RE: Equalization and benefits of Parallel Optics.
Sharam
> From: "Hakimi, Sharam (Sharam)" <hakimi@lucent.com>
> To: stds-802-3-hssg@ieee.org, "'Daljeet_Mundae@mitel.com'"
<Daljeet_Mundae@mitel.com>
> Subject: RE: Equalization and benefits of Parallel Optics.
> Date: Tue, 25 Jul 2000 21:04:49 -0400
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>
> Although parallel fiber is technically an easier solution, the major reason
> for support of 850nm has been to consider the installed base, and cost. If
> users have to pull new fiber, IMHO, parallel fiber would not be on top of
> the list and most of installed base is single fiber.
I did not suggest to pull any new fiber. Limit the shortwave variant
including parallel optics to the data center with 100 m radius.
Thanks,
Ali Ghiasi
Sun Microsytems
>
> Sharam Hakimi
> Lucent Technologies
>
> > ----------
> > From: Daljeet_Mundae@mitel.com[SMTP:Daljeet_Mundae@mitel.com]
> > Sent: Tuesday, July 25, 2000 6:02 PM
> > To: stds-802-3-hssg@ieee.org
> > Subject: RE: Equalization and benefits of Parallel Optics.
> >
> >
> >
> >
> > From: Daljeet Mundae@MITEL on 07/25/2000 06:02 PM
> > I quite agree with Ali. The parallel fibre solution is by far the most
> > cost
> > effective. For under 100M fibre lengths, both the cost of electronics and
> > the
> > optical module will be significantly lower when compared to serial
> > solutions
> > with no need for equalisation etc. The technology is here today and
> > easily
> > deployable.
> >
> > I am a little bit surprised that this option has not been explored more
> > rigorously - it makes a lot of sense for use in data centre and computer
> > room
> > installations.
> >
> > Daljeet Mundae
> > Mitel Semiconductor
> >
> >
> >
> >
> >
> > ghiasi <Ali.Ghiasi@Eng.sun.com> on 07/25/2000 12:30:17 PM
> >
> > Please respond to ghiasi <Ali.Ghiasi@Eng.sun.com>
> >
> > To: stds-802-3-hssg@ieee.org, wthirion@jatotech.com,
> > SwansonSE@corning.com
> > cc: Ali.Ghiasi@Eng.sun.com (bcc: Daljeet Mundae/Kan/Mitel)
> >
> > Subject: RE: Equalization
> >
> >
> >
> >
> > Hi Steve
> >
> > Steve Swanson wrote:
> > >
> > >
> > > Walt,
> > >
> > > The right ones to include are:
> > > 850 Serial
> > > 850 CWDM
> > > 1310 Serial
> > > 1310 CWDM
> > > 1550 Serial
> >
> > I am not sure Steve what criteria you are using to determine the right
> > ones!
> > Specially when you have left the lowest cost parallel optics out.
> >
> > I certainly can see if you want to support 300m at least on existing
> > fiber for the backbone the choices would be:
> >
> > 1300CWDM
> > 1310 Serial
> > 1550 Serial
> >
> > In addition the standard should consider lower cost variants to support
> > data center with maximum distance of 100m using standard fibers. A user
> > can always implement high bandwidth fiber if he wishes. Below you will
> > find suitable link choices for data centers:
> >
> > Serial 850 - difficult to reach 100m on standard fiber
> > 850 CWDM - Too early to judge
> > Parallel Optics - Lowest xcvr cost but long cables are expensive
> >
> > Thanks,
> >
> > Ali Ghiasi
> > Sun Microsystems
> >
> >
> > >
> > > The standard could move forward very efficiently - no debate over
> > objectives,
> > no debate over band-aids, no debate over how many, etc. My recommendation
> > to the
> > committee is to support these PMDs in the standard. Individual companies
> > and
> > customers can then decide whether to support all of them, none of them, or
> > some
> > number in between. The standard sets expectations in the marketplace and
> > encumbers noone. All of these PMDs have what I call "a critical level of
> > support" on both sides - customers AND vendors. In this case, it is better
> > at
> > this point in time to include rather than exclude.
> > >
> > > Best regards,
> > >
> > > Steve
> > >
> > > > ----------
> > > > From: Walter Thirion[SMTP:wthirion@jatotech.com]
> > > > Sent: Saturday, July 22, 2000 12:35 AM
> > > > To: stds-802-3-hssg@ieee.org
> > > > Subject: RE: Equalization
> > > >
> > > >
> > > > I would really like for us to get away from the 3 PMD vs 5 PMD
> > discussion
> > > > and determine which PMDs are the right ones to include in the
> > standard,
> > > > whether it's 2, 3, 4, 5 or (hopefully not) "more than 5".
