Subject: Re: [eman] New Version Notification for draft-parello-eman-definitions-03.txt

From: Juergen Quittek <[email-masked]>
Date: Sun, 6 Nov 2011 13:34:34 +0000

Hi John,

I have two comments/questions about your concept of energy object
relationships.  I found explanations of the general concept in
draft-ietf-eman-framework-03 (section 5.3 and last paragraph of section
4).  For the different kinds of relationships, I only found terminology
entries in draft-parello-eman-definitions-03 but no further descriptions.

1. You define a Power Source Relationship:
   > An Energy Object may be the source of or distributor of
   > power to another Energy Object(s) and is referred to as
   > a Power Source Relationship.
   > 
         
   > NOTE: An Energy Object may be powered by another
   > Energy Object(s).
   > 
   > Reference: herein
   > 
         
   > Example: a PDU provides power for a connected host.

This implies that every PDU supplying other devices with power has a power
source relationship, even if it does not at all has any reporting or
control function.  A plain light switch is has this relationship to the
switched light bulb.  In such a case neither endpoint of the relationship
(provider, receiver) nor the EnMS must have any knowledge of the
relationship.  Is this correct?

A similar case is a PDU measuring power at its outlets.  It may be able to
report power at outlet #5 to a management system but without knowing which
EO(s) are supplied via outlet #5. According to your definition, it has a
metering relationship to the supplied EO(s) even without knowing them and
maybe without the supplied EO(s) knowing about the relationship.  And the
management system may or may not know about the relationship.  Also
correct?

2. My second question relates to a scenario with three EOs: A PC, a power
meter, and a switch.  In one of the scenarios you discussed, the switch
may act as parent of the PC and report power state and power on behalf of
the PC.  Now I see the following relationships:
   a. The switch gets power state info from the PC and reports it.
      This is a proxy relationship between switch and PC.
   b. The meter measures power at one of its outlets without knowing
      which other device (the PC) is connected.
      This is a metering relationship between meter and PC.
   c. The switch gets meter readings from the meter and has indications
      that the meter reading shows the power consumption of the PC.
      Now the switch reports the meter reading from one of the outlets
      of the meter as power value for the PC.
      What is the relationship here? Apparently, there is not metering
      relationship between switch and PC because the switch does not
meter. 
      Is it a proxy relationship?

Thanks,

    Juergen

On 26.10.11 20:12, "John Parello (jparello)" <[email-masked]> wrote:

>HI,
>
>I have posted a new revise version based on feedback from the group.
>Various edits in the definition and refinements.
>
>Diffs are here:
>http://tools.ietf.org/rfcdiff?url2=draft-parello-eman-definitions-03
>
>Please do review this new draft and I welcome your comments and
>additions.
>
>http://www.ietf.org/id/draft-parello-eman-definitions-03.txt
>
>Thanks
>Jp
>
>
>
>_______________________________________________
>eman mailing list
>[email-masked]
>https://www.ietf.org/mailman/listinfo/eman

---

From: Juergen Quittek <[email-masked]>
Date: Sun, 6 Nov 2011 20:43:29 +0000

Hi John,

I have another comment on the EO relationships.

> Proxy Relationship
> 
> An Energy Object that provides Energy Management capabilities on
> behalf of another Energy Object so that is appears to be Energy
> Aware is referred to a Proxy Relationship.

What does it mean "so that it appears energy aware"?

1. If a PoE switch reports power values on a non-aware desktop
phone, this does not make the desktop phone appear to be energy
aware, because it is the switch and not the other device
Reporting the values.
The only way to make it appear energy aware would be the switch
sending power values with the source IP address of the desktop
phone. Then indeed the phone would appear to be energy aware.
Do you really mean this?

2. There may be proxies that do not want to make the other energy object
on which they report energy aware.  A proxy reporting on a plain light
Would have no reason to make the lightbulb appearing to be energy aware
when everyone knows it is not.

My proposal is to replace "so that is appears to be Energy Aware"
in the definition of the proxy relationship.  A good replacement
candidate might be "by providing monitoring or control functions
for this EO".  But the correct replacement depends on what is
Your idea of this relationship.

Thanks,

    Juergen

---

From: "John Parello (jparello)" <[email-masked]>
Date: Sat, 12 Nov 2011 11:18:58 -0800

Hi JQ

See inline...

