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RE: [EFM] Active Architectures

And the installer isn't color blind...


At 03:45 PM 8/21/01 -0400, Francois D. Menard wrote:

>Not if the multimode has a different color/cladding than the single mode
>-----Original Message-----
>[] On Behalf Of Geoff
>Sent: August 21, 2001 2:01 PM
>To: Horne, David M
>Cc: 'Carlos Ribeiro';
>Subject: RE: [EFM] Active Architectures
>I believe that you are overlooking the chief merit of the single fibre
>or P2mP) solution.
>That is: The installer will have a much more difficult time getting it
>wrong if there is only one fiber.
>Having the cable-end appearance have a multi-mode and a single mode
>destroy this advantage and increase the average termination time to:
>          1) Guess which fiber
>          2) Terminate that fiber
>          3) Test the termination
>          4) Aw #$%%*!
>          5) Got to step 1
>     Divided by 2
>At 07:20 AM 8/21/01 -0700, Horne, David M wrote:
> >Hello Carlos, on your comment: "I see one immediate problem. I assume
> >that the 850 nm lasers are coupled to multimode fiber, and that the
> >downstream PON needs to use a singlemode fiber. If this is correct,
> >then every home would have to be served by two fibers of different
> >construction. I've heard news of fibers able to carry both single and
> >multimode signals but haven't seen any hard data on this."
> >
> >Yes, that is why I made the below comment in my original message:
> >"There are a couple options on the fiber between the node and the ONU
> >but I'll leave that discussion for later."
> >
> >I don't think I'd use the word "problem" to describe it since it is
> >quite solvable. It's more a question of which method is used. I would
> >advocate the use of microtubing or conduit between the node and each
> >ONU. That way, the fiber or fibers would only be installed (blown-in or
> >pulled) when a subscriber signs up for service. Likewise, the ONU would
> >only be installed at that time. It doesn't have to be done this way,
> >but to do otherwise would leave the network operator with stranded
> >assets in the field. In some cases these assets could sit idle for a
> >very long time. Another option is the customer could own both the fiber
> >and the ONU and have them installed by a third-party when they
> >subscribe to a service. The second strand is still quite a minimal cost
> >compared to the transmitter cost savings that the architecture
> >provides. In a neighborhood of 1/4 acre lot sizes, the average run for
> >a cluster of 16 homes would be about 170 meters or so.
> >
> >The extra fiber (if 2 are used) shouldn't be viewed as an additional
> >cost per-se. It is just a part of the architecture decision and the
> >OVERALL costs are what matter. It is easy to single out an
> >architectural difference and concentrate on what that costs, as an
> >argument against something, but in reality the big picture is what
> >matters. Big-picture-wise, this apparent extra cost disappears.
> >
> >If a single fiber were used, I believe there are methods such that it
> >could be either singlemode or multimode. Anyone who can provide cost
> >and performance details of such an arrangement please do. I find very
> >little published on this, except to imply feasibility. In any case I
> >tend to think this would be more expensive overall than 2 separate
> >fibers since mux and demux components are needed. It may be
> >straightforward off-the-shelf components but I think those cost more
> >than 170 meters of fiber.
> >
> >
> >
> >
> >-----Original Message-----
> >From: Carlos Ribeiro [mailto:cribeiro@xxxxxxxxxxxxxxxx]
> >Sent: Tuesday, August 21, 2001 4:16 AM
> >To: Frank Coluccio; david.m.horne@xxxxxxxxx
> >Cc: sganguly@xxxxxxxxx; ramu_raskan@xxxxxxxxxxxxx;
> >
> >Subject: Re: [EFM] Active Architectures
> >
> >
> >(in the context of David Horne's "half-PON" idea)
> >At 20:22 20/08/01 +0000, Frank Coluccio wrote:
> > >For extremely long runs, have you considered the tradeoffs of an
> > >inexpensive cwdm solution in lieu of multiple strands coming back
> > >from the ONUs?
> >
> >That was my first thought when reading David's proposal. In fact I
> >already discussed similar views not only with David, but with lots of
> >people in this list. That's the main reasoning to develop a wavelength
> >alocation plan that allows for the future use of C/DWDM. Gerry
> >Pesavento is going to discuss this issue.
> >
> >As far as Mr. Horne proposal is concerned, I see one immediate problem.
> >I assume that the 850 nm lasers are coupled to multimode fiber, and
> >that the downstream PON needs to use a singlemode fiber. If this is
> >correct, then every home would have to be served by two fibers of
> >different construction. I've heard news of fibers able to carry both
> >single and multimode signals but haven't seen any hard data on this.
> >
> >
> >Carlos Ribeiro
> >CTBC Telecom