on the required
performance, for example by switching off or low-powering non-needed
components (links, nodes, linecards) or changing speeds on links, or
reducing clock-rates of processing elements, and/or routing traffic
to utilize as few components as will support the required
performance. The authors called this "Power Aware Networks" (PANET),
even though no awareness of actual power consumption is required in
this approach.
The 2013 "Power-Aware Networks (PANET): Problem Statement"
[I-D.zhang-panet-problem-statement] gives an overview of this
concept, and so does "Power-aware Routing and Traffic Engineering:
Requirements, Approaches, and Issues", [I-D.zhang-greennet] from the
same year.
The 2014 [I-D.retana-rtgwg-eacp] exemplifies the concept and
discusses key challenges such as the reduced resilience against
errors when redundant components are switched off, the risk of
increased stretch (path length) and therefore latency under partial
network component shutdown or downspeeding, as well as the idea of
saving energy through (periodic) microsleeps such as possible with
"Energy Efficient Ethernet" https://en.wikipedia.org/wiki/Energy-
Efficient_Ethernet links. The 2013 draft "Reducing Power Consumption
using BGP with power source data",
[I-D.mjsraman-panet-inter-as-power-source] proposed BGP attributes to
allow calculation of power efficient (or for example green) paths.
One core market driver for this work where rolling blackouts that
especially affected India at the time of these drafts, raising the
desire to be for example reducing the total power consumption of a
network in times of such energy emergencies.
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While there was technical interest in the IETF, the market
significance for the vendors mostly present in the IETF was
considered as not to be important enough. Likewise, traditional
routers, unlike for example todays standard PC hardware designs do
exhibit little power savings upon shutdown of components such as
line-cards or interfaces.
In addition, an SDN / controller-based solution where relatively in
their infancy back in 2013/2014, and technologies that would allow
for SDN controller to have resilient (self-healing) connectivity such
as described in [RFC8368]/[RFC8994] was also not available, making
the risk of severely impacting network reliability one of the key
factors for this PANET work to not proceed so far.
8.2. SDN-based Semantic Forwarding
Recently, [I-D.boucadair-irtf-sdn-and-semantic-routing] provided the
following feature as an examples of capabilities that can be offered
by appropriate control of forwarding elements:
Energy-efficient Forwarding: An important effort was made in the past
to optimize the energy consumption of network elements. However,
such optimization is node-specific and no standard means to optimize
the energy consumption at the scale of the network have been defined.
For example, many nodes (also, service cards) are deployed as
backups.
A controller-based approach can be implemented so that the route
selection process optimizes the overall energy consumption of a path.
Such a process takes into account the current load, avoids waking
nodes/cards for handling "sparse" traffic (i.e., a minor portion of
the total traffic), considers node-specific data (e.g., [RFC7460]),
etc. This off-line Semantic Routing approach will transition
specific cards/nodes to "idle" and wake them as appropriate, etc.,
without breaking service objectives. Moreover, such an approach will
have to maintain an up-to-date topology even if a node is in an
"idle" state (such nodes may be removed from adjacency tables if they
don't participate in routing advertisements).
8.3. Misc
The non-adopted, expired 2013 draft
[I-D.okamoto-ccamp-midori-gmpls-extension-reqs] discusses power
awareness in routing in conjunction with Traffic Engineering
(tunnels), specifically in the context of Generalized MPLS (GMPLS),
e.g.: varous L2 technologies such as switched optical fiber networks.
It primarily claims the issue that the existing management objects
are not sufficient to express energy management related aspects, and
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thus do not allow to build energy conscious policies into PCE for
such GMPLS networks.
The non-adopted 2013 "Requirements for an Energy-Efficient Network
System", [I-D.suzuki-eens-requirements] proposes a signaling of
network capacity towards DC, for example based on load or network
energy management in support of appropriate performance control (such
as VM migration) the DC - or vice versa (DC load-based traffic
engineering in the network to support that DC load).
The non-adopted 2013 "Building power optimal Multicast Trees"
[I-D.mjsraman-rtgwg-pim-power] proposes that (PIM based) IP Multicast
routing could perform local routing choices in the case of "Equal
Cost MultiPath" (ECMP) "Reverse Path Forwarding" (RPF) alternatives
based on the energy that would be consumed in the router, such as
when one ECMP alternative would use a more power efficient linecard
or when one ECMP choice was on the same linecard as the interfaces to
which the packets would need to be routed (and therefore avoiding to
forward the packet across separate ingress and egress linecards).
9. Gaps
The 2013 "Towards an Energy-Efficient Internet"
[I-D.winter-energy-efficient-internet] summarizes some of the same
work items as this document (as written back in 2013) and lists
additional more non-adopted drafts. It also identifies three areas
of gaps, that it suggests the IETF to work on: "Load-adaptive
Resource Management", "Energy-efficient Protocol Design" and "Energy-
efficiency Metrics and Standard Benchmarking Methodologies".
