Muni network ownership and the Fourth

Sun Feb 3 13:00:02 UTC 2013

Leo Bicknell <bicknell at ufp.org> writes:

> In a message written on Sat, Feb 02, 2013 at 08:55:34PM -0500, Jay Ashworth wrote:
>> > From: "Robert E. Seastrom" <rs at seastrom.com>
>> > There is no reason whatsoever that one can't have centralized
>> > splitters in one's PON plant. The additional costs to do so are
>> > pretty much just limited to higher fiber counts in the field, which
>> > adds, tops, a couple of percent to the price of the build. 
>> 
>> Ok, see, this is what Leo, Owen and I all think, and maybe a couple others.
>> 
>> But Scott just got done telling me it's *so* much more expensive to 
>> home-run than ring or GPON-in-pedestals that it's commercially infeasible.
>
> Note, both are right, depending on the starting point and goals.

Data point, which makes the rest of this discussion moot:

Since telcos are historically myopic and don't build (much) extra
fiber into their plant to support future technologies, the only use
for existing fiber in the ground in passive optical applications is to
connect the COs.  There is not enough running out towards the
customers to support retrofitting it for PON.

Besides, there are regulatory issues with re-purposing existing
voice-plant-supporting assets for PON in places such as VZ territory
where the ILEC got a pass on legislated equal access applying to PON
builds.

Some more data that may inform your conceptualization - Split ratios
of 128 and 64 only work in the lab.  Proper engineering (overlap of dB
and bits/sec/customer) will dictate split ratios of 16 or 32
(depending on modulation scheme, and no, going to 10gbit modulation
doesn't help; you still have the link budget problem) last time I did
the math.

Still, the power budget improvements by not going with a single strand
active ethernet solution (which were another suggested technology and
has actually been deployed by some muni PON folks like Clarkesville,
TN) are huge.  Imagine a 24 port switch that draws 100 watts.  OK,
that's 4w per customer.  30k customers from a served location, that's
120kw ($13k power bill if you had 100% efficient UPSes and 0 cost
cooling, neither of which is true) just for the edge, not counting any
aggregation devices or northbound switch gear.

Back at NN, we discounted this as a technology almost immediately
based on energy efficiency alone.

Anyway, in summary, for PON deployments the part that matters *is* a
greenfield deployment and if the fiber plant is planned and scaled
accordingly the cost differential is noise.

-r

> Historically teclos have installed (relatively) low count fiber
> cables, based on a fiber to the pedistal and copper to the prem
> strategy.  If you have one of these existing deployments, the cost
> of home run fiber (basically starting the fiber build from scratch,
> since the count is so low) is more expensive, and much greater cost
> than deploying GPON or similar over the existing plant.
>
> However, that GPON equipment will have a lifespan of 7-20 years.
>
> In a greenfield scenario where there is no fiber in the ground the
> cost is in digging the trench.  The fiber going into it is only ~5%
> of the cost, and going from a 64 count fiber to a 864 count fiber
> only moves that to 7-8%.  The fiber has a life of 40-80 years, and
> thus adding high count is cheaper than doing low count with GPON.
>
> Existing builds are optimizing to avoid sending out the backhoe and
> directional boring machine.  New builds, or extreme forward thinking
> builds are trying to send them out once and never again.
>
> -- 
>        Leo Bicknell - bicknell at ufp.org - CCIE 3440
>         PGP keys at http://www.ufp.org/~bicknell/