RE: PMD discussion
Ed:
Today I need 3 solutions: very very short reach like 10 meters, 200 to 300
meters on installed 62.5 micron fiber, over 40 km but ideally 70 km on SM
fiber.
The first I can solve without a IEEE 802.3ae a standard. for the 2nd, only
1310 WDM works. For the third, 1550 nm serial is optimal. I am not sure I
am ready to choose a 4th but I would lean toward 1310 nm serial.
Bruce
At 10:54 PM 5/30/00 -0400, you wrote:
>Bruce,
>
>I thought we were on the same wavelength. I just needed to hear it for the
>umpteenth time. I agree the <100m links in central office or premise
>equipment room applications are being served by the many very short link
>proposals being defined at the OIF(parallel is one of them, so is serial
>1310 FP :).
>
>I concur that the 1310 WDM is optimized for the embedded MMF base and serial
>1310 DFB is optimized for SMF. So if you only want three, which should be
>the third. An 850 or 1550nm solution or both(4 PMDs)?
>
>Thanks,
>Ed
>
> > ----------
> > From: Bruce Tolley[SMTP:btolley@xxxxxxxxx]
> > Sent: Tuesday, May 30, 2000 5:58 PM
> > To: Cornejo, Edward (Edward); '802.3ae'; 'Jack Jewell'
> > Subject: RE: PMD discussion
> >
> >
> > Ed:
> >
> > As far as I am concerned comparing 850 nm WDM with 1310 nm WDM is like
> > comparing apples and oranges because they no not address the same customer
> >
> > segment.
> >
> > My customers want to run 10 GbE in the following spaces:
> >
> > 1) Very, very short reach for connections between switches in the same
> > room. For this application,parallel solutions seem to work fine
> >
> > 2) Building backbone on installed 62.5 micron MM fiber. For this
> > application, only one proposal works: 1310 nm WDM
> > There is no threshold of pain in regard to cost, since if I cannot sell to
> >
> > my installed base THIS BUSINESS IS DEAD ON ARRIVAL.
> >
> > The 850 nm WDM PMD could cost 1/10 that of the 1310 nm part but that does
> > me no good because the market is much smaller.
> >
> > Even if there were a substantial cost difference, because I expect cost to
> >
> > be a function of the experience curve, and the costs of the 1300 nm WDM to
> >
> > come down as volume ramps.
> >
> > And volume should ramp more quickly for a part that supports the
> > installed
> > base of 62..5 MM fiber. Remember, customers resist FORKLIFT UPGRADES. If
> >
> > you examine all the demonstrations to date of 10 gbE technology at trade
> > shows, they are all demonstrations of upgrades to technology and products
> > customers already have installed. This is no accident. We must support
> > the
> > installed base to have this market take off quickly.
> >
> > And by the way, if I am going to recommend new fiber for future proofing,
> > I
> > might as well recommend SM fiber.
> >
> > 3) Medium long reach ( 10 to 40 km). Several PMDs cover portions of this
> > spectrum. 1300 nm serial seems most optimal.
> >
> > 4) Very long reach (over 50 km). 1550 nm serial seems the most optimal.
> >
> > Thanks for listening
> >
> > Bruce
> >
> > Bruce Tolley
> > Enterprise Line of Business
> > Cisco Systems
> >
> > At 03:25 PM 5/30/00 -0400, Cornejo, Edward (Edward) wrote:
> >
> > >Jack, et al,
> > >
> > >I could almost live with the list you have below, however, I thought Mr.
> > >Tolley mentioned the importance of the embedded base(62.5um) up to 300m.
> > If
> > >this is the case, I would change the WDM from the 850 to 1310 window. The
> > >only issue is cost between the two WDM solutions and I am sure there is a
> > >difference, but by how much?
> > >
> > >Also, systems folks need to tell us what their threshold of pain is for
> > >delta differences in cost. Is it 10%, 15%, 20% or 25%(0% is not an
> > option,
> > >sorry). This could make our decision easier.
> > >
> > >Regards,
> > >Ed
> > >
> > >
> > >
> > > > ----------
> > > > From: Jack Jewell[SMTP:jljewell@xxxxxxxxxxxxx]
> > > > Sent: Tuesday, May 30, 2000 2:59 PM
> > > > To: '802.3ae'
> > > > Subject: RE: PMD discussion
> > > >
> > > >
> > > > Walt (and others who have responded in the interim),
> > > >
> > > > Although I am encouraged that the group will come to some agreement
> > > > without
> > > > delaying our schedule, there is still some way to go. Given the
> > breadth
> > > > of
> > > > the 5 objectives set forth, it seems almost certain that a 3-PMD set
> > will
> > > > leave at least one objective being greatly under-optimized. I would
> > hate
> > > > for that to be the highest volume product. Following the theme of
> > > > optimizing for each space presented Thursday by Steve Haddock (and
> > > > departing
> > > > from his presentation of only 3 spaces), I would see the following as
> > the
> > > > optimal solutions for each Objective. Given the concensus that the
> > 2km
> > > > and
> > > > 10km objectives are best served by a common PMD, we are really
> > discussing
> > > > 4
> > > > distinct Objectives. Most of the debate is focused on the
> > > > shorter-distance
> > > > objectives, so this note focuses on them. I recommend the 4-PMD set
> > > > below.