Some aspects for those areas of gaps where partially tackled by later
work in the IETF, but broadly speaking, most of those areas remain
open to a wide range of possible further IETF/IRTF work.
10. Acknowledgments
Thanks for Fred Baker for his review and suggestions.
11. Changelog
[RFC-Editor: this section to be removed in final document.]
The master for this document is hosted at http://github.com/toerless/
energy. Please submit Issues and/or Pull-requests for proposed
changes or join the team of authors and edit yourself.
00: Initial version
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01: Added Co-author (Mohamed Boucadair) - long list of typo fixes,
editorial improvements in abstract, introduction and other chapters.
Added section on satellite networks, devices with batteries, power
benchmarking and SDN-based forwarding semantics.
02: Minor text edits (med), add pointer to additional draft (med),
Added co-author pascal (tte),
03: Aded Jeff Tentsura as co-author
04: Various textual fixups, added new versions of RFC for references
using obsoleted RFCs, so that both original and latest are
referenced.
12. Informative References
[BOUNDED_LATENCY]
Cruz, R.L., "A calculus for network delay. I. Network
elements in isolation", DOI 10.1109/18.61109,
IEEE Transactions on Information Theory ( Volume: 37,
Issue: 1), 1991,
<https://ieeexplore.ieee.org/document/61109>.
[I-D.ajunior-energy-awareness-00]
Junior, A. and R. C. Sofia, "Energy-awareness metrics
global applicability guidelines", Work in Progress,
Internet-Draft, draft-ajunior-energy-awareness-00, 16
October 2012, <https://datatracker.ietf.org/doc/html/
draft-ajunior-energy-awareness-00>.
[I-D.bormann-core-roadmap-05]
Bormann, C., "CoRE Roadmap and Implementation Guide", Work
in Progress, Internet-Draft, draft-bormann-core-roadmap-
05, 21 October 2013,
<https://datatracker.ietf.org/doc/html/draft-bormann-core-
roadmap-05>.
[I-D.boucadair-irtf-sdn-and-semantic-routing]
Boucadair, M., Trossen, D., and A. Farrel, "Considerations
for the use of SDN in Semantic Routing Networks", Work in
Progress, Internet-Draft, draft-boucadair-irtf-sdn-and-
semantic-routing-01, 31 May 2022,
<https://datatracker.ietf.org/doc/html/draft-boucadair-
irtf-sdn-and-semantic-routing-01>.
[I-D.castellani-core-alive]
Castellani, A. P. and S. Loreto, "CoAP Alive Message",
Work in Progress, Internet-Draft, draft-castellani-core-
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alive-00, 29 March 2012,
<https://datatracker.ietf.org/doc/html/draft-castellani-
core-alive-00>.
[I-D.chakrabarti-nordmark-energy-aware-nd]
Chakrabarti, S., Nordmark, E., and M. Cullen, "Energy
Aware IPv6 Neighbor Discovery Optimizations", Work in
Progress, Internet-Draft, draft-chakrabarti-nordmark-
energy-aware-nd-02, 12 March 2012,
<https://datatracker.ietf.org/doc/html/draft-chakrabarti-
nordmark-energy-aware-nd-02>.
[I-D.claise-power-management-arch]
Claise, B., Parello, J., and B. Schoening, "Power
Management Architecture", Work in Progress, Internet-
Draft, draft-claise-power-management-arch-02, 22 October
2010, <https://datatracker.ietf.org/doc/html/draft-claise-
power-management-arch-02>.
[I-D.desmouceaux-ipv6-mcast-wifi-power-usage]
Desmouceaux, Y., "Power consumption due to IPv6 multicast
on WiFi devices", Work in Progress, Internet-Draft, draft-
desmouceaux-ipv6-mcast-wifi-power-usage-01, 1 August 2014,
<https://datatracker.ietf.org/doc/html/draft-desmouceaux-
ipv6-mcast-wifi-power-usage-01>.
[I-D.fossati-core-monitor-option]
Fossati, T., Giacomin, P., and S. Loreto, "Monitor Option
for CoAP", Work in Progress, Internet-Draft, draft-
fossati-core-monitor-option-00, 9 July 2012,
<https://datatracker.ietf.org/doc/html/draft-fossati-core-
monitor-option-00>.
[I-D.fossati-core-publish-option]
Fossati, T., Giacomin, P., and S. Loreto, "Publish Option
for CoAP", Work in Progress, Internet-Draft, draft-
fossati-core-publish-option-03, 6 January 2014,
<https://datatracker.ietf.org/doc/html/draft-fossati-core-
publish-option-03>.
[I-D.giacomin-core-sleepy-option]
Fossati, T., Giacomin, P., Loreto, S., and M. Rossini,
"Sleepy Option for CoAP", Work in Progress, Internet-
Draft, draft-giacomin-core-sleepy-option-00, 29 February
2012, <https://datatracker.ietf.org/doc/html/draft-
giacomin-core-sleepy-option-00>.
