Re: Muni fiber: L1 or L2?

[Jason Baugher <jason () thebaughers com>]

I disagree. Loss is loss, regardless of where the splitter is placed in the
equation. Distance x loss + splitter insertion loss = total loss for
purposes of link budget calculation.

The reason to push splitters towards the customer end is financial, not
technical.


On Fri, Feb 1, 2013 at 2:29 PM, Scott Helms <khelms () zcorum com> wrote:

> Owen,
>
> You're basing your math off of some incorrect assumptions about PON.  I'm
> actually sympathetic to your goal, but it simply can't work the way you're
> describing it in a PON network.  Also, please don't base logic for open
> access on meet me rooms, this works in colo spaces and carrier hotels but
> doesn't in broadband deployments because of economics.  If you want to
> champion this worthy goal you've got to accept that economics is a huge
> reason why this hasn't happened in the US and is disappearing where it has
> happened globally.
>
>
> > Bottom line, you've got OLT -> FIBER(of length n) -> splitter ->
> > fiber-drops to each house -> ONT.
>
> So far you're correct.
>
>
> > All I'm proposing is making n really short and making "fiber-drops to
> each
> > house" really long.
> > I'm not proposing changing the fundamental architecture. Yes, I recognize
> > this changes the economics and may well make PON less attractive than
> other
> > alternatives. I don't care. That's not a primary concern. The question is
> > "can PON be made to work in this environment?" It appears to me that it
> can.
> >
>
>
> Here is where you're problems start.  The issue is that the signal *prior
> to being split* can go 20km if you're splitting it 32 ways (or less) or
> 10km if you're doing a 64 way split. AFTER the splitter you have a MAX
> radius of about 1 mile from the splitter.
>
> Here is a good document that describes the problem in some detail:
>
> http://www.ofsoptics.com/press_room/media-pdfs/FTTH-Prism-0909.pdf
>
>
> Also, here is a proposed spec that would allow for longer runs post
> splitter with some background on why it can't work in today's GPON
> deployments.
>
>
> http://www.ericsson.com/il/res/thecompany/docs/publications/ericsson_review/2008/3_PON.pdf
>
> --
> Scott Helms
> Vice President of Technology
> ZCorum
> (678) 507-5000
> --------------------------------
> http://twitter.com/kscotthelms
> --------------------------------