Re: (SSIG) Taking the winning route
Hi Mike,
My comment on Serial solutions was with respect to the installed based of MMF,
which is "FDDI grade" 62.5 um MMF as I understand it. The bandwidth of this
fiber @ 850 nm is typically no more than 200 MHz*km. At 10.3125 GBaud, this
translates to roughly:
200 MHz*km
--------------- = ~39 meters (the fastest signaling rate is 1/2 the Baud.
This number is inflated since it does
10.3125 GBaud/2 not consider laser rise/fall time which
corresponds to a higher effective signaling BW)
Serial 850 nm solutions can easily achieve 100 m, but require new "enhanced"
MMF. This fiber does not correspond to the installed fiber base.
Assuming that by VCSEL, you mean "serial VCSEL at 850nm" for purposes of cost
comparison, I estimate the cost differences between the various PHYs as (very
roughly):
1 GbE LX PHY current cost = 1
10 GbE Serial VCSEL @ 850 nm in (2002) = 2-3
10 GbE WWDM @ 1300 nm in (2002) = 3-4
10 GbE Serial 1300 nm in (2002) = 2-4
Best Regards,
Rich
--
Mike Bennett wrote:
>
> Hi Rich,
>
> I have a few questions for you: What distance would you say the 850nm serial VCSEL
> solution would reach? If 100m is not possible for serial VCSEL at 850nm, please
> explain why not. What would you estimate the relative cost difference between the VCSEL
> and 1300nm WWDM PHYs will be, say normalized to current LX PHYs?
>
> Respectfully,
>
> Mike Bennett
> Lawrence Berkely Lab
>
> Rich Taborek wrote:
>
> > Martin,
> >
> > I apologize, I should have included a bit more detail with my last response. I'm
> > currently way backed-up with reflector traffic for the week and now see that my
> > response left out some details.
> >
> > WWDM 1300nm is the only strongly supported PHY proposal which addresses the
> > intalled base of MMF.
> >
> > No Serial solutions, including the 850nm serial VCSEL solution, address the
> > installed base of MMF at reasonable distance. I peg this disatance at 100m as
> > does the corresponding distance/cable plant objective.
> >
> > The point of my previous note was that the 850nm serial VCSEL solution over
> > enhanced MMF meets only one distance/cable plant objective, whereas WWDM 1300nm
> > meets the same one plus three others, rendering it as a much more flexible and
> > encompasing solution. In simply counting objective checkmarks, it's 4-to-1 in
> > favor of WWDM.
> >
> > We all agreed to HSSG objectives. It's time to select PHY's according to these
> > objectives. I agree with Vipul's picks.
> >
> > --
> >
> > Best Regards,
> > Rich
> >
> >
> > Martin Nuss wrote:
> > >
> > > Of all the MM-fiber PMD proposals, only the 850nm serial VCSEL solution over the
> > > new high-performance fibers has so far been shown to work under stressed systems
> > > conditions, with Bit Error Rate measurements and careful analysis of the systems
> > > impairments to support that, and working with VCSELs from many vendors. The
> > > suggestions below are highly puzzling to me...
> > >
> > > Martin
> > >
> > > Rich Taborek wrote:
> > > >
> > > > Vipul, Rob,
> > > >
> > > > It should be pointed out that a Serial 850nm solution only partially meets one
> > > > HSSG distance/cable plant objective: 300m on MMF. However, this MMF must be the
> > > > new, enhanced MMF. The Serial 850nmsolution addresses no SMF objectives
> > > >
> > > > WWDM meets all HSSG MMF objectives as well as SMF objectives to 10km.
> > > >
> > > > I agree with Vipul's choice of 3 PMDs as the best possible PMD set to address
> > > > HSSG HSSG distance/cable plant objectives.
> > > > Best Regards,
> > > > Rich
> > > >
> > > > --
> > > >
> > > > Vipul Bhatt wrote:
> > > > >
> > > > > Rob,
> > > > >
> > > > > Rob Marsland wrote:
> > > > > >
> > > > > > Finally, I hate to be annoying, but this is the SERIAL sig. Since when is
> > > > > > WWDM a serial solution?
> > > > > >
> > > > >
> > > > > There is nothing annoying about your question. I should answer. I believe it
> > > > > is in our (the Serial SIG's) best interest to rise above our Serial focus and
> > > > > recognize that an "all Serial" set of solutions that meets all the distance
> > > > > objectives is not something our customers are willing to sign up for. By
> > > > > proposing a set of three solutions - two of which are Serial - I am proposing
> > > > > a set that has the highest chance of being accepted by our customers and the
> > > > > majority of 802.3ae members. I understand you disagree, and I respect your
> > > > > opinion.
> > > > >
> > > > > Vipul
-------------------------------------------------------
Richard Taborek Sr. Phone: 408-845-6102
Chief Technology Officer Cell: 408-832-3957
nSerial Corporation Fax: 408-845-6114
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