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[I-D.ietf-core-coap-pubsub]
Koster, M., Keränen, A., and J. Jimenez, "Publish-
Subscribe Broker for the Constrained Application Protocol
(CoAP)", Work in Progress, Internet-Draft, draft-ietf-
core-coap-pubsub-11, 7 November 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-core-
coap-pubsub-11>.
[I-D.ietf-dnssd-srp]
Lemon, T. and S. Cheshire, "Service Registration Protocol
for DNS-Based Service Discovery", Work in Progress,
Internet-Draft, draft-ietf-dnssd-srp-18, 9 January 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-dnssd-
srp-18>.
[I-D.ietf-tcpm-rfc793bis]
Eddy, W., "Transmission Control Protocol (TCP)", Work in
Progress, Internet-Draft, draft-ietf-tcpm-rfc793bis-28, 7
March 2022, <https://datatracker.ietf.org/doc/html/draft-
ietf-tcpm-rfc793bis-28>.
[I-D.jennings-energy-pricing]
Jennings, C. F. and B. Nordman, "Communication of Energy
Price Information", Work in Progress, Internet-Draft,
draft-jennings-energy-pricing-01, 10 July 2011,
<https://datatracker.ietf.org/doc/html/draft-jennings-
energy-pricing-01>.
[I-D.lhan-problems-requirements-satellite-net]
Han, L., Li, R., Retana, A., chenmeiling, Su, L., Jiang,
T., and N. Wang, "Problems and Requirements of Satellite
Constellation for Internet", Work in Progress, Internet-
Draft, draft-lhan-problems-requirements-satellite-net-04,
4 January 2023, <https://datatracker.ietf.org/doc/html/
draft-lhan-problems-requirements-satellite-net-04>.
[I-D.manral-bmwg-power-usage]
Manral, V., Sharma, P., Banerjee, S., and Y. Ping,
"Benchmarking Power usage of networking devices", Work in
Progress, Internet-Draft, draft-manral-bmwg-power-usage-
04, 12 March 2013, <https://datatracker.ietf.org/doc/html/
draft-manral-bmwg-power-usage-04>.
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[I-D.mjsraman-panet-inter-as-power-source]
Raman, S., Venkataswami, B. V., Raina, G., and K.
Veezhinathan, "Reducing Power Consumption using BGP with
power source data", Work in Progress, Internet-Draft,
draft-mjsraman-panet-inter-as-power-source-00, 25 January
2013, <https://datatracker.ietf.org/doc/html/draft-
mjsraman-panet-inter-as-power-source-00>.
[I-D.mjsraman-rtgwg-pim-power]
Raman, S., Venkataswami, B. V., Raina, G., and V. Srini,
"Building power optimal Multicast Trees", Work in
Progress, Internet-Draft, draft-mjsraman-rtgwg-pim-power-
02, 27 March 2012, <https://datatracker.ietf.org/doc/html/
draft-mjsraman-rtgwg-pim-power-02>.
[I-D.okamoto-ccamp-midori-gmpls-extension-reqs]
Okamoto, S., "Requirements of GMPLS Extensions for Energy
Efficient Traffic Engineering", Work in Progress,
Internet-Draft, draft-okamoto-ccamp-midori-gmpls-
extension-reqs-02, 14 March 2013,
<https://datatracker.ietf.org/doc/html/draft-okamoto-
ccamp-midori-gmpls-extension-reqs-02>.
[I-D.petrescu-v6ops-ipv6-power-ipv4]
Petrescu, A., Saïd, S. B. H., Philippot, O., and T.
Vincent, "Power Consumption of IPv6 vs IPv4 in
Smartphone", Work in Progress, Internet-Draft, draft-
petrescu-v6ops-ipv6-power-ipv4-00, 13 March 2017,
<https://datatracker.ietf.org/doc/html/draft-petrescu-
v6ops-ipv6-power-ipv4-00>.
[I-D.rahman-core-sleepy]
Rahman, A., "Enhanced Sleepy Node Support for CoAP", Work
in Progress, Internet-Draft, draft-rahman-core-sleepy-05,
11 February 2014, <https://datatracker.ietf.org/doc/html/
draft-rahman-core-sleepy-05>.
[I-D.rahman-core-sleepy-nodes-do-we-need]
Rahman, A., "Sleepy Devices: Do we need to Support them in
CORE?", Work in Progress, Internet-Draft, draft-rahman-
core-sleepy-nodes-do-we-need-01, 11 February 2014,
<https://datatracker.ietf.org/doc/html/draft-rahman-core-
sleepy-nodes-do-we-need-01>.