> > > >
> > > > Walt
> > > >
> > > >
> > > > -----Original Message-----
> > > > From: NetWorthTK@aol.com [mailto:NetWorthTK@aol.com]
> > > > Sent: Friday, July 21, 2000 10:00 PM
> > > > To: vipul.bhatt@finisar.com; stds-802-3-hssg@ieee.org
> > > > Subject: Re: Equalization
> > > >
> > > >
> > > >
> > > > Vipul:
> > > >
> > > > It is a good summary. They are all true.
> > > >
> > > > However, we know all these facts for quite a while, and they are not
> > new to
> > > > us.
> > > > They are not simple problems to be resolved overnight. It will take
> > > > systematic approach and time to solve. I do not expect a miracle in
> > > > September to come out all answers -- rush, rush does not produce
> > miracle.
> > > >
> > > > Be practical, solid and smart to approach any problem.
> > > >
> > > > What I do not understand is why some people have to limit to 3 PMD
> > only.
> > > > There is no justified reason at all to insist 3-PMDs; as a result, the
> > 3-PMD
> > > >
> > > > is forcing us to produce a miracle. GIVE US A BREAK !! A successful
> > > > project
> > > > is always completed by practical approaches, but not by a miracle.
> > > >
> > > > We can vote 5 PMDs in, then we can concentrate next whole year to
> > resolve
> > > > all
> > > > those issues -- this is practical, and doable.
> > > >
> > > >
> > > > Regards,
> > > >
> > > > Ed Chang
> > > > NetWorth Technologies, Inc
> > > >
> > > >
> > > > Dear colleagues,
> > > >
> > > > Okay, so where are we? Let me review what I think I have heard so
> > > > far.
> > > >
> > > > Yes, the idea of 10G Serial on installed MMF is interesting, but
> > > > there are a couple of holes in the proposal, including bad timing.
> > > > Here is the summary, followed by holes.
> > > >
> > > > 850 nm Serial solution:
> > > > -----------------------
> > > > - Will benefit from TIA FO 2.2 Encircled Flux and Restricted Mode
> > > > Launch work.
> > > > - Offset Launch jumper not required.
> > > > - Start with 385 MHz-Km bandwidth assumption on installed MMF.
> > > > - Add 6 dB equalization to support 100 meters operation, additional
> > > > 9.54 dB to support 300 meters. Equalization has to be adaptive, in
> > > > the sense that impulse response will be different for each link. It
> > > > must overcome severe DMD in some cases. With Encircled Flux launch,
> > > > for a given link, the impulse response will not vary significantly
> > > > with time, so it can be assumed as time-invariant or very slowly
> > > > varying in time.
> > > > - Potentially, end up with a total of 3 PMDs that meet all 5
> > > > Objectives.
> > > >
> > > > 1310 nm Serial solution:
> > > > -----------------------
> > > > - Will benefit from EMB work done with 802.3z.
> > > > - Offset Launch jumper is required.
> > > > - Start with 500 MHz-Km bandwidth assumption on installed MMF.
> > > > - Add 4 dB equalization to support 100 meters operation, additional
> > > > 9.54 dB to support 300 meters. Equalization has to be adaptive in
> > > > the sense that impulse response will be different for each link. It
> > > > must overcome severe DMD in some cases. With offset launch, for a
> > > > given link, the impulse response will not vary significantly with
> > > > time, so it can be assumed as time-invariant or very slowly varying>
> > > > in time.
> > > > - Potentially, end up with a total of 2 PMDs that meet all 5
> > > > Objectives.
> > > >
> > > > List of holes:
> > > > -------------
> > > >
> > > > 1. It hasn't been established that Encircled Flux over a randomly
> > > > selected fiber from installed base will ensure 385 MHz-Km bandwidth
> > > > (850 nm) with a high degree of statistical confidence. Gair's
> > > > suggestion of tagging an RML-compliance condition is one possible
> > > > solution. We need to know if that suggestion will be acceptable to
> > > > 802.3ae end users and system integrators.
> > > >
> > > > 2. It hasn't been established that 10G equalization is feasible. By
> > > > feasible, I mean something like - a demonstrable solution before the
> > > > Working Group Ballot, capable of overcoming severe DMD, consuming
> > > > less than 3 watts, with a cost comparable to that of other
> > > > components, backed by technical presentations in September that
> > > > instill a high degree of confidence in the 802.3ae members.
> > > >
> > > > 3. Perhaps it is too late. There is a high likelihood that at the
> > > > September Interim, motions to adopt other PMDs that meet Objectives
> > > > 1 and 2 will pass.
> > > >
> > > > Hole 1 can be bypassed by adopting a 1310 nm Serial solution. Hole 2
> > > > can't be plugged until we have heard presentations from DSP experts
> > > > in September. Hole 3 is the most regrettable. I don't know how to
> > > > plug it. Jonathan, Walt, do you have any comments or suggestions?
> > > >
> > > > Thanks,
> > > > Vipul >>
> > > >
> >
> >
> >
> >
> >
> >
> >