Re: Going the distance
- To: "Cornejo, Edward (Edward)" <ecornejo@xxxxxxxxxx>, HSSG <stds-802-3-hssg@xxxxxxxx>
- Subject: Re: Going the distance
- From: Rich Taborek <rtaborek@xxxxxxxxxxxxxxxx>
- Date: Thu, 01 Jul 1999 11:39:33 -0700
- Organization: Transcendata, Inc.
- References: <00D8FC294498D211915D00805F19988423F5DD@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
- Reply-To: rtaborek@xxxxxxxxxxxxxxxx
- Sender: owner-stds-802-3-hssg@xxxxxxxxxxxxxxxxxx
Ed,
I have no general objections to an additional 10 km and 40 km objectives for SMF
for the the reasons indicated below. However, I'll reiterate Howard Frazier's
advice with respect to setting distance objectives per ISO/IEC 11801:
"If we adopt this objective (2-3 km for campus cabling), we can make progress on
the rest of the work we need to do as a study group. As was demonstrated in
802.3z, we will need to review the objectives periodically, and revise them if
there is consensus to do so."
From a Marketing perspective:
- I have heard about significant demand for 10-15 km 10 GbE SMF links from many
sources quoting fairly large volumes. I'll leave it to our surveys to quantify
"large volumes"
- I'm not so sure about the 40 km number. It sound a bit short for the MAN/WAN
environment and I expect the volumes to be significantly less relative to 10-15
km links. We're also playing with fire here since this is the domain of existing
MAN/WAN equipment and I agree with experts like Roy Bynum and Paul Bottorff
about how different the operational requirements here are than our familiar LAN
environment. This objective scares me as to the supplementary requirements
associated with the distance and how much work it will be to satisfy those
requirements in our 10 GbE standard. Think 'delayed standard' here.
- SMF is not a widely deployed LAN "installed base" fiber. I believe that this
eliminates any installed base arguments regarding these objectives.
From a Technical perspective:
- I have absolutely no problem supporting either the 10 or 40 km objectives from
a multilevel signaling perspective since this signaling is essentially
independent of the PMD choice and can easily accommodate single optical laser
required to achieve these distances, whether it be 1310 or 1550 nm. The proposed
PAM5 signaling rate is only 5 GBaud to achieve 10 Gbps, thereby halving the
dispersion effects at long distances.
- For the 40 km objective more expensive (not that much more) optical
components including optical isolators can be used here to provide a higher RIN,
offsetting the effects of SNR loss due to multilevel signaling.
In summary, I'm not so concerned about a 10 km SMF objective for the 10 GbE PAR
and would support it. I would have a more difficult time supporting the 40 km
solution due to all the "supplementary" issues.
I would have a far more difficult time supporting any MMF objective which
excludes ANY proposed PHY solution by requiring the support of specific
low-bandwidth fibers at distances which only a small subset of proposed PHY
solutions can support. Such an ill formed objective would certainly
unnecessarily increase the cost of high volume 10 GbE products and would be a
huge blow to the 10 GbE standards effort at this point in our process.
--
"Cornejo, Edward (Edward)" wrote:
> I have no problem including 2km, 10km, and 40km. So I would support your
> comments.
>
> Ed-Lucent
>
> > ----------
> > From: Bruce_Tolley@xxxxxxxx[SMTP:Bruce_Tolley@xxxxxxxx]
> > Sent: Thursday, July 01, 1999 1:40 PM
> > To: Cornejo, Edward (Edward)
> > Cc: stds-802-3-hssg@xxxxxxxx
> > Subject: RE: Going the distance
> >
> >
> >
> > Ed:
> >
> > I would like to see the numbers go like this for SM fiber: 2, 10, and 40
> > (if
> > possible).
> >
> > Bruce
> >
> >
> >
> >
> > "Cornejo, Edward (Edward)" <ecornejo@xxxxxxxxxx> on 07/01/99 10:36:19 AM
> >
> > Sent by: "Cornejo, Edward (Edward)" <ecornejo@xxxxxxxxxx>
> >
> >
> > To: stds-802-3-hssg@xxxxxxxx
> > cc: (Bruce Tolley/HQ/3Com)
> > Subject: RE: Going the distance
> >
> >
> >
> >
> >
> > Brian,
> >
> > It seems that HP and Lucent have a general consensus on having an
> > objective
> > that lists two distance requirements for single mode fiber.
