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Re: Unified PMD vs. Unified PHY


Thank you for the explaination.  I am sure, given your justified desire to
reduce the number of PMDs that you will continue with the iterations of the
survey at the next meeting.

Thank you,
Roy Bynum

----- Original Message -----
From: Jonathan Thatcher <jonathan.thatcher@xxxxxxxxxxxxxxxxxxxx>
To: <stds-802-3-hssg@xxxxxxxx>
Sent: Monday, March 13, 2000 5:04 PM
Subject: RE: Unified PMD vs. Unified PHY

> Roy,
> There are a rather large number of reasons why I did not extend the
> selection set in the first question. Primarily, it has to do with the fact
> that a 2-dimensional question like the one I asked is already
> challenging. To have made this a 3-dimensional question would have made
> in my mind, unanswerable. There are ways to take 3-dimensional questions
> reduce them to 2-dimensions, but to do this correctly requires several
> iterations of questions to confirm the many assumptions that are made to
> so. Without having the time to go through these iterations would have
> me to impose my own interpretation upon the question, thus breaking all
> rules of conducting this type of survey.
> jonathan
> > -----Original Message-----
> > From: owner-stds-802-3-hssg@xxxxxxxx
> > [mailto:owner-stds-802-3-hssg@xxxxxxxx]On Behalf Of Roy Bynum
> > Sent: Sunday, March 12, 2000 11:50 AM
> > To: Jonathan Thatcher
> > Cc: stds-802-3-hssg@xxxxxxxx
> > Subject: Unified PMD vs. Unified PHY
> >
> >
> >
> > Johnathan,
> >
> > I was intending to ask you why you did not ask about unified PMDs
> > separate from a unified PHY as part of your survey but did not get a
> > chance.  At the 10GEA technical meeting you were very adamant about
> > getting consensus for a small set of PMDs.  I agree that having a small
> > group of PMDs is preferable.  Having a unified PHY in order to have a
> > small set of PMDs may not be preferable.
> >
> > The cost of the unified PHY, as presented, so far has been very high in
> > the form of lost transfer rate.  As it is, the unified PHY, as
> > presented, does not meet the objective to have a 10.000 Gigabit MAC
> > data transfer rate (Gb-Mtr).  Separate PHYs, LAN and WAN do meet the
> > objectives.  Additionally, one of the scramble encoded WAN PHY
> > presentations was able to achieve an average 10.000 Gb-Mtr transfer rate
> > by using IPG compression, which can be inferred to meet the 10.000
> > Gb-Mtr objective in addition to the 9.548 Gb-Mtr objective.
> >
> > A unified PMD set can support the block encoded LAN PHY and the scramble
> > encoded WAN PHY, allowing both to meet the 10.000 Gb-Mtr objective.
> > This will allow the PMD people to concentrate on the technologies of the
> > PMDs with the consideration of a signaling range to support both PHYs.
> > It will also simplify the marketing of 10GbE by reducing the confusion
> > about distances and fiber types.
> >
> > As was demonstrated in some of the previous presentations (SUPI and OIF
> > SERDES), it is possible to have unified PMDs without having a unified
> > PHY.  If the question had been asked, would it have made a difference to
> > separate the issues?  If they are separate issues, as a I believe they
> > are, then should the survey be redone with that segregation?  Would this
> > have put less pressure on group to have a unified PHY and changed the
> > scaling of the responses?
> >
> > Thank you,
> > Roy Bynum
> >
> >
> >