Re: PMD discussion
[Date: 06/05/2000 From Seto]
Roy,
Thanks for your response.
In the previous history of Ethernet, 100BASE-FX benefited from using the
same PCS as 100BASE-TX. Most of 100BASE-TX PHY LSIs out in the market
serve as 100BASE-FX PHY. Also, many 1000BASE-T PHY LSIs, which does not
use 8B10B PCS, benefited from using same TBI i/f as 1000BASE-X. For this
purpose, many 1000BASE-T PHYs have 10B8B capability internally.
I believe WAN PHY will also benefit from sharing the same PCS component
and interface with LAN PHY, and I think this is one of compelling reasons
that WAN PHY groups agreed to adopt UniPHY approach despite the 3%
inefficiency UniPHY PCS would introduce to WAN PHY.
Seto
> Seto,
>
> What you are saying is that it is only so that the WAN compatible PHY
could be standardized to use the same XAUI as the LAN only,
> Serial ONLY, PHY that the WIS was introduced, when the WAN compatible
PHY implementers will probably not even use XAUI? How
> convoluted is that? I thought, and perhaps quite a few other people
thought that the whole reason for the "UniPHY" was to have only
> ONE PHY, not two LAN only PHYs and one WAN compatible PHY with the WAN
compatible PHY being force to share the same PCS coding of
> only one of the LAN only PHYs, to the detriment of the WAN compatible
PHY. If we are to have a "UniPHY" then it needs to be a
> single PCS for all PHY/PMD combinations, otherwise there is not "UniPHY".
>
> Thank you,
> Roy Bynum
>
>
> ----- Original Message -----
> From: "Seto, Koichiro" <seto@xxxxxxxxxxxxxxxxxxxx>
> To: <ka@xxxxxxxxxx>; <rabynum@xxxxxxxxxxxxxx>
> Cc: <rtaborek@xxxxxxxxxxx>; <stds-802-3-hssg@xxxxxxxx>
> Sent: Monday, June 05, 2000 3:59 PM
> Subject: Re: PMD discussion
>
>
> > [Date: 06/05/2000 From Seto]
> >
> > Roy and Kamran,
> >
> > Right or wrong, it has been my understanding the WWDM uses 8b10bx4ch
coding.
> > Serial LAN PHY uses 64B66B coding. WWDM is a different PHY.
> >
> > It is also my understanding that WWDM LAN PHY, Serial LAN PHY and
Serial WAN
> > PHY are UniPHYs in a way it can share the same XGMII and the optional
XAUI
> > interface. Before WIS is introduced, LAN PHY and WAN PHY could not
share
> > XAUI or XGMII because WAN PHY needed frame length information to
encode a
> > frame.
> > To all, please correct me if I'm wrong.
> >
> > Sincerely,
> > Seto
> >
> > > Roy,
> > >
> > > I have the same concern.
> > > CWDM uses a different code (8b/10b) than serial (64b/66b), the LAN-
PHY and
> > > WAN-PHY
> > > have different denominations representing different 10GE PHYs (as
per May
> > > meeting)
> > > resulting in 10 different PHYs LAN and WAN together!!
> > >
> > > What is UniPHY exactly?? What is it unifying anyway?
> > >
> > > Why are we forcing on the WAN-PHY a code that is bandwidth
inefficient and
> > > incompatible
> > > with the SONET world?
> > >
> > > Kamran
> > >
> > >
> > >
> > >
> > > Roy Bynum wrote:
> > > >
> > > > Rich,
> > > >
> > > > Now I am confused. It was my understanding that the LAN only PHY
would
> > be using 64b/66b, just like what is being forced on the WAN
> > > > compatible PHY. If so, then it was my understanding that the
parallel/
> > CWDM PMD would also be 64b/66b.
> > > >
> > > > Thank you,
> > > > Roy Bynum
> > > >
> > > > ----- Original Message -----
> > > > From: "Rich Taborek" <rtaborek@xxxxxxxxxxxxx>
> > > > To: "HSSG" <stds-802-3-hssg@xxxxxxxx>
> > > > Sent: Saturday, June 03, 2000 2:35 AM
> > > > Subject: Re: PMD discussion
> > > >
> > > > >
> > > > > Ed,
> > > > >
> > > > > Done! I completely agree to drop this tangent and focus on PMD
issues.
> > > > >
> > > > > Best Regards,
> > > > > Rich
> > > > >
> > > > > --
> > > > >
> > > > > NetWorthTK@xxxxxxx wrote:
> > > > > >
> > > > > > Rich:
> > > > > >
> > > > > > I believe you misunderstood my mail to conclude your comments
too
> > quickly.
> > > > > >
> > > > > > I never mentioned that I like the 12.5 Gbps 8B/10B coding to
be
> > replaced by
> > > > > > 10.3125 Gbps 64b/66b.
> > > > > >
> > > > > > We are discussing serial vs parallel issues.
> > > > > >
> > > > > > We are too much involved in resolving PMD issues right now,
and I
> > believe no
> > > > > > one is interested in bring the coding scheme back to reflector
at
> > this moment.
> > > > > >
> > > > > > Please do not intiate this one. let us focuse on PMD issues.
> > > > > >
> > > > > > Regards,
> > > > > >
> > > > > > Ed Chang
> > > > >
> > > > > -------------------------------------------------------
> > > > > Richard Taborek Sr. Phone: 408-845-6102
> > > > > Chief Technology Officer Cell: 408-832-3957
> > > > > nSerial Corporation Fax: 408-845-6114
> > > > > 2500-5 Augustine Dr. mailto:rtaborek@xxxxxxxxxxx
> > > > > Santa Clara, CA 95054 http://www.nSerial.com
> > >
>
>