[I-D.rahman-core-sleepy-problem-statement]
Rahman, A., Fossati, T., Loreto, S., and M. Vial, "Sleepy
Devices in CoAP - Problem Statement", Work in Progress,
Internet-Draft, draft-rahman-core-sleepy-problem-
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statement-01, 21 October 2012,
<https://datatracker.ietf.org/doc/html/draft-rahman-core-
sleepy-problem-statement-01>.
[I-D.retana-rtgwg-eacp]
Retana, A., White, R., and M. Paul, "A Framework for
Energy Aware Control Planes", Work in Progress, Internet-
Draft, draft-retana-rtgwg-eacp-06, 22 February 2023,
<https://datatracker.ietf.org/doc/html/draft-retana-rtgwg-
eacp-06>.
[I-D.suzuki-eens-requirements]
Suzuki, T. and T. Tarui, "Requirements for an Energy-
Efficient Network System", Work in Progress, Internet-
Draft, draft-suzuki-eens-requirements-00, 15 October 2012,
<https://datatracker.ietf.org/doc/html/draft-suzuki-eens-
requirements-00>.
[I-D.vial-core-mirror-proxy]
Vial, M., "CoRE Mirror Server", Work in Progress,
Internet-Draft, draft-vial-core-mirror-proxy-01, 13 July
2012, <https://datatracker.ietf.org/doc/html/draft-vial-
core-mirror-proxy-01>.
[I-D.vial-core-mirror-server]
Vial, M., "CoRE Mirror Server", Work in Progress,
Internet-Draft, draft-vial-core-mirror-server-01, 10 April
2013, <https://datatracker.ietf.org/doc/html/draft-vial-
core-mirror-server-01>.
[I-D.wang-roll-energy-optimization-scheme]
Wang, H., Wei, M., Li, S., Huang, Q., Wang, P., and C.
Wang, "An energy optimization routing scheme for LLSs",
Work in Progress, Internet-Draft, draft-wang-roll-energy-
optimization-scheme-00, 21 February 2017,
<https://datatracker.ietf.org/doc/html/draft-wang-roll-
energy-optimization-scheme-00>.
[I-D.winter-energy-efficient-internet]
Winter, R., Jeong, S., and J. Choi, "Towards an Energy-
Efficient Internet", Work in Progress, Internet-Draft,
draft-winter-energy-efficient-internet-01, 22 October
2012, <https://datatracker.ietf.org/doc/html/draft-winter-
energy-efficient-internet-01>.
[I-D.zhang-greennet]
Zhang, B., Shi, J., Dong, J., and M. Zhang, "Power-aware
Routing and Traffic Engineering: Requirements, Approaches,
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and Issues", Work in Progress, Internet-Draft, draft-
zhang-greennet-01, 10 January 2013,
<https://datatracker.ietf.org/doc/html/draft-zhang-
greennet-01>.
[I-D.zhang-panet-problem-statement]
Zhang, B., Shi, J., Dong, J., Zhang, M., and M. Boucadair,
"Power-Aware Networks (PANET): Problem Statement", Work in
Progress, Internet-Draft, draft-zhang-panet-problem-
statement-03, 15 October 2013,
<https://datatracker.ietf.org/doc/html/draft-zhang-panet-
problem-statement-03>.
[ISO10589-Second-Edition]
Standardization,, I. O. for., "Intermediate system to
Intermediate system intra-domain routeing information
exchange protocol for use in conjunction with the protocol
for providing the connectionless-mode Network Service (ISO
8473)", ISO ISO/IEC 10589:2002, Second Edition, Nov.
2002., n.d..
[NASPICLOCK]
Force, N. T. S. T., "Time Synchronization in the Electric
Power System", March 2017,
<https://www.naspi.org/sites/default/files/
reference_documents/tstf_electric_power_system_report_pnnl
_26331_march_2017_0.pdf>.
[RFC1112] Deering, S., "Host extensions for IP multicasting", STD 5,
RFC 1112, DOI 10.17487/RFC1112, August 1989,
<https://www.rfc-editor.org/info/rfc1112>.
[RFC1142] Oran, D., Ed., "OSI IS-IS Intra-domain Routing Protocol",
RFC 1142, DOI 10.17487/RFC1142, February 1990,
<https://www.rfc-editor.org/info/rfc1142>.
[RFC1628] Case, J., Ed., "UPS Management Information Base",
RFC 1628, DOI 10.17487/RFC1628, May 1994,
<https://www.rfc-editor.org/info/rfc1628>.
[RFC1866] Berners-Lee, T. and D. Connolly, "Hypertext Markup
Language - 2.0", RFC 1866, DOI 10.17487/RFC1866, November
1995, <https://www.rfc-editor.org/info/rfc1866>.
[RFC1883] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 1883, DOI 10.17487/RFC1883,
December 1995, <https://www.rfc-editor.org/info/rfc1883>.
