nanog mailing list archives

Re: Muni network ownership and the Fourth


From: Jay Ashworth <jra () baylink com>
Date: Sun, 3 Feb 2013 09:34:58 -0500 (EST)

----- Original Message -----
From: "Robert E. Seastrom" <rs () seastrom com>

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.

It doesn't make it moot for me; I'm greenfield.

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.

Yeah, I sorta figured this.

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.

Hmm.  the optics don't have auto power control?

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.

I assume you mean "the cost diff between GPON plant and home-run plant";
that's the answer I was hoping for.

Cheers,
-- jra
-- 
Jay R. Ashworth                  Baylink                       jra () baylink com
Designer                     The Things I Think                       RFC 2100
Ashworth & Associates     http://baylink.pitas.com         2000 Land Rover DII
St Petersburg FL USA               #natog                      +1 727 647 1274


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