[WIMS] Should IETF EMAN register PWG power states? - No

[WIMS] Should IETF EMAN register PWG power states? - No

[WIMS] Should IETF EMAN register PWG power states? - No

William Wagner wamwagner at comcast.net
Tue Aug 16 17:57:35 UTC 2011

Note that this item relating to registering the PWG Imaging System Power MIB
power state set with IANA for reference in the IETF eman Energy Monitoring
MIB is on the agenda for the WIMS concall the Wednesday at 1PM EDT. 


For those who have not been following the IETF eman list (and it is very
active), there are three recent documents of interest. All of these are
revisions of earlier documents, and all have been subject to extensive
comment, so nothing in them is necessarily firm.


http://tools.ietf.org/html/draft-ietf-eman-requirements-04 (July 11, 2011)

http://tools.ietf.org/html/draft-ietf-eman-framework-02 (July 8, 2011)

http://www.ietf.org/id/draft-ietf-eman-energy-monitoring-mib-00.txt (Aug 5,


My understanding is that, although there was a drive for a simple,
consistent power state set, it was recognized that:

a.     Several such sets were already defined (e.g., IETF 1621 and DMTF, and
also ACPI which both the PWG and eman seem to  prefer to avoid)

b.     Certain types of devices have power states that are traditional and,
in many cases most appropriate to the nature of those type of devices.

So, the conclusion was that a device in implementing the eman mib could
identify the power state set it was using as either the eman defined state
or an allowed IANA registered power state set. The current eman energy
monitoring MIB  allows devices to identify the power states set as IETF
1621, DMTF or EMAN.


Because the PWG has sought to keep the eman group aware of the fact that
hardcopy equipment has a significant energy use contribution (Randy recently
observed that "multi-function peripherals (high duty-cycle printer, copier,
fax, scanner products) consume an order of magnitude more power than any
switch or router") and that there was an approved Imaging System Power MIB
with a power state set appropriate to these devices, the current draft of
the eman energy monitoring MIB asks whether the PWG Power State Set
(provided that it is EMAN registered) be allowed. This would  allow the PWG
Power State Set (which although derived from the DMTF, does provides for
vendor extensions) to be used in responses to eman MIB queries. With regard
to the "tail wagging the dog comment", although it may require management
applications to recognize the PWG set, it would not require not have any
effect on devices that which to use a different power state set.


Considering that hardcopy devices may well be implementing both the PWG and
the eman MIBs, I join with Ira in requesting that the industry give issue
consideration. It is not often that the infrastructure groups of the  IETF
recognize that hardcopy devices are more than little peripherals attached to



Bill Wagner -CoChair, WIMS/PMP


From: wims-bounces at pwg.org [mailto:wims-bounces at pwg.org] On Behalf Of Ira
Sent: Thursday, August 11, 2011 11:48 AM
To: wims at pwg.org; Ira McDonald
Subject: [WIMS] Should IETF EMAN register PWG power states? - No



ACTION - All - Read and comment on this power states issue for EMAN.

The latest draft of the IETF EMAN Energy Monitoring MIB (monitor-only
subset of EMAN model) includes the following issue:

        "OPEN ISSUE 12: Consideration of IEEE-ISTO PWG in the IANA list 
        of Power State Set ? PWG Imaging Systems Power Management MIB 

And Bruce Nordman (EMAN co-chair) raised the question of registering the
PWG power states with IANA for EMAN last week at the PWG meeting 
- I waffled in my reply.

On reflection, I propose that the PWG does NOT register their own power
states (adding significant complexity to the NMS systems that will already
support the other three standard power state sets).

Instead, best practice would be for PWG Power MIB enabled devices to
*fold* vendor extension states into their base DMTF power states (already
in EMAN) for more coherent power monitoring and power management
across the enterprise.  This folding would have to occur anyway for a DMTF
CIM mapping of the PWG Power Model, so we'd be consistent for "outside"


- Ira

PS - I'd like to reply on the IETF EMAN mailing list within the next two
on this issue - please send your opinions.

Ira McDonald (Musician / Software Architect)
Chair - Linux Foundation Open Printing WG
Chair - TCG Embedded Systems Hardcopy SWG
IETF Designated Expert - IPP & Printer MIB
Blue Roof Music/High North Inc
mailto:blueroofmusic at gmail.com
Christmas through April:
  579 Park Place  Saline, MI  48176
May to Christmas:
  PO Box 221  Grand Marais, MI 49839


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