RE: Why 10xGbE may be a bigger market than 1xGbE - a customer's perspective

["Bill St. Arnaud" <bill.st.arnaud@canarie.ca>]

DSF - dispersion shifted fiber has been around since the 70s. Generally
dispersion is high, but linear in the 1550 region.  Can be compensated with
dispersion correcting fiber.
ZDSF - zero dispersion shifted fiber was deployed in the 80s. The lowest
point in the dispersion curve was moved to the 1550 wavelength.  The
dispersion slope therefore formed a "V" at the 1550 wavelength.  This is
ideal for single wavelength TDM transmission.  MCI has installed 1000s of
miles of this type of fiber.  But almost useless for DWDM
NZDSF - non zero dispersion shifted fiber is currently what is deployed.
The low level, liner (but not the zero point) portion of the dispersion line
has been shifted into the 1530-1570 region of the fiber.  Ideal for long
haul DWDM systems

Bill

-------------------------------------------
Bill St Arnaud
Director Network Projects
CANARIE
bill.st.arnaud@canarie.ca
http://tweetie.canarie.ca/~bstarn

 

 



> -----Original Message-----
> From: owner-stds-802-3-hssg@majordomo.ieee.org
> [mailto:owner-stds-802-3-hssg@majordomo.ieee.org]On Behalf Of Scott
> Lowrey
> Sent: Thursday, May 06, 1999 11:11 AM
> To: bill.st.arnaud@canarie.ca
> Cc: 'HSSG_10GbE'
> Subject: RE: Why 10xGbE may be a bigger market than 1xGbE - a customer's
> perspective
>
>
> I'm not familiar with the acronym ZDSF...I'd assume that it's Zero
> Dispersion (Something) Fiber?  Would you mind defining it for me?
>
> Scott Lowrey
>
> ******************************************
>
> Scott Lowrey
>
> Network Elements, Inc.
> 9782 SW Nimbus Ave.
> Beaverton, Oregon 97008
>
> 503-644-2385
> Fax  503-644-1507
>
>
> -----Original Message-----
> From: owner-stds-802-3-hssg@majordomo.ieee.org
> [mailto:owner-stds-802-3-hssg@majordomo.ieee.org]On Behalf Of Bill St.
> Arnaud
> Sent: Thursday, May 06, 1999 5:35 AM
> To: David W Dolfi
> Cc: stds-802-3-hssg@ieee.org; dolfi@hpl.hp.com
> Subject: RE: Why 10xGbE may be a bigger market than 1xGbE - a customer's
> perspective
>
>
> David:
>
> I am only speculating that WWDM may not work on long distance with ZDSF.
> Because ZDSF fiber has steep dispersion slopes away from the zero point
> wavelengths that are located the furthest away from the zero point would
> suffer significantly more dispersion than those closer to the zero point.
>
> The dispersion is non linear on ZDSF fiber so the dispersion generally
> cannot be compensated with dispersion compensating devices.  Most
> ZDSF fiber
> is 1550, and so in the 1310 range the dispersion would be linear.
>
> On 10 Km distances this may not impact WWDM particularly if you use narrow
> spacing.  I was thinking more in terms of 20-80 km distances and CWDM
> spacing.
>
> The multi-level analog signaling is conceptually appealing.  But you are
> correct that it may not be practical in the field.  Multi-level signaling
> requires very linear lasers and detectors.  Does anybody know who laser
> linearity degrades with age and temperature??  How susceptible is
> the system
> to optical noise, etc etc
>
> Bill
>
>
> -------------------------------------------
> Bill St Arnaud
> Director Network Projects
> CANARIE
> bill.st.arnaud@canarie.ca
> http/tweetie.canarie.ca/~bstarn
>
>  
>
>  
>
>
>
> > -----Original Message-----
> > From: David W Dolfi [mailto:dolfi@saiph.hpl.hp.com]
> > Sent: Wednesday, May 05, 1999 9:29 PM
> > To: bill.st.arnaud@canarie.ca
> > Cc: stds-802-3-hssg@ieee.org; dolfi@hpl.hp.com
> > Subject: FW: Why 10xGbE may be a bigger market than 1xGbE - a customer's
> > perspective
> >
> >
> >
> > To: Bill ST Arnaud/CANARIE
> >
> > From: David Dolfi/Hewlett-Packard
> >
> > Subject: DWDM in "gopher" fiber
> >
