Muni fiber: L1 or L2?

Sat Feb 9 13:35:40 UTC 2013

Masataka Ohta <mohta at necom830.hpcl.titech.ac.jp> writes:

> Robert E. Seastrom wrote:
>
>>> Let's assume 4:1 concentration with PON.
>> 
>> Why on earth would we assume that when industry standard is 16 or 32?
>
> That is because additional 4:1 concentration is usually at CO,
> which does not contribute to reduce the number of fibers in a
> trunk cable.
>
>> 16 is a safe number.
>
> Do you mean a splitter in field should be shared by 16
> subscribers?
>
> Then, with the otherwise same assumptions of my previous mail,
> total extra drop cable length for PON will be 204km, four times
> more than the trunk cable length.
>
> Thus, it is so obvious that SS is better than PON.

You're confusing fiber architecture with what gets laid on top of it.
Where the splitters go is entirely irrelevant.

Rule of thumb in the US is that 80% of the costs of a fiber build are
in engineering, planning, RoW acquisition, lawyers, etc.  Of the
remaining 20%, more of it is labor than materials.  Price per fiber
strand in the bundle is noise in the larger equation.

You have to pay for splitters in the PON architecture regardless of
where you put them, of course, so just bake that into the port cost
side of per-customer-served.

> OTOH, if concentration is 2:1 or less, it is, again, obvious that
> SS is better than PON, because of extra complexity of PON.

Again, home run central splitter vs. distributed splitter architecture
has nothing to do with PON being better or worse than a technology
that forces single strand all the way to the endpoint.

> So, 4:1 is the safe number to obfuscate lack of merit of PON.
>
> If you can read Japanese or FTTH is serious business of you
> worth hiring a translator of your own, you can find average
> number of subscribers sharing a splitter in field is 3.68,
> a little less than 4, from:
>
> 	http://itpro.nikkeibp.co.jp/article/COLUMN/20080619/308665/

Having actually been involved in building a business plan surrounding
this, I don't need to read Japanese to be able to tell you that the
outside plant engineering was clearly assigned to the madogiwazoku if
they're only getting a 4:1 split on average.

-r