-----Original Message-----
From: Juergen Quittek [mailto:[email-masked]] 
Sent: Sunday, November 06, 2011 12:43 PM
To: John Parello (jparello); eman mailing list
Subject: Re: [eman] New Version Notification for
draft-parello-eman-definitions-03.txt

Hi John,

> behalf of another Energy Object so that is appears to be Energy Aware 
> is referred to a Proxy Relationship.

[jp] That was a left over from previous draft. Thanks for catching it.
Will be removed.

1. If a PoE switch reports power values on a non-aware desktop phone,
this does not make the desktop phone appear to be energy aware, because
it is the switch and not the other device Reporting the values.
The only way to make it appear energy aware would be the switch sending
power values with the source IP address of the desktop phone. Then
indeed the phone would appear to be energy aware.
Do you really mean this?

[jp] I see no reason to exclude that.  So yes that's a proxy. A switch
or any power distributing device could create a proxy and report the
power values as though it we coming from the end device along with the
outlet. Especially in cases where that device may not be on an IP
network and the device has means to ask the endpoint via another
protocol. In your case the PoE device had an IP address but that may not
be the case. So a device proxying another (it reports the outlet and the
device power) is a valuable modeling and management scheme. We have
quite a number of products that do this along with partner product which
to the same as "gateways"

My proposal is to replace "so that is appears to be Energy Aware"
in the definition of the proxy relationship.  A good replacement
candidate might be "by providing monitoring or control functions for
this EO".  But the correct replacement depends on what is Your idea of
this relationship.

[jp] agree. Again sorry the aware was left over. 

Jp

---

From: "John Parello (jparello)" <[email-masked]>
Date: Sat, 12 Nov 2011 11:29:31 -0800

Hi JQ,

Thanks please see inline...

-----Original Message-----
From: Juergen Quittek [mailto:[email-masked]] 
Sent: Sunday, November 06, 2011 5:35 AM
To: John Parello (jparello); eman mailing list
Subject: Re: [eman] New Version Notification for

Hi John,

entries in draft-parello-eman-definitions-03 but no further
descriptions.

         
   > Example: a PDU provides power for a connected host.

This implies that every PDU supplying other devices with power has a
power source relationship, even if it does not at all has any reporting
or control function.  A plain light switch is has this relationship to
the switched light bulb.  In such a case neither endpoint of the
relationship (provider, receiver) nor the EnMS must have any knowledge
of the relationship.  Is this correct?

[jp] I think I followed your comment it was a bit unclear but let's see.
In the case of an electrical switch and ordinary light bulb does the
bulb  have a powered by relationship to the switch. I see no reason why
this could not be modeled in an EnMS using that relationship. So yes.
Whether that relationship was learned from the devices, the EnMS or a
human entering the information is immaterial I think. So yes but
tentative on me following your question.
 
A similar case is a PDU measuring power at its outlets.  It may be able
to report power at outlet #5 to a management system but without knowing
which
EO(s) are supplied via outlet #5. According to your definition, it has a
metering relationship to the supplied EO(s) even without knowing them
and maybe without the supplied EO(s) knowing about the relationship.
And the management system may or may not know about the relationship.
Also correct?

2. My second question relates to a scenario with three EOs: A PC, a
power meter, and a switch.  In one of the scenarios you discussed, the
switch may act as parent of the PC and report power state and power on
behalf of the PC.  Now I see the following relationships:
   a. The switch gets power state info from the PC and reports it.
      This is a proxy relationship between switch and PC.

[jp] IF the switch were reporting on behalf of the PC then proxy. If the
switch was merely communicating the value for the PC then aggregation. 

   b. The meter measures power at one of its outlets without knowing
      which other device (the PC) is connected.
      This is a metering relationship between meter and PC.
[jp] Yes the meter of the outlet could be a meter for the PC as well,

[jp] That got confusing so I didn't follow that. The switch "gets" the
reading? Was it proxy or just asked for it via protocol. Let's talk this
one out a bit. I think you have a specific case here in mind.

[jp] In general on relationships, the scheme allows for some complex
modeling so to use a crass analogy it's like family relationships. Can a
parent be both a father and uncle. Yes. Can it be pointed out as odd.
Yes. Is it valid yes. 

[jp] HTH and let's explore your last case a bit more.

Jp

Thanks,

    Juergen