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 <khe...@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 > -------------------------------- >
