Re: Re: RE: [EFM] EFM Active Architectures
Thanks, Jay.
I think we're in sync wrt periodic upgrades in ONUs and CPEs,
etc. Like you say, it's no different at that level than
LAN/NIC upgrades.
As for:
"The basic PON architecture (SM fiber and splitter) has,
for all intents and purposes, unlimitedbandwidth."
As long as you've included the qualifier, "SM", I agree with
you on that point, too. And that was my point of focus. It had
to do with the possible inclusion of MMF, which I do not think
would be a good idea, unless the economics of its inclusion
was so dramatically in its favor as to make it unavoidable.
But I'd prefer to see mmf avoided altogether, if possible.
FAC
> Frank,
>
> 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
> bandwidth.
>
> 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.
>
> Jay
>
>
> --- Frank Coluccio <fcoluccio@xxxxxxxxxxxxxxxxx>
> wrote:
> >
> > [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.
> > >
> >
> >
>
>
> __________________________________________________
> Do You Yahoo!?
> Make international calls for as low as $.04/minute with Yahoo! Messenger
> http://phonecard.yahoo.com/
>