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[RFC2086] Myers, J., "IMAP4 ACL extension", RFC 2086,
DOI 10.17487/RFC2086, January 1997,
<https://www.rfc-editor.org/info/rfc2086>.
[RFC2212] Shenker, S., Partridge, C., and R. Guerin, "Specification
of Guaranteed Quality of Service", RFC 2212,
DOI 10.17487/RFC2212, September 1997,
<https://www.rfc-editor.org/info/rfc2212>.
[RFC2246] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0",
RFC 2246, DOI 10.17487/RFC2246, January 1999,
<https://www.rfc-editor.org/info/rfc2246>.
[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328,
DOI 10.17487/RFC2328, April 1998,
<https://www.rfc-editor.org/info/rfc2328>.
[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460,
December 1998, <https://www.rfc-editor.org/info/rfc2460>.
[RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z.,
and W. Weiss, "An Architecture for Differentiated
Services", RFC 2475, DOI 10.17487/RFC2475, December 1998,
<https://www.rfc-editor.org/info/rfc2475>.
[RFC2543] Handley, M., Schulzrinne, H., Schooler, E., and J.
Rosenberg, "SIP: Session Initiation Protocol", RFC 2543,
DOI 10.17487/RFC2543, March 1999,
<https://www.rfc-editor.org/info/rfc2543>.
[RFC2822] Resnick, P., Ed., "Internet Message Format", RFC 2822,
DOI 10.17487/RFC2822, April 2001,
<https://www.rfc-editor.org/info/rfc2822>.
[RFC2854] Connolly, D. and L. Masinter, "The 'text/html' Media
Type", RFC 2854, DOI 10.17487/RFC2854, June 2000,
<https://www.rfc-editor.org/info/rfc2854>.
[RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
A., Peterson, J., Sparks, R., Handley, M., and E.
Schooler, "SIP: Session Initiation Protocol", RFC 3261,
DOI 10.17487/RFC3261, June 2002,
<https://www.rfc-editor.org/info/rfc3261>.
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[RFC3433] Bierman, A., Romascanu, D., and K.C. Norseth, "Entity
Sensor Management Information Base", RFC 3433,
DOI 10.17487/RFC3433, December 2002,
<https://www.rfc-editor.org/info/rfc3433>.
[RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V.
Jacobson, "RTP: A Transport Protocol for Real-Time
Applications", STD 64, RFC 3550, DOI 10.17487/RFC3550,
July 2003, <https://www.rfc-editor.org/info/rfc3550>.
[RFC3621] Berger, A. and D. Romascanu, "Power Ethernet MIB",
RFC 3621, DOI 10.17487/RFC3621, December 2003,
<https://www.rfc-editor.org/info/rfc3621>.
[RFC3948] Huttunen, A., Swander, B., Volpe, V., DiBurro, L., and M.
Stenberg, "UDP Encapsulation of IPsec ESP Packets",
RFC 3948, DOI 10.17487/RFC3948, January 2005,
<https://www.rfc-editor.org/info/rfc3948>.
[RFC3977] Feather, C., "Network News Transfer Protocol (NNTP)",
RFC 3977, DOI 10.17487/RFC3977, October 2006,
<https://www.rfc-editor.org/info/rfc3977>.
[RFC4268] Chisholm, S. and D. Perkins, "Entity State MIB", RFC 4268,
DOI 10.17487/RFC4268, November 2005,
<https://www.rfc-editor.org/info/rfc4268>.
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
Border Gateway Protocol 4 (BGP-4)", RFC 4271,
DOI 10.17487/RFC4271, January 2006,
<https://www.rfc-editor.org/info/rfc4271>.
[RFC4346] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.1", RFC 4346,
DOI 10.17487/RFC4346, April 2006,
<https://www.rfc-editor.org/info/rfc4346>.
[RFC4607] Holbrook, H. and B. Cain, "Source-Specific Multicast for
IP", RFC 4607, DOI 10.17487/RFC4607, August 2006,
<https://www.rfc-editor.org/info/rfc4607>.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
DOI 10.17487/RFC4861, September 2007,
<https://www.rfc-editor.org/info/rfc4861>.
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[RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler,
"Transmission of IPv6 Packets over IEEE 802.15.4
Networks", RFC 4944, DOI 10.17487/RFC4944, September 2007,
<https://www.rfc-editor.org/info/rfc4944>.
[RFC4949] Shirey, R., "Internet Security Glossary, Version 2",
FYI 36, RFC 4949, DOI 10.17487/RFC4949, August 2007,
<https://www.rfc-editor.org/info/rfc4949>.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246,
DOI 10.17487/RFC5246, August 2008,
<https://www.rfc-editor.org/info/rfc5246>.
[RFC5322] Resnick, P., Ed., "Internet Message Format", RFC 5322,
DOI 10.17487/RFC5322, October 2008,
<https://www.rfc-editor.org/info/rfc5322>.
