Re: Muni fiber: L1 or L2?

[Scott Helms <khelms () zcorum com>]

Owen,

I'm trimming this for my own sanity if I snip out something important
please let me know.


> So long as you recognize that it's on a pair-by-pair basis end-to-end and
> not expecting any mixing/sharing/etc. by the L1 infrastructure provider,
> yes.

OK good, now we're speaking on the same topic :)


> > > Is it more expensive to home-run every home than to put splitters in the
> > > neighborhood? Yes. Is it enough more expensive that the tradeoffs cannot be
> > > overcome? I remain unconvinced.
> >
> >
> > This completely depends on the area and the goals of the network.  In
> > most cases for muni networks back hauling everything is more expensive.
> >
> >
> > I agree it's more expensive. The question is whether it's enough more
> > expensive to make it infeasible. You still haven't come anywhere near
> > addressing that question.
>
> I've said repeatedly that this a network by network analysis.  I've never
> said its infeasible, but that it is more expensive both initially and long
> term in MOST installs.  That by itself is generally enough to invalidate
> the design since in almost all cases there's no benefit to home running all
> the connections.  It doesn't make the connection faster nor do ISPs (as a
> group) care about a layer 1 versus layer 2 hand off.
>
>
> That's where we disagree. The benefit is that:
>
> 1. It doesn't lock the entire area into a single current technology.
Neither does a ring architecture.


> 2. It allows for individual subscribers (probably mostly businesses, but
> I have had a few occasions
> where this would have been useful as an individual) to get dark XC to
> other locations.
Neither does a ring architecture, you do have fewer long runs, but in any
build you're going to end up with spare pairs to use for this and in my
experience the number of businesses who want this in given area are very
small.  I can't think of a network where this is more than 1% of the
business connections.


> 3. Subscribers who want individualized services from different vendors
> have a choice.

Subscribers don't care if the hand off is at layer 1 or layer 2 so this is
moot as well.


> 4. Providers have to compete on a leveled playing field and there is thus
> incentive to innovate
> even if the innovation moves away from PON.

Again, this is a completely moot point.  There is nothing in a ring or hub
& spoke architecture that makes open access more difficult EXCEPT if you
want to share lots of L1 connections.


> > > I'm not sure why you think it would be hard to delineate the
> > > responsibilities… You've got a fiber path maintained by the municipality
> > > with active equipment maintained by the ISP at each end. If the light
> > > coming out of the equipment at one end doesn't come out of the fiber at the
> > > other end, you have a problem in the municipality's domain. If the light
> > > makes it through in tact, you have a problem in the ISP's domain.
> > >
> > > There is equipment available that can test that fairly easily.
> >
> > OK, this one made my wife get scared I laughed so hard.  You clearly have
> > never tried to do this or had to work with different operators in the same
> > physical network.  Please, go talk to someone whose worked in the field of
> > a FTTx network and describe this scenario to them.  Its clear you don't
> > want to hear it from me via email so please go do some research.
> >
> >
> >
> > I've talked to a few people doing exactly that. Yes, you need different
> > test sets depending on which L2 gear is involved, but, in virtually ever
> > case, there is a piece of test gear that can be used to test a loop
> > independent of the configuration of the L2 gear in question.
>
> Yes, there is a meter for all the different kinds of technologies that you
> might want to support.  For example a DOCSIS 3.0 DSAM from JDSU will run
> you around $8000.00  A PON meter with long range lasers (more than 10
> miles) from JDSU or Trilithic will cost you nearly $10,000.  Exactly how
> many of those kinds of meters do you want to have to buy?  How many of your
> staff are you going to train on them (they do require training and
> knowledge to  use)?
>
>
> For my proposed methods of build-out, no need for the long range lasers.
> As I said, everything should be within 8km of the MMR.
>
> As I suggested, the simpler approach is to require the complaining L2
> provider to cooperate in the diagnostic process and provide access to the
> applicable meters if necessary. The standard offered absent assistance from
> the L2 provider is OTDR success.

Medium range lasers (anything that's running on single mode fiber) versus
long range don't drive the cost.  OTDR is not and cannot test for any phase
modulated system and that includes every form of PON, Active Ethernet, and
RFoG.  You _might_ be able to use one to test RS-232 over fiber depending
on the vendor.  This is where you're really not getting it.  As the owner
of the physical medium you WILL be the blame of every problem until you
prove differently.  Every end user install that goes poorly, every
time there is a connection drop, and every time some end user of $L1
partner calls them complaining the city will get the blame.



> > For providers getting L1 service, it wouldn't be too hard to make this
> > testing /  providing necessary test equipment part of their contract.
> >
> > The long and short of it is lots of people have tried to L1 sharing and
> > > its not economical and nothing I've seen here or elsewhere changes that.
> > >  The thing you have to remember is that muni networks have to be cost
> > > effective and that's not just the capital costs.  The operational cost in
> > > the long term is much greater than the cost of initial gear and fiber
> > > install.
> > >
> > > We can agree to disagree. A muni network needs to be able to recover its
> > > costs. The costs of building out and maintaining home-run
> > > fiber are not necessarily that much greater than the costs of building
> > > out and maintaining fiber at the neighborhood. One option, for
> > > example, would be to have neighborhood B-Boxes where the fiber can
> > > either be fed into provider-specific splitters (same economy
> > > as existing PON deployments) or cross-connected to fiber on the F1 cable
> > > going back to the MMR (home-run).
> > We can agree all we want, that doesn't change history.  Handing out
> > connections at layer 1 is both more expensive and less efficient.  Its also
> > extremely wasteful (which is why its more expensive) since your lowest unit
> > you can sell is a fiber strand whether the end customer wants a 3 mbps
> > connection or a gig its the same to the city.  I'm not saying you shouldn't
> > sell dark fiber, I'm saying that in 99% of the cities you can't build a
> > business model around doing just that unless your city doesn't want to
> > break even on the build and maintenance.
> >
> >
> > If it's $700 per home passed to build out home-run fibers (which seems to
> > be a reasonable approximation from earlier discussions), then there's no
> > reason you can't sell $40/month service over that where the L1 component is
> > a $10/month ($7 for capital recovery, $3 for operations and support)
> > pricing component.
>
> Nope, no reason at all if you don't care about covering your costs.
>
>
> I just explained where the expected costs get covered, so you're going to
> have to explain that statement.

No, you listed some more than optimistic numbers and passed that off as
evidence.  If you seriously think that the fiber connection is only worth
$10 per month then you're off by ~100%.


However, the point is that building the infrastructure in that manner
> > doesn't cost much more than building out traditional PON infrastructure (if
> > you're doing it from greenfield) and it can support either technology.
>
> Sure it does, even in greenfield and whats more it costs more over the
> long term UNLESS you know where every home and business will be located 10
> years from now.
>
>
> More yes, much more, I'm not so convinced.
You think the fiber connectivity is only worth $10 too....



> Owen


-- 
Scott Helms
Vice President of Technology
ZCorum
(678) 507-5000
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http://twitter.com/kscotthelms
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