Re: (SSIG) Taking the winning route
Rich,
I should have read more carefully. Somehow I got the idea you were talking about High
Bandwidth MMF. The relative cost estimate is very informative. Thanks,
Mike
Rich Taborek wrote:
> 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
>
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