[RFC5548] Dohler, M., Ed., Watteyne, T., Ed., Winter, T., Ed., and
D. Barthel, Ed., "Routing Requirements for Urban Low-Power
and Lossy Networks", RFC 5548, DOI 10.17487/RFC5548, May
2009, <https://www.rfc-editor.org/info/rfc5548>.
[RFC5673] Pister, K., Ed., Thubert, P., Ed., Dwars, S., and T.
Phinney, "Industrial Routing Requirements in Low-Power and
Lossy Networks", RFC 5673, DOI 10.17487/RFC5673, October
2009, <https://www.rfc-editor.org/info/rfc5673>.
[RFC5826] Brandt, A., Buron, J., and G. Porcu, "Home Automation
Routing Requirements in Low-Power and Lossy Networks",
RFC 5826, DOI 10.17487/RFC5826, April 2010,
<https://www.rfc-editor.org/info/rfc5826>.
[RFC5867] Martocci, J., Ed., De Mil, P., Riou, N., and W. Vermeylen,
"Building Automation Routing Requirements in Low-Power and
Lossy Networks", RFC 5867, DOI 10.17487/RFC5867, June
2010, <https://www.rfc-editor.org/info/rfc5867>.
[RFC5905] Mills, D., Martin, J., Ed., Burbank, J., and W. Kasch,
"Network Time Protocol Version 4: Protocol and Algorithms
Specification", RFC 5905, DOI 10.17487/RFC5905, June 2010,
<https://www.rfc-editor.org/info/rfc5905>.
[RFC6206] Levis, P., Clausen, T., Hui, J., Gnawali, O., and J. Ko,
"The Trickle Algorithm", RFC 6206, DOI 10.17487/RFC6206,
March 2011, <https://www.rfc-editor.org/info/rfc6206>.
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[RFC6272] Baker, F. and D. Meyer, "Internet Protocols for the Smart
Grid", RFC 6272, DOI 10.17487/RFC6272, June 2011,
<https://www.rfc-editor.org/info/rfc6272>.
[RFC6282] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6
Datagrams over IEEE 802.15.4-Based Networks", RFC 6282,
DOI 10.17487/RFC6282, September 2011,
<https://www.rfc-editor.org/info/rfc6282>.
[RFC6550] Winter, T., Ed., Thubert, P., Ed., Brandt, A., Hui, J.,
Kelsey, R., Levis, P., Pister, K., Struik, R., Vasseur,
JP., and R. Alexander, "RPL: IPv6 Routing Protocol for
Low-Power and Lossy Networks", RFC 6550,
DOI 10.17487/RFC6550, March 2012,
<https://www.rfc-editor.org/info/rfc6550>.
[RFC6690] Shelby, Z., "Constrained RESTful Environments (CoRE) Link
Format", RFC 6690, DOI 10.17487/RFC6690, August 2012,
<https://www.rfc-editor.org/info/rfc6690>.
[RFC6763] Cheshire, S. and M. Krochmal, "DNS-Based Service
Discovery", RFC 6763, DOI 10.17487/RFC6763, February 2013,
<https://www.rfc-editor.org/info/rfc6763>.
[RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C.
Bormann, "Neighbor Discovery Optimization for IPv6 over
Low-Power Wireless Personal Area Networks (6LoWPANs)",
RFC 6775, DOI 10.17487/RFC6775, November 2012,
<https://www.rfc-editor.org/info/rfc6775>.
[RFC6887] Wing, D., Ed., Cheshire, S., Boucadair, M., Penno, R., and
P. Selkirk, "Port Control Protocol (PCP)", RFC 6887,
DOI 10.17487/RFC6887, April 2013,
<https://www.rfc-editor.org/info/rfc6887>.
[RFC6933] Bierman, A., Romascanu, D., Quittek, J., and M.
Chandramouli, "Entity MIB (Version 4)", RFC 6933,
DOI 10.17487/RFC6933, May 2013,
<https://www.rfc-editor.org/info/rfc6933>.
[RFC6988] Quittek, J., Ed., Chandramouli, M., Winter, R., Dietz, T.,
and B. Claise, "Requirements for Energy Management",
RFC 6988, DOI 10.17487/RFC6988, September 2013,
<https://www.rfc-editor.org/info/rfc6988>.
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[RFC7030] Pritikin, M., Ed., Yee, P., Ed., and D. Harkins, Ed.,
"Enrollment over Secure Transport", RFC 7030,
DOI 10.17487/RFC7030, October 2013,
<https://www.rfc-editor.org/info/rfc7030>.
[RFC7102] Vasseur, JP., "Terms Used in Routing for Low-Power and
Lossy Networks", RFC 7102, DOI 10.17487/RFC7102, January
2014, <https://www.rfc-editor.org/info/rfc7102>.
[RFC7326] Parello, J., Claise, B., Schoening, B., and J. Quittek,
"Energy Management Framework", RFC 7326,
DOI 10.17487/RFC7326, September 2014,
<https://www.rfc-editor.org/info/rfc7326>.
