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Re: [8023-POEP] Baseline Bucket ad hoc



Yair,
 
At the last meeting you mentioned that you had tested 100BASE-T with inline power on the data pairs and found no problems. During an offline discussion, we discussed performing testing with maximum length cables and the "Killer Packet" to ensure that your testing did not miss the impact of baseline wander on your testing. To assist, I sent you a copy of the Killer Packet (zipped binary) to enhance your testing.
 
Have you had an opportunity to evaluate the impact of inserting power into the data pairs using the Killer Packet since our discussion and do you plan to present on this?
 
I think it would be important to ensure that we fully characterize the exposure of inserting any additional low-frequency poles into the channel on 100BASE-T signal impairments.

Thanks,

Dan


From: owner-stds-802-3-poep@IEEE.ORG [mailto:owner-stds-802-3-poep@IEEE.ORG] On Behalf Of Darshan, Yair
Sent: Monday, January 07, 2008 1:37 AM
To: STDS-802-3-POEP@LISTSERV.IEEE.ORG
Subject: Re: [8023-POEP] Baseline Bucket ad hoc

Hi Matt,

 

Probably you didn’t see my email which I ask not to have meetings on Friday. Friday and Saturday are a non working days here like Saturday and Sunday' in North America.

Any way, please find below my comments/opinion regarding the base line bucket:

 

Comment #141:

Comment #141 deals with "Range of Maximum power used by the PD".

The commenter state that this column has no value and I disagree with him.

This column has value in which it specifies the range of maximum for better power management.

It is true that when you are using L2 you may not need this information however when using only L1, this information has value.

 

Regarding the argument that it confuses the average reader with the minimum power required to keep the port ON, I don’t see how it confused since the text is clear and if it still confuse we can add clarification but it is not justifying changing the level of information contained in this column.

 

I suggest rejecting this comment or ad clarification for the use of it in respect to 33.3.6.

 

Comment #124:

 

The commenter is basing his argument on the following assumptions:

  1. The existing PD detection section requires specific design requirements that are not necessary to ensure interoperability: This is not accurate statement. All the requirements in the specification are a result of extensive analysis and tests. Each of the requirements came to ensure interoperability.

The change it or modify it we need to td feasibility and economical tests/simulations. Non of it has been shown or demonstrated. 

  1. Pointing out to presentation made in September 2005: This presentation was "rejected in principle" by the audience at that meeting since it failed to accommodate false positive detection due to the time constant issue. Specifically, the standard recommend to take measurements after 5tau=1% of steady state in order to reduce the chance for false positive detection. So this presentation is a good example for what we should not do. There are other detection concepts that were discussed such as capacitor detection, AC coupled diode and other and the resistor concept was chosen as the preferred one which meets all objectives at low cost and high reliability.
  2. Figure 33-10 is no the PD model so it is not clear why it is related to detection issues as stated in the Suggested Remedy.
  3. Requiring PSE to detect values of Rpd_d for all permissible values of Cpd_d as specified in Table 33-2 is not practical and it is not required by the standard today. It adds unnecessary burden to the implementers with increased time constant problems.

Rational:

The current specification required to meet Rpd_d together with Cpd_d<0.15UF. This is possible and proven feasible.

Requiring meeting Rpd_d with Cpd_d>>0.15UF is technically problematic due to long time constants and false positive detection risks. There is a way to overcome this problem by using ac signals with source and sink capabilities however it requires technical and economical feasibility tests which if somebody present such it will be easier to consider and asses its technical and economical aspects.

  1. To delete the requirement of two point detection it requires to show that you can detect Rsig with out errors within single measurement. This is not an implementation issue. It is clear interoperability issue. If somebody can technically and economically prove that it can be done in other ways he is welcome.

 

I suggest rejecting this comment unless serious technical work will be presented to backup the changes suggested.

 

Comment #13:

 

This comment is similar in principle to comment #124.

Figures 33-8 and 33-9 are not mandating implementations.

It guarantees interoperability.

Figure 33-8:  

  1. Zsource>45K: Limiting energy backwards to PSE.
  2. Zsource>45K : Preventing 25K signature if two PSEs are connected together
  3. Vdetect and Zsource>45K allows meeting 30V open loop and 2.8-10V during valid signature with adequate resolution
  4. D1: Prevents two PSEs connected together in opposite voltage polarity to generate 25K signature
  5. D1: Prevents two PSEs connected together in opposite voltage polarity to generate 120V on the port/chips.

 

Figure 33-9:  

  1. Zsource not limited, with series diode D2: Limiting energy backwards to PSE.
  2. D1: Prevents two PSEs connected together in opposite voltage polarity to generate 25K signature
  3. D1: Prevents two PSEs connected together in opposite voltage polarity to generate 120V on the port/chips.

 

      The implementer can use any Thevenin equivalent of figures 33-8 or 33-9 which allows the flexibility which we are looking for.

 

In order to allow such big changes it is requires proving feasibility with different PSEs using different methods complying to the suggested remedy……!!!

 

Unless such proofs made I suggest to reject this comment.

 

 

Yair

 

  

 

 

 

 


From: owner-stds-802-3-poep@IEEE.ORG [mailto:owner-stds-802-3-poep@IEEE.ORG] On Behalf Of D. Matthew Landry
Sent: Friday, January 04, 2008 4:16 PM
To: STDS-802-3-POEP@LISTSERV.IEEE.ORG
Subject: Re: [8023-POEP] Baseline Bucket ad hoc

 

Please find attached material for discussion during this morning's baseline bucket ad hoc.

Note in the meeting notice below, the 11:00AM starting time is Central Standard Time.


-matt

On Dec 11, 2007 11:53 AM, D. Matthew Landry < dmlandry@ieee.org> wrote:

Colleagues -

This message is announcing a comment resolution adhoc to discuss the remaining comments classified in the baseline bucket. This meeting will be administered by teleconference. Required materials will be sent prior to commencement of the meeting. The bucket of comments can be found at the following URL:

http://www.ieee802.org/3/at/comments/D1.0/P802d3at_D1p0_postmtg_bucket_baseline.pdf

Please take some time to review the IEEE-SA PatCom slides prior to the start of the telecon. I will ask if anyone has not reviewed the slides at the beginning of the call. If any attendees indicate that they have not reviewed the slides, time will be made available for such review. The slideset can be found at the following URL:

http://standards.ieee.org/board/pat/pat-slideset.pdf

The dial-in information is found at the end of this email. If you plan to attend, I ask that you RSVP  no later than the day before so that I can ensure that enough dial-in slots are available.

Thank you.

- matt


TELECONFERENCE DETAILS

Subject:
    IEEE 802.3at baseline bucket
Meeting ID:
    802302
Date/time:
    01/04/2008, 11:00 AM (US: Central (CST/CDT))
    01/11/2008, 11:00 AM (US: Central (CST/CDT))
Duration:
    1 hrs 30 minutes
Dial-in:
    International:
1.512.532.5999
    USA: 1.866.781.8274