> >
> > How does the rest of the committee feel about a 2km and 10km single mode
> > fiber objectives? Is this something that has a possibility of >75%
> > approval.
> >
> > Ed-Lucent
> >
> >
> >
> > > ----------
> > > From:
> > >
> > BRIAN_LEMOFF@xxxxxxxxxxxxxxxxxxxxxxxxxx[SMTP:BRIAN_LEMOFF@HP-PaloAlto-om16
> > > .om.hp.com]
> > > Sent: Thursday, July 01, 1999 12:33 PM
> > > To: Cornejo, Edward (Edward); stds-802-3-hssg@xxxxxxxx
> > > Subject: RE: Going the distance
> > >
> > >
> > > Ed,
> > >
> > > I don't agree that the laser is always the "big ticket item in a
> > > transceiver". This may be true in long-haul telecom (and it may be
> > > true for 10GbE serial), but in both 1000-SX and 1000-LX
> > transceivers,
> > >
> > > the laser (i.e. VCSEL or FP) accounts for a small fraction of the
> > > overall transceiver cost. It is by no means obvious that a serial
> > 10G
> > >
> > > FP transceiver, will cost less than a 4x2.5G WWDM transceiver.
> > > Regardless of this, I don't think it will hurt the process to have
> > a
> > > 2km objective in addition to a 10km objective.
> > >
> > > -Brian Lemoff
> > > HP Labs
> > >
> > >
> > > ______________________________ Reply Separator
> > > _________________________________
> > > Subject: RE: Going the distance
> > > Author: Non-HP-ecornejo (ecornejo@xxxxxxxxxx) at HP-PaloAlto,mimegw2
> > > Date: 7/1/99 7:33 AM
> > >
> > >
> > > I believe 2km over SMF will cover a majority of Campus LAN applications,
> > > and
> > > therefore a good place to start. I base the 2km distance on FDDI cabling
> > > structure, GE survey presented by Chris D., and ISO's 2-3km spec.
> > >
> > > The serial proposal is two fold, one for shorter reach(2km), and one for
> > > intermediate reach(15km). The 2km approach uses an uncooled unisolated
> > > Fabry-Perot laser; this should be considerably less cost than 4 uncooled
> > > unisolated DFBs(i.e. WWDM approach). I know there are other factors here
> > > like packaging, and electronics, but I believe most folks would agree
> > that
> > > the laser is the biggest ticket item in a transceiver. If the minimum
> > > distance is >2km, you will be excluding a potentially lower cost
> > solution.
> > > Unnecessarily IMHO because it covers a majority of your applications.
> > >
> > > For the same reasons I want 2km, I would not want to exclude anyone at
> > the
> > > longer distances. Therefore, I would support 2km, and 10km as the two
> > > distances for SMF. Also, in my view the two distance proposals would be
> > > the
> > > same footprint and electrical interface to the PCS or MAC, so it is not
> > a
> > > major hassle having seperate laser spec's for the PMD.
> > >
> > > Going further distances beyond 10km, or 15km is never a problem; it is
> > > just
> > > how much customers are willing to pay.
> > >
> > > I concur with my colleague from HP that we should meet customer demands,
> > > but
> > > also consider technology capabilities and costs. Lets not be too
> > exclusive
> > > at this early juncture. It is always easier to increase our distances
> > than
> > > to throttle them back in case we run into unforseen problems with MMF or
> > > SMF
> > > at 10G.
