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Re: AW: 1550nm Serial PMD Question


The 1500 nm 10Ge is intended for dark fiber, not for WDM networks. There 
are no IEEE objectives to make the 1500 nm spec operate with WDM or even to 
make it operate over optical amplification. The 1500 nm interface allows 10 
Ge to operate over a 40 Km dark fiber which has a 10Ge PHY at both ends. If 
this signal were extended further it would require a switch or repeater 
before the next fiber segment. The 10 Ge specification can support a WDM 
optical network by using a 1300 nm interface into the edge of the WDM 
network where a transponder at the edge of the WDM network transforms the 
signal into the "ITU Grid" and reforms the clock to the requirements of the 
WDM network.



At 09:37 AM 5/4/2001 +0200, Rahn, Juergen (Juergen) wrote:

>The spec is indeed not in line to the "ITU Grid". However  it should be
>noted that beside this small pree condition of supporting particular
>wavelength there are a lot further specs required that are not at all in the
>Ethernet document. This means this interface in the current spec is not
>suited for direct WDM also. For WDM you would in this case require a real
>SDH/SONET interface. In this respect it should also be noted that one reason
>(beside the optical parameters that do not support effective transmission)
>is the way the jitter is specified as this prevents the cascadability of 3 R
>regens which are needed in WDM networks of larger dimensions.
>Regards Juergen Rahn
> > ----------
> > Von:  Marshall Eisenberg[]
> > Gesendet:     Mittwoch, 2. Mai 2001 16:39
> > An:
> > Betreff:      1550nm Serial PMD Question
> >
> >
> > All,
> > A while back there were rumors that the 1550nm Serial PMD would be ITU
> > Grid
> > Spec compliant, making it DWDM 'ready'   I've downloaded draft D3.0 and
> > cannot find any references or further notations.  Can anyone shed any
> > light
> > on this or point out the relevant section in the draft?
> >
> > Regards,
> >
> > Marshall Eisenberg
> > Director of product marketing
> > Foundry Networks Inc.
> > 2100 Gold Street
> > P.O. Box 649100
> > San Jose, CA 95164-9100
> > (408) 586-1754 direct
> > (408) 586-1900 fax
> > (408) 398-0014 mobile
> >
> >

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