# Re: [802.3_4PPOE] End to End Channel Pair to Pair Unbalance Ad Hoc Presentation

Hi Wayne,

This solution, filters the "unrealistic use cases" that were resulted from short cables.

How it helps?

If we set a limit for the channel for 7%, and a user did use cabling and connectors combinations that is considered "not typical use case" or even "not realistic use case" and he got 12% it will be an issue for him. The spec says A and he got B.

This filters all the results of B which are not relevant to him when the channel is tested as standalone part.

The justification for this approach is, when the channel is connected to a system, and the channel uses short cables, the End to End current/resistance unbalance will be dominant since their unbalance is higher than the channel.

This is one of the solutions from the table.

There is 5th solution that in after our adhoc meeting Sterling and I were discussing and I am working on its details.

Regards

Yair

From: Larsen, Wayne [mailto:WLARSEN@xxxxxxxxxxxxx]
Sent: Thursday, July 03, 2014 6:09 AM
To: Darshan, Yair; STDS-802-3-4PPOE@xxxxxxxxxxxxxxxxx
Subject: RE: [802.3_4PPOE] End to End Channel Pair to Pair Unbalance Ad Hoc Presentation

Hi Yair,

You showed a spreadsheet of four possible solutions, and one of them was to measure the DC resistance unbalance of the cabling channel with resistors in series with it.

What is the problem these solutions are solving?

Wayne

7/2/14

From: Darshan, Yair [mailto:YDarshan@xxxxxxxxxxxxx]
Sent: Wednesday, July 02, 2014 7:15 PM
To: Larsen, Wayne; STDS-802-3-4PPOE@xxxxxxxxxxxxxxxxx
Subject: RE: [802.3_4PPOE] End to End Channel Pair to Pair Unbalance Ad Hoc Presentation

H Wayne,

Your question Is not clear to me can you elaborate?

Yair

From: Larsen, Wayne [mailto:WLARSEN@xxxxxxxxxxxxx]
Sent: Wednesday, July 02, 2014 11:38 PM
To: STDS-802-3-4PPOE@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_4PPOE] End to End Channel Pair to Pair Unbalance Ad Hoc Presentation

Hi Yair,

I was trying to ask, what problem is being solved by this?

Wayne

7/2/14

From: Jeff Heath [mailto:jheath@xxxxxxxxxx]
Sent: Wednesday, July 02, 2014 11:25 AM
To: STDS-802-3-4PPOE@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_4PPOE] End to End Channel Pair to Pair Unbalance Ad Hoc Presentation

Please announce when and why the ‘formal meeting’ has ended in the future.

Regards,

 Jeff Heath Design Center Manager paper: 402 East Carrillo Street, Suite D Santa Barbara, California 93101 voice: 805.965.6400 fax: 805.965.1701 computer:

From: Darshan, Yair [mailto:YDarshan@xxxxxxxxxxxxx]
Sent: Wednesday, July 02, 2014 9:00 AM
To: Jeff Heath; STDS-802-3-4PPOE@xxxxxxxxxxxxxxxxx
Subject: RE: [802.3_4PPOE] End to End Channel Pair to Pair Unbalance Ad Hoc Presentation

I meant that we continue to discuss after the time of the forma meeting. The formal meeting ends when there is not sufficient attendees or someone ask to finish on time, or most of the group agrees to continue, so after that time we can continue discussion whit out having decisions.

Yair

From: Jeff Heath [mailto:jheath@xxxxxxxxxx]
Sent: Wednesday, July 02, 2014 6:16 PM
To: Darshan, Yair; STDS-802-3-4PPOE@xxxxxxxxxxxxxxxxx
Subject: RE: [802.3_4PPOE] End to End Channel Pair to Pair Unbalance Ad Hoc Presentation

What do you mean by formal ad hoc meeting?

Regards,

 Jeff Heath Design Center Manager paper: 402 East Carrillo Street, Suite D Santa Barbara, California 93101 voice: 805.965.6400 fax: 805.965.1701 computer:

From: Darshan, Yair [mailto:YDarshan@xxxxxxxxxxxxx]
Sent: Wednesday, July 02, 2014 3:53 AM
To: Jeff Heath; STDS-802-3-4PPOE@xxxxxxxxxxxxxxxxx
Subject: RE: [802.3_4PPOE] End to End Channel Pair to Pair Unbalance Ad Hoc Presentation

Thanks Jeff.

I am working on this direction too and few others that we discuss after the formal 1 hour time of the adhoc meeting.

Yair

From: Jeff Heath [mailto:jheath@xxxxxxxxxx]
Sent: Tuesday, July 01, 2014 7:53 PM
To: STDS-802-3-4PPOE@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_4PPOE] End to End Channel Pair to Pair Unbalance Ad Hoc Presentation

Yair,

The entire principle of adding balanced resistance to test imbalanced channel resistance does not represent any real system.  PSE PI and PD PI will add imbalance in worst case analysis.  At the end of the day only full worst case analysis using all three components will give us the correct worst case maximum current

Regards,

 Jeff Heath Design Center Manager paper: 402 East Carrillo Street, Suite D Santa Barbara, California 93101 voice: 805.965.6400 fax: 805.965.1701 computer:

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