[irtf-discuss] Re: Network Equipment Energy Efficiency Metric

[Marie-Jose Montpetit <[e-mail]>]

I think any metric should also take into account the type of energy that is being used.  This is common in how the cost is evaluated in energy audits and there are companies who do that.  So essentially a “bit” produced on a system that uses a gas powered evergy source has not the same value a a bit produced under a wind power. 

mjm
Marie-José Montpetit, Ing. Ph.D.
[e-mail]





> On Nov 11, 2024, at 3:13 PM, Hesham ElBakoury <[e-mail]> wrote:
> 
> 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?