> > >
> > > Ed-Lucent
> > > > ----------
> > > > From:
> > > >
> > >
> > BRIAN_LEMOFF@xxxxxxxxxxxxxxxxxxxxxxxxxx[SMTP:BRIAN_LEMOFF@HP-PaloAlto-om16
> > > > .om.hp.com]
> > > > Sent: Wednesday, June 30, 1999 7:36 PM
> > > > To: pbottorf@xxxxxxxxxxxxxxxxxx
> > > > Cc: Bruce_Tolley@xxxxxxxx; hfrazier@xxxxxxxxx;
> > > > rtaborek@xxxxxxxxxxxxxxxx; stds-802-3-hssg@xxxxxxxx
> > > > Subject: Re: Going the distance
> > > >
> > > >
> > > > Paul:
> > > >
> > > > I believe that the WWDM approach that we have presented, when
> > used
> > > > with uncooled, unisolated, reduced spec (on SMSR, linearity, RIN)
> > > > DFBs
> > > > will cost equal or less than the serial 10G FP laser approach
> > that
> > > > Lucent has proposed for 2km, and significantly less than the
> > > isolated
> > > >
> > > > DFB approach that they have proposed for 15km. This would
> > support
> > > > ~300m on 62.5 micron fiber, and ~10km on SMF. To push this
> > > approach
> > > > to 15km may involve tightening the SMSR or RIN spec which will
> > > > significantly increase the cost (since much of the low-cost
> > nature
> > > of
> > > >
> > > > the approach depends upon using low-cost DFBs).
> > > >
> > > > I realize that there is an ongoing debate about relative cost,
> > but
> > > it
> > > >
> > > > would be a shame to set the objectives at 2km and 15km, when
> > there
> > > is
> > > >
> > > > a potentially very low-cost solution that can go 10km. I have no
> > > > problem with a 2km and 10km objective, since I believe we can
> > > satisfy
> > > >
> > > > both with a single cost-competitive solution.
> > > >
> > > > I realize that Rich Taborek and others have criticized PMD
> > > suppliers
> > > > (such as HP and Lucent) on this reflector for suggesting
> > > objectives,
> > > > based on what each of our solutions can handle, but I don't think
> > > we
> > > > can afford to ignore it either. I don't deny that I favor 300m
> > on
> > > > installed base MMF and 10km on SMF in large part because that is
> > > what
> > > >
> > > > our WWDM module can support. I have no problem backing off on
> > > these
> > > > (say to 200m and 5km) if it allows alternative PMDs to be
> > > considered.
> > > >
> > > > Lucent wants 2km (not 3km) to be an objective so that their
> > serial
> > > FP
> > > >
> > > > laser module is not excluded. I'd like 10km (and not 15km) for
> > the
> > >
> > > > same reason (although I believe we're still competitive at 2km).
> > > >
> > > > Distance objectives should reflect what the customers need, but
> > > > should
> > > > be influenced by what the available technologies can achieve.
> > > >
> > > > -Brian Lemoff
> > > > HP Labs
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > ______________________________ Reply Separator
> > > > _________________________________
> > > > Subject: Re: Going the distance
> > > > Author: Non-HP-pbottorf (pbottorf@xxxxxxxxxxxxxxxxxx) at
> > > > HP-PaloAlto,mimegw2
> > > > Date: 6/30/99 3:24 PM
> > > >
> > > >
> > > >
> > > > Bruce:
> > > >
> > > > I support your outlook. We already have 5-10 km with gigabit.
> > Supporting
> > > > these distances is necessary to support the installed base. Since the
> > > > technology cut-off point is around 20 km and since a standard MAN
> > > distance
> > > > is 15 km I'd prefer a slightly more aggressive objective of 15 km.
> > This
> > > > would still give reasonable design margin. I also believe lower cost
> > > > technology exits below 2.5 km motivating a 2 km specification. We
> > could
> > > > either specify a single 15 km objective which covers all the
> > > applications
> > > > with a higher component cost or 2 km and 15 km each with a different
> > > price
> > > > point.
> > > >
> > > > I would like to see further extension into the MAN. GigE is selling
> > day
> > > > with reaches over 50 km. The next standard distance is 40 km. I've
> > heard
> > > > this distance was chosen to match the spacing of microwave towers.
> > With
> > > > the
> > > > 40 km distance I believe we would have all that is necessary to build
> > > > Metro
> > > > networks.
> > > >
> > > > The three standard distances on SMF would be 2, 15, and 40 km. Each of
> > > > these ranges I believe falls into a different technology with a
> > > different
> > > > price point. If anyone has a technology which can do all three at the
> > 2
> > > km
> > > > price then all the better.
