Re: [8023-POEP] Classification Ad Hoc: Summary from 2-22-06
Hi all,
Please see bellow my comments for the summary.
Thanks
Yair.
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7. Before a 4-pair PSE grants power to a 4-pair PD
operating above XX watts, the PSE must first verify that all 4 pairs are
present and connected to the 4-pair PD. If the PSE only detects two
pair are present, the PSE will only grant power up to XX watts.
XX watts is the maximum power allowed in a 2-pair system. I.E., any
time the PSE wants to use all 4 pairs, it must first verify that all 4
pairs go to the same PD.
---
Yair:
Other option to consider:
-PSE is limiting the power per any 2P to XX watts.
-PSE is performing detection and classification for any 2P.
-If the PD is 2P then all is OK.
-IF the PD is 4P then each 2P will receive XX watts max. PD is
responsible to current share to utilize the max power in order not to
cause an overload condition per 2P.
The PSE is responsible to turn ON power on all 4P within TBD time (1ms
max?) only after detection and classification ended successfully done.
- IF an outlet is splitted to two separate PDs then they will be power
after PSE getting valid detection and classification data.
The purpose is to allow flexibility in application and infrastructure
utilization as long as there is no hazard to equipment and users and
there is no potential interoperability issues.
----
8. Classification is mandatory
---
Yair: We need to define if it is mandatory in PD? In PSE or both?
I guess the objective is to have in both.
------
Misc
--
Yair: See also detailed analysis in:
http://grouper.ieee.org/groups/802/3/poep_study/public/jul05/darshan_3_0
705.pdf
-------------------- End of comments ------------
-----Original Message-----
From: owner-stds-802-3-poep@xxxxxxxx
[mailto:owner-stds-802-3-poep@xxxxxxxx] On Behalf Of Clay Stanford (LTC)
Sent: Thursday, February 23, 2006 12:30 AM
To: STDS-802-3-POEP@xxxxxxxxxxxxxxxxx
Subject: [8023-POEP] Classification Ad Hoc: Summary from 2-22-06
Thanks to Steve Robbins for this summary. I have
added some to it. We can verify this list tomorrow.
Things the group seems to agree on:
1. Backward compatibility with 802.3af is required.
2. Mutual identification is required:
a. An AT-PD must be able to distinguish between AF-PSE
and AT-PSE
b. An AT-PSE must be able to distinguish between AF-PD
and AT-PD.
3. Classification power range is roughly 2W (see issue
1 below) to 100W.
4. The classification scale should be roughly
logarithmic, or log like.
a. Certainly logarithmic for high power classes
b. Probably linear for low power classes
5. Any advanced power management issues such as
negotiation, should be done with Layer 2. (Layer 2
definitions are outside the scope of this ad hoc.)
6. Layer 2 power management is optional.
7. Before a 4-pair PSE grants power to a 4-pair PD
operating above XX watts, the PSE must first verify
that all 4 pairs are present and connected to the
4-pair PD. If the PSE only detects two pair are
present, the PSE will only grant power up to XX watts.
XX watts is the maximum power allowed in a 2-pair
system. I.E., any time the PSE wants to use all 4
pairs, it must first verify that all 4 pairs go to the
same PD.
8. Classification is mandatory
9. Class policing will remain optional.
10. Classification method should support midspan and
endpoint PSEs.
Issues the group felt must be discussed further:
1. What should the low end of the power range be?
(See item 3 above.)
2. Should we use worst-case or statistical analysis to
try to calculate utilization, and the number of
classes required?
3. Should 4P verification be done during
classification or detection?
4. Should the PD have one signature (visible on all 4
pairs) or 2 separate signatures (one on Alt-A and the
other on Alt-B)?
5. Should 4-pair systems be treated as two autonomous
2-pair systems?
6. Should a 4-pair PD that fails to get power provide
user with a two-level failure indication, one for an
AF-PSE and another for a 2-pair AT-PSE?
7. How many classes should be provided?
Subjects for Future Discussions
Power supply utilization
Misc
Yair provided a Preliminary Comparison Table.
Yair referenced a previous work on power supply
utilization
http://grouper.ieee.org/groups/802/3/poep_study/public/jul05/darshan_2_0
705.pdf
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