> > > >
> > > > SMF up to 40km - 1550nm Serial
> > > >
> > > > SMF up to 10km (incl 2km) - 1310nm Serial
> > > >
> > > > MMF up to 300m - 850nm Serial
> > > >
> > > > Installed MMF up to 100m - 850 CWDM
> > > >
> > > > Highest Volume Product Space
> > > > The highest-volume product space here is almost certainly the MMF up
> > to
> > > > 300m. This is due to most of the transceivers being put into new
> > products
> > > > with new fibers. An interesting comment was made last Thursday
> > regarding
> > > > 100Mb Ethernet in which 3 PMDs were spec'd in order to accommodate TX
> > > > grade
> > > > cable as well as the installed base of T2 and T4 cable. Subsequently
> > the
> > > > T2
> > > > and T4 were more or less abandoned and virtually the entire market
> > went
> > > > for
> > > > the TX-based PMD. [I did not participate in that process; this is my
> > > > interpretation of the comments made last Thursday. If this is
> > inaccurate,
> > > > I
> > > > apologize.]
> > > >
> > > > Cost "Survey"
> > > > There have been several comments today regarding costs of different
> > PMDs.
> > > > The cost comparisons which I (and Paul K) presented were NOT the
> > result of
> > > > an "unscientific survey." They are the average of estimates which
> > were
> > > > circulated on the reflector. No one was excluded from presenting
> > their
> > > > own
> > > > numbers. I believe a great deal of thought was put into each
> > estimate.
> > > > Are
> > > > the numbers accurate? Of course not. Are they all consistent enough
> > to
> > > > represent the general picture (which is how they were presented)?
> > > > Absolutely. They have been presented publicly and privately with no
> > > > voiced
> > > > disagreement.
> > > >
> > > > Relative Costs of Serial and WDM
> > > > It has been suggested and sometimes even stated outright that a WDM
> > > > solution
> > > > will be as low-cost or even lower-cost than a serial solution. This
> > is
> > > > unsupportable. I put this question to (and look for responses from)
> > > > vendors
> > > > who have manufactured and sold transceivers in any reasonable volume.
> > > > (These are the ones who know transceiver costs better than anyone.)
> > Does
> > > > your optical subassembly cost more than your ICs? In expectation of a
> > > > unanimous "Yes" to that question, comes the next question. In order
> > to
> > > > move
> > > > to higher performance levels while minimizing the cost increase should
> > > > you:
> > > > 1) increase the complexity of your optics; or 2) increase the
> > complexity
> > > > of
> > > > your ICs? This is why we aren't seriously discussing a WDM-only set
> > of
> > > > PMDs. WDM is a good way to get more data over a fiber than otherwise
> > > > possible - but it's used only when simpler approaches cannot be used.
> > As
> > > > for the ICs, there were a lot of IC vendors at the meeting having
> > > > aggressive
> > > > goals and impressive capabilities. Assuming a "market entry" for
> > 10GbE
> > > > products at the end of this year, it is reasonable to forecast that
> > the
> > > > cost
> > > > to produce a serial product will be less than its equivalent WDM
> > product
> > > > at
> > > > the time of market entry or within 6 months after that. I.e. for
> > > > essentially the entire product lifetime.
> > > >
> > > > The 4 PMDs recommended above are not biased in order to favor my
> > company's
> > > > choice of PMDs; rather my company's choice of PMDs is based on a hard
> > view
> > > > of the markets and technologies required to address them in an
> > economical
> > > > fashion.
> > > >
> > > > Jack
> > > >
> > > >
> > > >
> > > > -----Original Message-----
> > > > From: Walter Thirion [mailto:wthirion@xxxxxxxxxxxx]
> > > > Sent: Sunday, May 28, 2000 11:58 AM
> > > > To: '802.3ae'
> > > > Subject: PMD discussion
> > > >
> > > >
> > > >
> > > > First of all, thanks to everybody that presented PMD proposals at the
> > last
> > > > meeting. I've sent my presentation to David Law, so it should be
> > available
> > > > on the web site in the next couple of days.
> > > >
> > > > In listening to the discussion after my presentation and then going
> > around
> > > > and talking to people, it feels to me like we're starting to converge.
> > Not
> > > > there, yet, but making progress.
> > > >
> > > > The equipment manufacturers made it pretty clear they would like to
> > see no
> > > > more than 3 PMDs in the standard. The PMD vendors have some concern
> > that
> > > > using only 3 PMDs may sub-optimize certain objectives, however, they
> > could
> > > > support the 3 PMD position if it is made clear which 3 PMDs the
> > equipment
> > > > oems want.
> > > >
> > > > Based on an informal straw poll and anecdotal evidence, my opinion is
> > the
> > > > first choice would be the set:
> > > > ________________
> > > > 850 nm WWDM
> > > > 1310 nm WWDM
> > > > 1550 nm Serial
> > > > ________________
> > > >
> > > > If that set isn't feasible, then the 2nd most popular choice is:
> > > > ________________
> > > > 850 nm WWDM
> > > > 1310 nm Serial
> > > > 1550 nm Serial
> > > > ________________
> > > >
> > > > Thoughts, feedback?
> > > >
> > > > Walt
> > > > ___________________
> > > > Walter Thirion
> > > > Chair, IEEE 802.3ae PMD Sub-Task Force
> > > > 301 Congress Ave.
> > > > Suite 2050
> > > > Austin, Texas 78701
> > > > Voice: 512-236-6951
> > > > Fax: 512-236-6959
> > > > wthirion@xxxxxxxxxxxx
> > > > ___________________
> > > >
> >