> > > >
> > > > Paul
> > > >
> > > > At 09:13 AM 6/30/99 -0700, Bruce_Tolley@xxxxxxxx wrote:
> > > > >
> > > > >
> > > > >
> > > > >The point has been made before that today customers are already going
> > 5
> > > > to
> > > > 10 Km
> > > > >with 1000BASE-LX. There should be no debate that it is a market
> > > > requirement to
> > > > >go 5 to 10 km with 10 GbE.
> > > > >
> > > > >While I am willing to consider accepting a conservative 2 to 3 km
> > goal
> > > > as
> > > > the
> > > > >official goal of the project, we need to acknowledge that this is a
> > > > >conservative goal and, as we get on with the work of the project , we
> > > > should
> > > > >investigate whether we can stretch this goal..
> > > > >
> > > > >Bruce Tolley
> > > > >3Com Corporation
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >Rich Taborek <rtaborek@xxxxxxxxxxxxxxxx> on 06/29/99 05:01:32 PM
> > > > >
> > > > >Please respond to rtaborek@xxxxxxxxxxxxxxxx
> > > > >
> > > > >Sent by: Rich Taborek <rtaborek@xxxxxxxxxxxxxxxx>
> > > > >
> > > > >
> > > > >To: Howard Frazier <hfrazier@xxxxxxxxx>, HSSG
> > > > <stds-802-3-hssg@xxxxxxxx>
> > > > >cc: (Bruce Tolley/HQ/3Com)
> > > > >Subject: Re: Going the distance
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >Howard,
> > > > >
> > > > >I will gladly accept your suggestion of removing the portion of the
> > > > >motion in parenthesis as a friendly amendment post-haste given your
> > > > >support of this motion as a seconder.
> > > > >
> > > > >- Rich
> > > > >
> > > > >Howard Frazier wrote:
> > > > >
> > > > >> The more I think about it, the more I like the idea of adopting the
> > > > >> 802.3z link distance objectives for 10 Gig. We should remember that
> > > > >> we are still in the study group phase, trying to scope out a
> > project.
> > > > >> We can always adjust the objectives later.
> > > > >>
> > > > >> Let me therefore state my support for Rich's proposed motion:
> > > > >>
> > > > >> > "Support the premises cabling plant distances as specified in
> > > > >> > ISO/IEC 11801"
> > > > >> >
> > > > >> > The distances supported in ISO/IEC 11801 are:
> > > > >> >
> > > > >> > 100 m for horizontal cabling (applicable to copper, MMF, SMF)
> > > > >> >
> > > > >> > 550 m for vertical cabling: (applicable to SMF and possibly MMF)
> > > > >> >
> > > > >> > 2-3 km for campus cabling: (applicable to SMF)
> > > > >>
> > > > >> Rich, I would encourage you to drop the parenthesis.
> > > > >>
> > > > >> If we adopt this objective, we can make progress on the rest of the
> > > > >> work we need to do as a study group. As was demonstrated in
> > 802.3z,
> > > > >> we will need to review the objectives periodically, and revise them
> > > > >> if there is consensus to do so.
> > > > >>
> > > > >> Howard Frazier
> > > > >> Cisco Sytems, Inc.
> > > > >
> > > > >-------------------------------------------------------------
> > > > >Richard Taborek Sr. Tel: 650 210 8800 x101 or 408 370 9233
> > > > >Principal Architect Fax: 650 940 1898 or 408 374 3645
> > > > >Transcendata, Inc. Email: rtaborek@xxxxxxxxxxxxxxxx
> > > > >1029 Corporation Way http://www.transcendata.com
> > > > >Palo Alto, CA 94303-4305 Alt email: rtaborek@xxxxxxxxxxxxx
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > Paul A. Bottorff, Director Switching Architecture
> > > > Bay Architecture Laboratory
> > > > 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
> > > >
> > >
> >
> >
> >
> >
> >
--
Best Regards,
Rich
-------------------------------------------------------------
Richard Taborek Sr. Tel: 650 210 8800 x101 or 408 370 9233
Principal Architect Fax: 650 940 1898 or 408 374 3645
Transcendata, Inc. Email: rtaborek@xxxxxxxxxxxxxxxx
1029 Corporation Way http://www.transcendata.com
Palo Alto, CA 94303-4305 Alt email: rtaborek@xxxxxxxxxxxxx