[irtf-discuss] Network Equipment Energy Efficiency Metric

[Hesham ElBakoury <[e-mail]>]

Dean and Tony presented set of metrics in the GREEN WG meetings one of them
is *Network Equipment Energy Efficiency* metric. I think this is the the
kWh/GB  metric which although it is used, we debated it for quite sometime
in e-impact.

I recall that Rudolf calls this metric nonsense and should be banned,
because "it doesn't convey any comparable and actionable meaning. The
numbers are incomparable because traffic and energy use are in no way and
have never been related. How is it possible that with the exact same
network and equipment the energy use is stable when traffic goes up?"

The Journal of Industrial Ecology
<http://davidmytton.blog/?action=user_content_redirect&uuid=26a31a773b7bba39c75caf0de4d5c5b2044163406de0898dfdfa2c769ab31970&blog_id=140180607&post_id=4707&user_id=244835025&subs_id=408283364&signature=6485fa34baff8ccaeb16b8eaf6822554&email_name=new-post&user_email=[e-mail]&encoded_url=aHR0cHM6Ly9vbmxpbmVsaWJyYXJ5LndpbGV5LmNvbS9qb3VybmFsLzE1MzA5Mjkw>
 published
a new paper co-authored by Dag Lundén and Jens Malmodin.  Paper Title: Network
energy use not directly proportional to data volume: The power model
approach for more reliable network energy consumption calculations
<http://davidmytton.blog/?action=user_content_redirect&uuid=85c1e5d13df5d1118d082181ed00f6e7a5ed7a2046c0eb8de4b50f9fb0af4d12&blog_id=140180607&post_id=4707&user_id=244835025&subs_id=408283364&signature=51744c392cee5b2ee750ad1c052559d5&email_name=new-post&user_email=[e-mail]&encoded_url=aHR0cDovL2RvaS5vcmcvMTAuMTExMS9qaWVjLjEzNTEy>
.

The idea in this paper is that many modelers have assumed a linear
relationship between data volume and energy consumption. This fails to
account for idle power consumption and other factors. Also, networks are
typically too complex to model its energy efficiency with a number as
simple as joules/bit. This paper suggests the Power Model which has its
limitations.

The main conclusion of the paper is that
 "There is now sufficient evidence from many organizations from a range of
different geographies to demonstrate the lack of a connection between
network usage and total energy. Combining this with a commonsense approach
that total energy of a network device cannot exceed the total maximum power
of that device and an understanding of how networks are provisioned for
redundancy and peak capacity proves that network energy use is not directly
proportional to data volume"

Over the years we have seen many publications offering their ideas and
suggestions for energy efficiency metrics, but they have their flaws and
shrotcomings. I doubt there is a "perfect" metric for systems as complex
and multifaceted as a communications network.

Comments?