[RFC7460] Chandramouli, M., Claise, B., Schoening, B., Quittek, J.,
and T. Dietz, "Monitoring and Control MIB for Power and
Energy", RFC 7460, DOI 10.17487/RFC7460, March 2015,
<https://www.rfc-editor.org/info/rfc7460>.
[RFC7461] Parello, J., Claise, B., and M. Chandramouli, "Energy
Object Context MIB", RFC 7461, DOI 10.17487/RFC7461, March
2015, <https://www.rfc-editor.org/info/rfc7461>.
[RFC7577] Quittek, J., Winter, R., and T. Dietz, "Definition of
Managed Objects for Battery Monitoring", RFC 7577,
DOI 10.17487/RFC7577, July 2015,
<https://www.rfc-editor.org/info/rfc7577>.
[RFC7603] Schoening, B., Chandramouli, M., and B. Nordman, "Energy
Management (EMAN) Applicability Statement", RFC 7603,
DOI 10.17487/RFC7603, August 2015,
<https://www.rfc-editor.org/info/rfc7603>.
[RFC7641] Hartke, K., "Observing Resources in the Constrained
Application Protocol (CoAP)", RFC 7641,
DOI 10.17487/RFC7641, September 2015,
<https://www.rfc-editor.org/info/rfc7641>.
[RFC768] Postel, J., "User Datagram Protocol", STD 6, RFC 768,
DOI 10.17487/RFC0768, August 1980,
<https://www.rfc-editor.org/info/rfc768>.
[RFC7733] Brandt, A., Baccelli, E., Cragie, R., and P. van der Stok,
"Applicability Statement: The Use of the Routing Protocol
for Low-Power and Lossy Networks (RPL) Protocol Suite in
Home Automation and Building Control", RFC 7733,
DOI 10.17487/RFC7733, February 2016,
<https://www.rfc-editor.org/info/rfc7733>.
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[RFC7772] Yourtchenko, A. and L. Colitti, "Reducing Energy
Consumption of Router Advertisements", BCP 202, RFC 7772,
DOI 10.17487/RFC7772, February 2016,
<https://www.rfc-editor.org/info/rfc7772>.
[RFC7849] Binet, D., Boucadair, M., Vizdal, A., Chen, G., Heatley,
N., Chandler, R., Michaud, D., Lopez, D., and W. Haeffner,
"An IPv6 Profile for 3GPP Mobile Devices", RFC 7849,
DOI 10.17487/RFC7849, May 2016,
<https://www.rfc-editor.org/info/rfc7849>.
[RFC791] Postel, J., "Internet Protocol", STD 5, RFC 791,
DOI 10.17487/RFC0791, September 1981,
<https://www.rfc-editor.org/info/rfc791>.
[RFC793] Postel, J., "Transmission Control Protocol", RFC 793,
DOI 10.17487/RFC0793, September 1981,
<https://www.rfc-editor.org/info/rfc793>.
[RFC8036] Cam-Winget, N., Ed., Hui, J., and D. Popa, "Applicability
Statement for the Routing Protocol for Low-Power and Lossy
Networks (RPL) in Advanced Metering Infrastructure (AMI)
Networks", RFC 8036, DOI 10.17487/RFC8036, January 2017,
<https://www.rfc-editor.org/info/rfc8036>.
[RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", STD 86, RFC 8200,
DOI 10.17487/RFC8200, July 2017,
<https://www.rfc-editor.org/info/rfc8200>.
[RFC822] Crocker, D., "STANDARD FOR THE FORMAT OF ARPA INTERNET
TEXT MESSAGES", STD 11, RFC 822, DOI 10.17487/RFC0822,
August 1982, <https://www.rfc-editor.org/info/rfc822>.
[RFC8352] Gomez, C., Kovatsch, M., Tian, H., and Z. Cao, Ed.,
"Energy-Efficient Features of Internet of Things
Protocols", RFC 8352, DOI 10.17487/RFC8352, April 2018,
<https://www.rfc-editor.org/info/rfc8352>.
[RFC8368] Eckert, T., Ed. and M. Behringer, "Using an Autonomic
Control Plane for Stable Connectivity of Network
Operations, Administration, and Maintenance (OAM)",
RFC 8368, DOI 10.17487/RFC8368, May 2018,
<https://www.rfc-editor.org/info/rfc8368>.
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[RFC8428] Jennings, C., Shelby, Z., Arkko, J., Keranen, A., and C.
Bormann, "Sensor Measurement Lists (SenML)", RFC 8428,
DOI 10.17487/RFC8428, August 2018,
<https://www.rfc-editor.org/info/rfc8428>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>.
