Subject: [eman] new reference model based on power interfaces

From: Juergen Quittek <[email-masked]>
Date: Tue, 12 Jul 2011 14:28:18 +0000

Dear all,

Just before the deadline Bruce and I posted a new version -02 of the
reference model for energy management. Please find it at
http://datatracker.ietf.org/doc/draft-quittek-eman-reference-model/

The previous version -01 was based on boxes and functions. It was much about
which service is provided where. The result was a long list of new terms
such as power state monitor and power supply controller. The resulting model
was usable for explaining the things we want to do in eman, but big and
complex. Also the model in the framework document does not seem to be simple
and Internet-style.

That's why there is an entire new model in the new version -02 of the
reference model draft which is much simpler and much closer to existing IETF
concepts.

The new model is very short and is based on the concept of power interfaces.
We see power interfaces as very similar to network interfaces. They connect
a device to a shared (power) transmission medium, the power line. A power
interface can be in mode inlet or outlet and it may have metering
capabilities. Finally, it can (if available) provide information on other
devices connected to the same medium. This is already almost all that is
needed. 

We call a device with one or more power interfaces in inlet mode a powered
entity (PE), and a device with one or more power interfaces in outlet mode a
power source (PS). If there is metering capability, we call it a power meter
(PM).  No more terms are needed!

The concept of a power interface has been adopted from the Power over
Ethernet specification where powered devices (PDs) and power sourcing
equipment (PSE) are connected to shared transmission media via power
interfaces.

Integration of energy management into existing NMS systems becomes much
simpler than with models we discussed before, because the concept is very
similar to the concept of network interfaces and thus similar structures in
MIB modules and NMS systems can be used. Also a MIB module according to the
new model would become much simpler than the ones we already have.

If you still want to compare it to the previous model, you will find it in
the Appendix of the new draft (that's why it is so long).

Unfortunately, time was not enough to fully explain all details of the new
model sufficiently. We will update the draft soon with full explanations.

Of course, comments are highly appreciated.

Thanks,

    Juergen

---

From: JinHyeock Choi <[email-masked]>
Date: Thu, 14 Jul 2011 18:15:11 +0900

Juergen

thanks for your trouble for the update.

The concept of power interface is of interests and
make me see in a new perspective.

Here are some quick comments.

1. Power monitor

> (PM). No more terms are needed!

We don’t even need the term ‘Power Monitor’ defined as below?

  A power monitor has access to energy-related information concerning
  powered devices and is able to report this information to energy
  management systems.

For monitoring, we should be able to
i) measure energy value (such as power state) and
ii) report the value to Energy Management System (EMS).

The above two can be performed by separate entities,
for example, power value measured by power meter,
then reported by home gateway to EMS.

PM may have the the first capacity but not always the second.
IMO, the term ‘power monitor’ is of help.

We may define ‘power controller’ similarly for power control.

2. Required information
Requirement I-D defines required information in Sec 5
such as general information, power state, power & energy.

Is there an entity to
i) keep all required information &
ii) report to EMS?

In the current draft,
PM can measure (actual) power & energy consumption for a PE
but may have no idea about the PE’s power state.
Which entity would collect energy consumption
& power state information to report to EMS?
Or the PM and PE make EMS a separate report?

Finally I wish this draft would be alighted with framework-02.
(I had assumed the I-D would be merged with the framework.)
Both I-Ds treat the same area (reference & information model)
but with substantial difference. For example, here
Energy Management Domain or Context is hardly mentioned
in information model.

Thanks for your kind consideration.

Best regards

JinHyeock

On Tue, Jul 12, 2011 at 11:28 PM, Juergen Quittek <[email-masked]> wrote:
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