Re: Unified PMD vs. Unified PHY
A LAN only PHY that is at 10Gbps transfer rate is exactly what I am talking
about. The proposed "UniPHY" is ~3% less than the original proposal for a
WAN compatible PHY which, as you pointed out, is less than the original LAN
PHY to start with.
As far as a unified PHY is concerned, no one has said that the WAN
compatible PHY could not be used in a privately owned fiber systems, like
the LAN PHY. The WAN compatible PHY just has ~5% less MAC transfer rate.
As far as I know, there has never been a presentation that would only work
in the WAN, ie. a WAN only PHY. This understanding makes the WAN compatible
PHY functional as a reduced rate LAN PHY. In other words, the unified PHY
that Jonathan Thatcher is wanting is already the WAN compatible PHY.
I think that the preferences that came out of the survey that Jonathan
indicates that the majority of the group would prefer the WAN compatible PHY
because it will support both the LAN and WAN implimentations at only ~5%
overhead cost. From what I have been able to determine, the actual
implementation costs seem to be about the same. The second alternative is
seperate LAN only and WAN compatible PHYs.
----- Original Message -----
From: Rich Taborek <rtaborek@xxxxxxxxxxx>
To: HSSG <stds-802-3-hssg@xxxxxxxx>
Sent: Friday, March 24, 2000 11:09 AM
Subject: Re: Unified PMD vs. Unified PHY
> I believe that you have overhead sources twisted a bit.
> All proposals for the LAN PHY support a MAC data transfer rate of 10 Gbps.
> are you referring to when you say ~10% slower? The only thing that's
> the MAC's accepted 10 Gbps data rate is legacy SONET OC-192c and it's
> Best Regards,
> Roy Bynum wrote:
> > Andreas,
> > The real question is, do we need a LAN PHY that is ~10% slower than the
> > 10.000 Gigbit transfer rate that was so important in June, July,
> > and November of 1999? Did all of that support for 10.000 Gigabit
> > disappear? It makes me very suspicious. The additional ~3% loss to the
> > compatable PHY is a seperate issue.
> > Thank you,
> > Roy Bynum
> > ----- Original Message -----
> > From: Andreas Bechtolsheim <avb@xxxxxxxxx>
> > To: <stds-802-3-hssg@xxxxxxxx>; <wthirion@xxxxxxxxxxxx>
> > Sent: Thursday, March 23, 2000 10:29 AM
> > Subject: RE: Unified PMD vs. Unified PHY
> > >
> > > Roy,
> > >
> > > the question is do we need to create two separate PHY standards
> > > because of a 3% difference in transmission efficiency.
> > >
> > > If you look at the results of the Albuquerque straw poll,
> > > the majority of 802.3ae appears to answer this question with "no".
> > >
> > > Andy
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