RE: Equalization and benefits of Parallel Optics.
These are interesting views which point to an inversion in the statements of
the two MMF objectives. For many, the 300m objective is not satisfactorily
addressed unless it works over "installed" fiber. (Technically, "installed"
fiber could be anything including new MMF, but is usually understood to mean
"worst-case" fiber, i.e. 160MHz-km.) Since the longest lengths of MMF are
the ones are most painful to replace, the desire to continue their use is
understandable. Shorter-length room connections are more often new
installations which don't need actual replacement.
The term "installed" appears in the 100m objective and has little relevance
to it. "Installed" does NOT appear in the 300m objective, but people want
it there anyway...
Regards,
Jack
-----Original Message-----
From: Bruce Tolley [mailto:btolley@xxxxxxxxx]
Sent: Thursday, July 27, 2000 5:25 PM
To: Booth, Bradley; stds-802-3-hssg@xxxxxxxx
Subject: RE: Equalization and benefits of Parallel Optics.
Paul and Brad:
I do not think the 300 meter objective was written with computer rooms in
mind. It was written with building and campus backbones in mind.
This was the context of the discussion within the distance ad hoc leading
up to the York meeting.
My recollection from the York meeting is that we started discussing an
objective for 300 meters on installed fiber and ended up with consensus
on objective that omitted the word "installed. "
At the time, it seemed to me to be a compromise between those who wanted to
support the installed base with 1300 WWDM and those who wanted to support
850 serial PMDs on new MM fiber. Both sets of voters were thinking in
terms of building and campus backbones. The distance value of 300 meters
itself has always been justified on the basis that it covers some
substantial percentage of the installed base of building and campus
backbones.
Yours
Bruce
At 02:35 PM 7/27/00 -0700, Booth, Bradley wrote:
>Paul,
>
>Thanks for pointing that out. I stand corrected. The parallel optics and
>parallel fiber could be applied to the 300m over MMF objective. Although
it
>does meet that objective, the previous emails were targeting parallel
>optics/fiber for the 100m application, and I should have probably qualified
>my statement with that.
>
>If it is only going to meet the 300m over MMF objective (and from Pat
>Gilliland's presentation, only on new high bandwidth MMF), then I have the
>same problem with this solution as I do with the 850nm Serial PMD solution.
>They may both be the lowest cost today, but they don't satisfy the 100m
over
>installed MMF objective. Considering we have two PMDs that are under
>consideration to meet both the 100m over installed MMF and 300m over MMF
>objectives, I believe it would be in the Task Force's best interest to
focus
>on those solutions. That is just my humble opinion.
>
>Cheers,
>Brad
>
>Brad Booth
>Intel LAN Access Division, Austin Design Center
>bradley.booth@xxxxxxxxx <mailto:bradley.booth@xxxxxxxxx>
>(512) 407-2135 office
>(512) 589-4438 cellular
>
>
> -----Original Message-----
> From: Paul Bottorff [mailto:pbottorf@xxxxxxxxxxxxxxxxxx]
> Sent: Thursday, July 27, 2000 3:34 PM
> To: Booth, Bradley; stds-802-3-hssg@xxxxxxxx
> Subject: RE: Equalization and benefits of Parallel
>Optics.
>
> Brad:
>
> I also understand our objectives in the same way. We don't
>have an
> objective for 100 m computer room connections. It seems to
>me the 300 m
> objective was written for computer rooms. The 300 m over
MMF
>could be
> applied to any fiber solution.
>
> Cheers,
>
> Paul
>
> At 12:55 PM 7/27/2000 -0700, Booth, Bradley wrote:
>
> >Ali,
> >
> > From my understanding of the objectives, the task force
>doesn't have a
> >distance objective of "100m data center applications."
We
>do have an
> >objective for 100m over installed MMF fiber. That 100m
>distance objective
> >was chosen because it reflects what is used in the data
>center applications.
> >If the task force satisfies the objective (which is a
>requirement for the
> >task force to do), then we provide a solution for the
>application. The
> >reverse is not true. If task force satisfies the
>application, then we don't
> >meet our objectives.
> >
> >Given that the task force has to satisfy objectives first
>and foremost, I
> >believe that it is key that the task force focus on those
>proposals that in
> >some manner satisfy an objective. As I see it, parallel
>optics and parallel
> >fiber do not satisfy any of our objectives; therefore,
the
>task force needs
> >to work on the ones that will satisfy our objectives.
> >
> >Cheers,
> >Brad
> >
> > -----Original Message-----
> > From: ghiasi
>[mailto:Ali.Ghiasi@xxxxxxxxxxx]
> > Sent: Thursday, July 27, 2000 2:17 PM
> > To: stds-802-3-hssg@xxxxxxxx;
>bradley.booth@xxxxxxxxx
> > Cc: Ali.Ghiasi@xxxxxxxxxxx
> > Subject: RE: Equalization and
>benefits of Parallel
> >Optics.
> >
> > Brad
> >
> > > From: "Booth, Bradley"
><bradley.booth@xxxxxxxxx>
> > > To: stds-802-3-hssg@xxxxxxxx
> > > Subject: RE: Equalization and benefits
>of Parallel Optics.
> > > Date: Wed, 26 Jul 2000 18:29:56 -0700
> > > MIME-Version: 1.0
> > > X-Resent-To: Multiple Recipients
> ><stds-802-3-hssg@xxxxxxxxxxxxxxxxxx>
> > > X-Listname: stds-802-3-hssg
> > > X-Info: [Un]Subscribe requests to
> >majordomo@xxxxxxxxxxxxxxxxxx
> > > X-Moderator-Address:
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> > >
> > >
> > > I have one question:
> > >
> > > Which of our distance objectives is
>satisfied with
> >parallel fiber and
> > > parallel optics?
> >
> > The 100 m data center applications.
> > >
> > > It has been my interpretation that
when
>we talked about
> >100m of installed
> > > base of MMF, that we were referring to
>the MMF fiber
> >currently available for
> > > use by 802.3z. Parallel optics does
not
>operate over this
> >installed base.
> >
> > You are correct parallel optics would
not
>operate over an
> >installed two fiber
> > plant. Parallel optics would loose if
you
>go in to an
> >installed fiber base.
> > What I suggested was 100m data center
>applications, where
> >the fiber are not
> > installed in the building wiring.
> >
> > Data center application are very
>significant as stated in
> >the last meeting
> > about half the total market. Solutions
>significantly lower
> >cost targeted
> > for sub 100 m is needed, otherwise there
>will several
> >proprietary solutions.
> > Parallel optics is the lowest cost,
almost
>mature after 3
> >years, lowest power,
> > and smallest foot print. Parallel
optics
>is ideal to get
> >bandwidth off the
> > edge of your board.
> >
> > Serial 850 or CWDM 850 can be another
>candidate for low cost
> >data center
> > applications by having cable advantage
>over parallell fiber.
> >But you need
> > to offset fiber advantage against power,
>size, cost,
> >testing, and maturity.
> >
> > >
> > > Or am I missing the point here?
> > >
> > > Cheers,
> > > Brad
> >
> > Thanks,
> >
> > Ali Ghiasi
> > Sun Microsystems
> >
> > >
> >
>
> Paul A. Bottorff, Director Switching Architecture
> Enterprise Solutions Technology Center
> Nortel Networks, Inc.
> 4401 Great America Parkway
> Santa Clara, CA 95052-8185
> Tel: 408 495 3365 Fax: 408 495 1299 ESN: 265 3365
> email: pbottorf@xxxxxxxxxxxxxxxxxx
>