Re: [E-impact] kWh/GB should be banned and the IETF should warn against its use

[Rudolf van der Berg <[e-mail]>]

Dear Marie-Paule,

I find your response a bit surprising. The firm you work for; Orange
doesn't publish statistics on energy intensity in kWh/GB at all. If it
really is as relevant as you say, then I wonder why not.

Furthermore, the GSMA Intelligence unit warns against using these metrics
to compare operators. In  Going green: benchmarking the energy efficiency
of mobile networks (second edition) February 2023, they state that for the
10 operators that participate and the 58 networks reviewed there is a
significant difference in energy intensity as measured in kWh/GB. So much
so that they state:  "Of the participating operators, 66% performed in the
0.1–0.6 kWh/GB range (see Figure 4), meaning that most of the included
networks used 0.1–0.6 kWh to transfer 1 GB of data. Values outside of this
range can be explained by inefficient networks, consumer habits or low data
traffic per connection". Figure 4 then shows a range of values where the
highest value is 20x that of the lowest. This would make me very hesitant
of using such a metric.

In the Netherlands the reported energy use of the mobile networks of
Vodafone and T-Mobile are 110GWh and 130GWh respectively. T-Mobile however
handles twice as much bytes per month as Vodafone. By this metric T-Mobile
is twice as efficient as Vodafone. Which is odd, because they have roughly
the same number of sites and cover the same country. VodafoneZiggo the
cable firm then reports only its IP-traffic and says it uses 13kWh/TB, but
doesn't appear to mention its DVB-C traffic. If kWh/GB had any meaning,
then I would see some correlation between energy use and data use
particularly when data use is twice as much. For some reason that doesn't
appear to happen. KPN in the Netherlands reports on kWh/Gbit/s which means
it doesn't care about traffic as much as capacity. It has also reduced its
energy consumption by 40% in the last decade while traffic grew at a merry
pace. Deutsche Telekom reports that it uses 60kWh per Terabyte, whereas
VodafoneZiggo uses 13 kWh/TB for its fixed network and less than 30kWh/TB
if we take fixed and mobile together. So I don't see how I can inform
policy makers or executives on anything using these numbers. Should I tell
people to use T-Mobile's network in the Netherlands, because it's the most
efficient on mobile? Should I say Deutsche Telekom doesn't know how to run
an efficient network? The numbers are meaningless.

In addition I don't see how it provides any insight into the ecological
footprint of a service. It doesn't matter whether this is provided by a
telco or an OTT service. The network has to run regardless of whether
consumers use the service. The service provider has no influence over the
technical choices of the telecom providers nor how they purchase their
electricity. Given that many European telcos are already purchasing 100%
green energy, we might then as well conclude that the CO2 output should be
nil. Or differently, how would you allocate the energy use of Orange's
service offer in France over the various services of Internet, TV, and
telephony on its fixed network and how to differentiate between fiber and
copper. How would an OTT service provider have to factor in that incumbent
telcos such as Telefonica, TIM, DT and Orange refuse to allow CDNs placed
deeply in their network, unlike BT and KPN, which increases the costs en
environmental impact of carrying traffic.

What I think this quite clearly shows is that kWh/GB is meaningless and has
no relationship to the energy consumption of a network  or service and
doesn't provide any guidance on how to save energy. If anything it promotes
traffic growth, because that makes the metric decrease while all else stays
equal.

So no, it doesn't any of the things you say it does.

Sincerely,

Rudolf

Op do 11 mei 2023 om 13:04 schreef Marie-Paule Odini <[e-mail]>:

> Hello Rudolf,
>
> thank you for your insights on this topic!
>
> I believe that even though the metric does not reflect exactly what the
> actual network elements that carry this traffic consume, the kwh/GB is a
> good indication of the carbon footprint of a given service and shows the
> actual responsability of the service provider that delivers that service.
> Actually from a global perspective the cumulated consumption of the network
> elements, cooling systems, lighting, waste, recycling  etc should be
> considered at some point to actually measure the overall impact of a given
> service.
>
> br, MP
>
> *envoyé :* 11 mai 2023 à 12:24
> *de :* Rudolf van der Berg <[e-mail]>
> *à :* [e-mail]
> *objet :* [E-impact] kWh/GB should be banned and the IETF should warn
> against its use
>
> Dom Robinson looped me in and I now joined the mailing list.
>
> I was surprised to see that kWh/GB and equivalents as measures of
> electricity use of networks and sometimes wider; datacenters and consumer
> electronics, are seriously mentioned by some people on this list. kWh/GB is
> one of the most misleading and scientifically incorrect ways of describing
> the energy use of networks. Even a cursory glance of the academic
> literature shows that estimates range so far and wide that there must be
> something wrong with it. A slightly deeper analysis would show there is no
> basis in physics, electrical engineering, optical and wireless networking,
> protocol design or computer science for relating electricity to an
> arbitrary selection of  groupings of 8 billion bits, modulated, transmitted
> and received over a signal, while generally omitting large numbers of other
> modulations of bits on the same signal.
>
> Now I have only a degree in Public Administration, so I may not know
> perfectly where and how energy use in networks is affected, but I do deal
> with the fall out when others get it wrong, because it stimulates bad ideas
> for regulation that would break the internet instead of save energy. So
> this is a plea for some good data and metrics.
>
> There are several problems with the metric:
>
> 1. Physics: The energy consumption of networking equipment is to a large
> extent based on how far the signal needs to travel, spectral bandwidth and
> the medium that it is transmitted over. When transmitted through copper
> generally more energy is needed to achieve a distance and the signal fades
> quicker than over fibre. In wireless networks the frequency and coverage
> area affect energy use. Modulations can affect energy use, but to a much
> lesser extent than distance, area, spetral use, medium etc.
> 2. Electrical/optical engineering: Emitting a signal through the use of
> electro/optical waves is one thing, the detection of signals appears to be
> a greater problem. This was known in the first telegraph systems and
> demonstrated when increasing power blew up the first transatlantic
> telegraph. In order to limit noise and all kinds of artifacts and to best
> detect signals a lower power bearer is preferred. Less power, less noise,
> more signal, the exact opposie of kWh/GB
> 3. networking: the essence of networking is to communicate. In order to be
> able to communicate, devices need to be active to receive. Receiving
> requires energy even when no human or machine interpretable data is
> received. At the same time for many types of networking there is a need
> either to have occasional signals exchanged to validate the state of the
> network, to update locations of mobile equipment etc. This uses energy
> regardless of whether it is identified as traffic. The otherwise really bad
> article on Base Station Energy use in Finland by prof. Manner and
> associates has some graphs that show really well how base stations use
> energy even when there is (hardly) any traffic. The difference between
> little use and some use of the equipment is 10-30%, though it is doubtful
> this is GB related, it could well be because there are users active and
> they need to be managed and slots need to be chosen for them. At least
> energy usage doesn't follow GB very well, which seems to me a strong
> indication that there is not a good correlation, because the resolution
> appears to be per 5 minutes or per hour and I would expect that at such
> large resolutions the correlation to be more smooth.
> https://ieeexplore.ieee.org/mediastore_new/IEEE/content/media/6287639/10005208/10005276/huttu11-3234192-large.gif
> and
> https://ieeexplore.ieee.org/mediastore_new/IEEE/content/media/6287639/10005208/10005276/huttu12-3234192-large.gif
> 4. Protocol and standard design: Layer 1 and 2 standards determine
> distance, modulation etc and as a result how and when transmitters and
> receivers are active or that they are active all the time. Quite alot of
> bits and bytes are headers and related to network control. They somehow
> don't feature in many calculations. Neither do we see mention of encryption
> and decryption of signals in the analysis of energy use. It would appear
> such characteristics might influence energy use. Routing, roaming etc all
> appear to have some relevance to how network equipment uses energy
> 5. Omissions of signals; In reports on energy use of consumer broadband
> networks the transmission of IP-TV or DVB-C bits, whether they use
> multicast or unicast appear to be omitted from the calculations. This is
> quite odd because those modulations make use of the same equipment and
> signals. It would also appear that including them would make the kWh/GB
> metric more favorable for those operating the networks. Similarly B2B
> traffic, roaming traffic, MVNOs etc are at times excluded from the tally of
> GB.
> 6. Computer science: The effort that is needed to process data in digital
> systems appears to be very much related to the intentions of the sender and
> receiver of those data. The intentions determine the type of network used,
> the distance covered, protocols and technologies used.The same file
> received from a CDN 20km away is different than from a server 11,000km
> away. In addition further processing is often included in calculations, but
> not well differentiated. A webpage can by plain HTML, but the same plain
> HTML can also cause all kinds of calculations based on the browser and the
> intentions of the users.
>
> Apart from theoretical the empirical data also shows the same results. In
> the presentation I gave to the students at this weeks RIPE event i showed
> some examples of stable or declining energy use in networks, where the
> amount of data transmitted did rise over the same period. This would
> suggest that in live networks there is no correlation between GB however
> defined and kWh. Furthermore so far attempts at using kWh/GB in any kind of
> extrapolation or assessment have resulted in gross imperfections. I
> included some of them in the presentation, but the way prof. Manner
> calculated the energy use of mobile data in Finland and came up with a
> figure double of fixed and mobile networks in Finland use together and
> triple that of what Finnish mobile networks report should be a clear
> indication that no scientific value can be found in the use of kWh/GB.
>
> Lunden, Bergmark and Malmoding give some early indications on how to
> assess energy use at the scale of a network and country.
> https://www.mdpi.com/2071-1050/14/5/2637?trk=public_post_comment-text
> Unfortunately that isn't the level where the IETF plays a significant role.
> However the IETF might play a role in clearly signalling that kWh/GB is a
> sure sign that the assessment of the ecological impact of the Internet will
> be incorrect in the study that uses it and that the study can most likely
> be disregarded.
>
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