Re: Muni fiber: L1 or L2?

[Scott Helms <khelms () zcorum com>]

Jason,

Loss is loss, but that's not all that we have to deal with here inside of
how PON works.  I can tell you that not a single manufacturer I've worked
with says anything differently.


On Fri, Feb 1, 2013 at 4:03 PM, Jason Baugher <jason () thebaughers com> wrote:

> 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
> > --------------------------------


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