[RFC8575] Jiang, Y., Ed., Liu, X., Xu, J., and R. Cummings, Ed.,
"YANG Data Model for the Precision Time Protocol (PTP)",
RFC 8575, DOI 10.17487/RFC8575, May 2019,
<https://www.rfc-editor.org/info/rfc8575>.
[RFC8613] Selander, G., Mattsson, J., Palombini, F., and L. Seitz,
"Object Security for Constrained RESTful Environments
(OSCORE)", RFC 8613, DOI 10.17487/RFC8613, July 2019,
<https://www.rfc-editor.org/info/rfc8613>.
[RFC8724] Minaburo, A., Toutain, L., Gomez, C., Barthel, D., and JC.
Zuniga, "SCHC: Generic Framework for Static Context Header
Compression and Fragmentation", RFC 8724,
DOI 10.17487/RFC8724, April 2020,
<https://www.rfc-editor.org/info/rfc8724>.
[RFC8815] Abrahamsson, M., Chown, T., Giuliano, L., and T. Eckert,
"Deprecating Any-Source Multicast (ASM) for Interdomain
Multicast", BCP 229, RFC 8815, DOI 10.17487/RFC8815,
August 2020, <https://www.rfc-editor.org/info/rfc8815>.
[RFC8824] Minaburo, A., Toutain, L., and R. Andreasen, "Static
Context Header Compression (SCHC) for the Constrained
Application Protocol (CoAP)", RFC 8824,
DOI 10.17487/RFC8824, June 2021,
<https://www.rfc-editor.org/info/rfc8824>.
[RFC8994] Eckert, T., Ed., Behringer, M., Ed., and S. Bjarnason, "An
Autonomic Control Plane (ACP)", RFC 8994,
DOI 10.17487/RFC8994, May 2021,
<https://www.rfc-editor.org/info/rfc8994>.
[RFC9008] Robles, M.I., Richardson, M., and P. Thubert, "Using RPI
Option Type, Routing Header for Source Routes, and IPv6-
in-IPv6 Encapsulation in the RPL Data Plane", RFC 9008,
DOI 10.17487/RFC9008, April 2021,
<https://www.rfc-editor.org/info/rfc9008>.
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[RFC9010] Thubert, P., Ed. and M. Richardson, "Routing for RPL
(Routing Protocol for Low-Power and Lossy Networks)
Leaves", RFC 9010, DOI 10.17487/RFC9010, April 2021,
<https://www.rfc-editor.org/info/rfc9010>.
[RFC9011] Gimenez, O., Ed. and I. Petrov, Ed., "Static Context
Header Compression and Fragmentation (SCHC) over LoRaWAN",
RFC 9011, DOI 10.17487/RFC9011, April 2021,
<https://www.rfc-editor.org/info/rfc9011>.
[RFC9119] Perkins, C., McBride, M., Stanley, D., Kumari, W., and JC.
Zúñiga, "Multicast Considerations over IEEE 802 Wireless
Media", RFC 9119, DOI 10.17487/RFC9119, October 2021,
<https://www.rfc-editor.org/info/rfc9119>.
[RFC9148] van der Stok, P., Kampanakis, P., Richardson, M., and S.
Raza, "EST-coaps: Enrollment over Secure Transport with
the Secure Constrained Application Protocol", RFC 9148,
DOI 10.17487/RFC9148, April 2022,
<https://www.rfc-editor.org/info/rfc9148>.
[RFC9176] Amsüss, C., Ed., Shelby, Z., Koster, M., Bormann, C., and
P. van der Stok, "Constrained RESTful Environments (CoRE)
Resource Directory", RFC 9176, DOI 10.17487/RFC9176, April
2022, <https://www.rfc-editor.org/info/rfc9176>.
[RFC9178] Arkko, J., Eriksson, A., and A. Keränen, "Building Power-
Efficient Constrained Application Protocol (CoAP) Devices
for Cellular Networks", RFC 9178, DOI 10.17487/RFC9178,
May 2022, <https://www.rfc-editor.org/info/rfc9178>.
[VC2014] Ong, D., Moors, T., and V. Sivaraman, "Comparison of the
energy, carbon and time costs of videoconferencing and in-
person meetings", DOI 10.1016/j.comcom.2014.02.009, 2014,
<https://www.sciencedirect.com/science/article/pii/
S0140366414000620>.
Authors' Addresses
Toerless Eckert (editor)
Futurewei Technologies USA
2220 Central Expressway
Santa Clara, CA 95050
United States of America
Email: tte@cs.fau.de
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Mohamed Boucadair (editor)
Orange
35000 Rennes
France
Email: mohamed.boucadair@orange.com
Pascal Thubert
Cisco Systems, Inc.
45 Allee des Ormes - BP1200, Building D
06254 MOUGINS Sophia Antipolis
France
Phone: +33 497 23 26 34
Email: pthubert@cisco.com
Jeff Tentsura
NVIDIA
United States of America
Email: jefftant.ietf@gmail.com
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