Subject: [eman] Comments on eman framework-02

From: JinHyeock Choi <[email-masked]>
Date: Thu, 14 Jul 2011 16:02:22 +0900

Dear John and all

thanks for the update and here are my comments.

1. Terminology
Currently eman documents (such as requirement & framework)
use different terminologies, for example ‘powered entity’ for requirement
and ‘Energy Managed Object’ for framework. I’m worried that
inconsistent terminologies would bring forth misunderstanding.
(As we know, anything that can confuse will.)
I ask the authors would decide on some common terms.

2. Energy control protocol
What is the protocol of choice for energy control?
For energy monitoring, SNMP (and, maybe IPFIX) is the one.
Which protocol will we use for energy control
such as modifying power state? Also SNMP?

3. EnMS communication peer
It may be better to define an entity with which EnMS communicates
for energy monitoring (or energy control).

For example, when EnMS monitors an EMO’s energy consumption,
from which entity will EnMO get the information (via SNMP)?
The communication peer may or may not be the EMO itself.

The entity should have access to the EMO’s energy information
and be able to report the information to EnMS (i.e IP aware).
Currently it’s described as if EnMO talks with EnMO’s parent,
which may not have the above capacity.

Reference-01 defined the term ‘Power monitor’ 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.

which may be useful.

4. The Parent for a Children’s Energy management
Parent & Children relationship is determined by aggregation,
metering, power source, proxy and dependency capabilities.
So a Children may have multiple Parents.
Among them, which one would be involved in Energy management,
specifically energy monitoring & control?
A Parent with Proxy relationship?

Here are some more.

> 1. Introductioon
>
> The identified device can then be monitored for Energy

I propose to
sub ‘monitored for enegy’ with ‘monitored directly or indirectly for Energy’
for clarification.

> 3. Terminology
>
>
> Energy Management System (EnMS)

Is abbreviation for Energy Management System
EnMS or EMS?

In below, EMS is also used.

> An Energy Management System (EMS) is congruent to a Network

EnMS or EMS?

>        Energy Monitoring
>
>        Energy Monitoring is a part of Energy Management that deals with
>        collecting or reading measurements from devices to aid in Energy
>        Management.  This could include Energy, Power, Demand, Quality,
>        Context and/or Battery information.
>        Energy

The last ‘Energy’, typo?

>        Demand
>
>        Demand is an average of Power measurements over an interval(s)
>        of time and typically expressed in kilowatt hours.

Is ‘Demand’ represented by kilowatt hours,
even when it’s an average power value (represented by watt)?

>        Energy Aware Object
>
>        An Energy Managed Object may not have the capability to provide
>        information necessary for Energy Management itself. If an Energy
>        Managed Object can provide Energy Management Context, Energy
>        Monitor and optionally Energy Control values for itself then the
>        Energy Managed Object is said to be an Energy Aware Object

Does ‘can provide’ mean the EMO is able to communicate with EnMS?
What if an EMO can measure it’s energy consumption but is not IP-aware?

Also does ‘Energy Awareness’ only concern about itself?

>     4. Energy Management Reference Model
>
>        As displayed in the Figure 2, a more complex energy reference
>        model includes Energy Managed Object Parents and Children.  The
>        Energy Managed Object Parent returns information for themselves
>        as well as information according to the Energy Managed Object
>        Relationships.

Not all Parent can return information for their Children.
Only a Parent with the Children’s energy information and SNMP module can.
A power source may be a non-IP device.

>     5.4. Energy Monitoring
>
>        Each Energy Managed Object will have information that describes
>        Power and Energy information along with how that measurement was
>        obtained or derived.

Not all EMO has its own energy-related information.

With the term of ‘power monitor’, we may rephrase this as

    Each Power Monitor (possibly Proxy Parent)
    associated with an Energy Managed Object,
    will have the information of the EMO that describes.....

>        Power Measurement
>
>        In addition, the Energy Managed Object should describe how it
>        intends to measure Power as one of consumer, producer or meter
>        of usage.  Given the intent readings can be summarized or
>        analyzed by an EMS.  For example metered usage reported by a
>        meter and consumption usage reported by a device connected to
>        that meter may naturally measure the same usage.  With the two
>        measurements identified by intent a proper summarization can be
>        made by an EMS.

With this differentiated power measurement,
one EMO (such as PoE switch) can have multiple energy values,
for example one as a consumer and another as a provider.
The concept of ‘power interface (inlet & outlet)’
proposed in reference I-D may be of help.

>     5.5. Energy Control
>
>        Energy Managed Objects can be controlled by setting it to a
>        Power State. Sets of Power States can be seen as an interface by
>        which an Energy Managed Object can be controlled.

With which protocol will EnMS set power state? SNMP?

>        When and individual Power State is configured from a specific

typo, sub ‘and’ with ‘an’

thanks for your kind consideration.

Best regards

JinHyeock