Muni fiber: L1 or L2?

Tue Feb 5 00:48:42 UTC 2013

On Mon, Feb 4, 2013 at 6:29 PM, Masataka Ohta <
mohta at necom830.hpcl.titech.ac.jp> wrote:

> Scott Helms wrote:
>
> >> Unbundled copper costs about $10/M or so, which means SS fiber
> >> can't be more expensive.
>
> > I'm not sure what you're trying to describe here, the cost of fiber from
> an
> > ongoing standpoint isn't strongly correlated to the architecture.
>  Upgrades
> > to the fiber and adding service to new areas is a different animal.
>
> They are not soo different, as long as you try to recover initial
> cost not so quickly, which is why copper costs about $10/M or so.
>

I know several dozen companies that do this kind of construction and they
don't agree.

>
> >> it is stated that "Trenching consists of 70-80% of the total cost
> >> for infrastructure build".
>
> > Trenching != cabling and the total initial CAPEX is less than 25% of the
> > total cost over 10 years.
>
> My statement of "cable laying" includes trenching, sorry if it is
> not clear.
>
> And, you can see the slide contain "POP Active Equipment Cost",
> which you thought "most of the cost is in lighting the fiber",
> is already included.
>

Google is making their own access gear.  Their economy is very very
different from all of us here.

>
> > No, their existing equipment was Adtran, Calix, Occam, Alcatel, Zhone,
> AFC,
> > and a host of others but not SS copper or MDF.  By MDF I assume your'e
> > talking about main distribution frame which has nothing to do with the
> > discussion here.
>
> If you throw away optical MDF, there is no point to discuss
> L1 unbundling.
>

OK, historically the main distribution frame was where all of the copper
pairs came into a central office note that a phone company often had
several central offices to cover their territory in the time before there
were remotes (Digital Loop Carriers).  Today even when you home run all of
your fiber connections you bring it to a central patch panel(s) which
really doesn't look like a main distribution frame.  From a logical
standpoint that central set of patch panels is similar to a MDF but I
personally don't think about them the same way because a MDF is constructed
very differently.  (Google wire wraping telco tool)

>
> >> Surely, transition from copper to fiber is not trivial, but it
> >> helps a lot that fiber cables are thinner than copper cables.
>
> > Really, so you think that the thickness of the cable has an impact on how
> > much it should cost?  So, tell you what I'll exchange some nice thick
> > 10 gauge copper wire for 4 gauge platinum, since its much thinner that
> > ought to be a good trade for you, right?  ;)
>
> My point is that a conduit capable of storing additional 10 guage
> copper can, instead, store 10 guage fiber.
>
> Or, if you assume a conduit without any extra space, upgrading to
> PON is also impossible.
>

OK, twisted pair cabling isn't run in conduit.  Its not pulled the way that
fiber is.  Twisted pair plant is in a wiring bundle with a certain number
of pairs in that bundle.  You cannot remove the twisted pair in whole or
part and then run fiber through that cabling.  You can of course use the
same trench IF you have buried cable and there is room.  If you have aerial
plant (common in rural telco deployments, less common in muni networks) you
can also string your fiber on the same poles that you either own or have
attachment rights to but the thickness of the cable doesn't change your
costs any.

>
>                                                 Masataka Ohta
>
>

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