> > Date: 5/5/99
> >
> > Your message to the GbE high speed study group (below) was forwarded
> > to me by one of my engineers.  In it you make the point that wide WDM
> > (WWDM) might not work on "gopher bait" fiber.  As an advocate of WWDM
> > for 10 Gb Ethernet, I would like to understand why this is the case.
> > I would think that fiber which is damaged or overspliced would work
> > better at the lower baud rate (3.125 GBd) of 4 channel WWDM than at
> > the 4X higher baud rate (12.5 GBd) of serial 10 Gb Ethernet.
> >
> > Please remember when responding  that the 4 channel WWDM we are
> > advocating
> > for 10 Gb Ethernet has the following properties:
> >
> > 1. The targeted link lengths are 10 km or less, so no EDFA's are
> > required.
> > 2. The 4 wavelengths we are using are in the 1300 nm region of the
> > spectrum (NOT 1550) and have channel spacings of 15-20 nm.
> >
> > Finally, I would think that fiber which is overspliced and/or
> > damaged would have a high loss, and I'm puzzled why a multi-level
> > coding scheme (which typically requires a high S/N ratio) would be
> > suitable for such fiber while WWDM would not.
> >
> > Am I missing the point here?  Please respond!
> >
> > Dave Dolfi
> > email: dolfi@hpl.hp.com
> >
> >
> > ------------- Begin Forwarded Message -------------
> >
> > From lbuckman@exch.hpl.hp.com Wed May  5 16:01:23 PDT 1999
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> > From: "Buckman, Lisa" <lbuckman@exch.hpl.hp.com>
> > To: "DOLFI, DAVE (HP-PaloAlto,unix3)" <dolfi@hpl.hp.com>,
> >         "LEMOFF, BRIAN (HP-PaloAlto,unix3)" <lemoff@hpl.hp.com>
> > Subject: FW: Why 10xGbE may be a bigger market than 1xGbE - a
> customer's p
> > 	erspective
> > Date: Wed, 5 May 1999 16:02:43 -0700
> > MIME-Version: 1.0
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> >
> > Dave and Brian,
> > Here is a message against WWDM...
> >
> > Lisa
> >
> >
> > -----Original Message-----
> > From: Bill St. Arnaud [mailto:bill.st.arnaud@canarie.ca]
> > Sent: Wednesday, May 05, 1999 2:44 PM
> > To: David_Law@3com.com; stds-802-3-hssg@ieee.org
> > Subject: Why 10xGbE may be a bigger market than 1xGbE - a customer's
> > perspective
> >
> >
> > All:
> >
> > I have been watching the 802.3 high speed study group developments with
> > interest.  This is a technology development we have been pushing
> > the vendors
> > for almost 2 years now.  We are aware of a number of
> proprietary solutions
> > that have been promised to us later this year.  So I hope the
> study group
> > moves quickly to develop a common standard.
> >
> > We are deploying an optical Internet across Canada
> www.canet3.net.  We are
> > currently using POS, but we have identified a lot of
> deficiencies with POS
> > and we believe that "simplex, auto-negotiation 10xGbE" might be a better
> > solution for medium/long range WANs up to 1000 km.  Here are
> the reasons:
> >
> > 1.  There is a lot of "gopher bait" fiber in the ground that
> the carriers
> > can't use for traditional SONET networks. Gopher bait fiber is
> > usually fiber
> > that has been damaged, or has too many splices and will not
> > support OC-48 or
> > OC-192 clock rates. As well, a lot of carriers in the 80s deployed ZDSF
> > fiber that was optimized for TDM traffic and will not support
> > WDM. So these
> > carriers are leaving this stuff in the ground and are now
> deploying NZDSF
> > fiber that can support DWDM
> >
> > Ad hoc estimates we have heard is that about 30% of the installed
> > fiber base
> > is gopher bait.
> >
> > We believe that auto -negotiation 10xGbE would be the perfect
> protocol for
> > such a fiber, even if we use inefficient 8b/10b coding.
> >
> > 2. With auto-negotiation we could use the gopher bait fiber with long
