Re: Re: RE: [EFM] EFM Active Architectures
I think we're in sync wrt periodic upgrades in ONUs and CPEs,
etc. As you suggest, it's in some ways similar to a LAN upgrade.
"The basic PON architecture (SM fiber and splitter) has,
for all intents and purposes, unlimitedbandwidth."
As long as you've included the qualifier, "SM", we're in agreement
there, too too. And that was my point of posting. It had
to do with the possible inclusion of MMF.
> If we take seriously the estimates of the reletive
> cost of deployment of a fiberplant vs. the active
> electronics (90%/10%, or so), I think that it makes a
> lot of sense to give long and careful thought to
> insuring that the basic fiberplant topology doesn't
> become obsolete. On the other hand, periodic upgrades
> to the end opto-electronic packages would seem to me
> to be acceptable over the working lifetime of the
> fibre. This isn't unlike the periodic upgrades of
> NIC's in LAN's.
> To burden, say, an ONU with a receiver capable of some
> day accepting a 10GBE datastream, would be the sort of
> overkill that will make any system prohibitively
> expensive. The basic PON arcitecture (SM fiber and
> splitter) has, for all intents and purposes, unlimited
> This view would suggest that making the ONU an easily
> replacable module (like a set-top box) might be a
> better choice than hanging it on the side of a house.
> Additionally, this solves the problem of power (plug
> it in a wall socket) and will save quite a bit of
> money by putting the opto-electronics in an
> environmentally benign location. Don't underestimate
> the difficulty of getting these devices to function
> from -40 to +85 degrees.
> --- Frank Coluccio <fcoluccio@xxxxxxxxxxxxxxxxx>
> > [Second attempt at getting this message out... ]
> > Frank Effenberger,
> > Yes, as with Dave's half-PON concept which I also
> > like very
> > much, the TDM and slicing options are also of
> > interest and
> > certainly deserving of further investigation.
> > The thing that occurs to me, at least in the two
> > optical
> > tracks of EFM (p2p and pt-mpt), is this:
> > How do either of these proposed designs, or _any_ of
> > the
> > others, for that matter, lend themselves to
> > extensibility
> > to higher speeds down the road? Stated another way,
> > should an
> > approach that "locks in" an upper bound on
> > throughput be of
> > concern? As in, being able to deliver the next two
> > powers
> > of 10 beyond 100Mb/s (since 100 is often cited as
> > the target
> > delivery rate at this time), at least, without a
> > major forklift
> > when they arrive. What happens to be friendly at 100
> > Mb/s
> > between the OLT and/or the field "thingie" and the
> > ONU at
> > this time may not be as friendly at 10Gb/s or
> > higher.
> > Or, is this even something that should concern EFM
> > at this time?
> > FAC
> > >
> > > All,
> > > We have considered this topology to some degree
> > ourselves.
> > > The variant we considered is to use TDM in the
> > downstream,
> > > and WDM in the upstream. The advantages of doing
> > this are
> > > that you avoid the TDMA protocol issues, and you
> > save N lasers.
> > > over doing it point-to-point. You also reduce
> > your spectrum
> > > requirement by a factor of 2 (half as many
> > wavelengths), and
> > > this can be key if you are using coarse WDM.
> > Since cost is
> > > key, CWDM would be a good direction. Spectral
> > slicing is
> > > also an interesting option.
> > > Versus a TDMA PON, you must add N receivers at the
> > CO; however,
> > > an array of receivers is *much* more tractable
> > than an array
> > > of WDM lasers.
> > > Lastly, the use of WDM in the upstream retains the
> > all passive
> > > outside plant advantage of PON. No field
> > electronics.
> > >
> > > Any interest?
> > > Frank Effenberger.
> > >
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