> > repeater spacing, perhaps starting off with clock rates at less
> > than 1xGbE.
> > As demand for bandwidth increases we could install intermediary
> > transceivers
> > (and/or EDFA or PDFA) to support a faster clock rate.  It allows
> > us to have
> > small upfront capital cost and incrementally grow the network
> bandwidth as
> > demand warrants rather than installing an expensive up front
> OC-192 system
> > and highly conditioned fiber.
> >
> > Auto-negotiation might also compensate for PMD changes as it varies
> > throughout the day.
> >
> > 3. A practical as possible we believe that 10xGbE should be
> made a simplex
> > protocol.  The Internet, itself is fundamentally a
> > unicast/simplex network.
> > In the Internet today there is significant asymmetric traffic
> > loads between
> > the Tx/Rx paths -in some case the asymmetric variance can be
> > 16:1.  As such
> > we are deploying links where they may be more Tx paths than Rx
> > paths.  Since
> > there is no guarantee that there will an Rx for every Tx, as much as
> > possible auto-negotiation protocols, laser safety signaling
> should be done
> > at the IP layer.  Maybe the PHY should be IP addressable and
> > managed at the
> > IP layer?
> >
> > 4. We would hope that the study group would also look at some of the
> > proposed SDL protocols as increasingly many optical links will
> run on data
> > and bit rate transparent networks. The overhead associated with
> > CRC, etc is
> > not necessary any more.
> >
> > 5. We believe that either a serial TDM, or multi-level signal
> > protocol would
> > be the best as WWDM might not work very well on gopher bait fiber
> >
> > Looking forward to see the results of your deliberations.  We are in the
> > process of setting up a 10xGbe 50 km and 500km test facility
> for those who
> > might be interested in experimenting with some of the 10xGbE concepts
> >
> > Also, we have some background papers for those who are interested in our
> > program on optical Internet technologies
> >
> >
> > Bill
> >
> > -------------------------------------------
> > Bill St Arnaud
> > Director Network Projects
> > CANARIE
> > bill.st.arnaud@canarie.ca
> > http://tweetie.canarie.ca/~bstarn
> >
> >  
> >
> >  
> >
> >
> >
> > > -----Original Message-----
> > > From: owner-stds-802-3-hssg@majordomo.ieee.org
> > > [mailto:owner-stds-802-3-hssg@majordomo.ieee.org]On Behalf Of
> > > David_Law@3com.com
> > > Sent: Wednesday, May 05, 1999 11:28 AM
> > > To: stds-802-3-hssg@ieee.org
> > > Subject: Higher Speed Study Group e-mail reflector archive
> > >
> > >
> > >
> > >
> > > All,
> > >
> > > After discussions with the IEEE it has been agreed that the
> > > reflector archive no
> > > longer needs to be in a password protected area of the web site.
> > > Due to this the
> > > archive has been moved to a new URL:-
> > >
> > > http://grouper.ieee.org/groups/802/3/10G_study/email/thrd1.html
> > >
> > > Please update any boookmarks you may have of the old location.
> > >
> > > Thanks,
> > >    David Law
> > >
> > > |=========================================|
> > > | David Law                               |
> > > | Vice-Chair IEEE 802.3                   |
> > > | 3Com                                    |
> > > | 3Com Centre,                            |
> > > | Boundary Way,                           |
> > > | Hemel Hempstead,                        |
> > > | Hertfordshire, HP2 7YU,                 |
> > > | United Kingdom                          |
> > > | Phone: +44 1442 438060                  |
> > > | Fax:   +44 1442 438333                  |
> > > | E-Mail: David_Law@3com.com              |
> > > |=========================================|
> > >
> > >
> > >
> > >
> >
> > ------------- End Forwarded Message -------------
> >
>
>