FiOS's one mistake? in Fiber Optic http://www.dslreports.com/forum/r14808885 en Fri, 27 Nov 2009 19:35:12 EDT Fri, 27 Nov 2009 19:35:12 EDT Re: FiOS's one mistake? http://www.dslreports.com/forum/remark,14923106 ronpin : I appreciate why a fiber architect would have selected the centralized splitter option -- before now :)

To date, nobody has offered a cascade-specific vastly cheaper conduit option. That changes everything yes?

How many 1x32 OLT ports will $35,000 of savings per-mile buy? (really, how many?) related savings from static outside plant infrastructure? (no on-demand splitter changes, smaller maint. staff) Premise work only (outsourced). Let's ignore the miles of extra fiber -- saved here as well.

I'm saying that the massive savings enabled by 1/4" surface-groove/curb-line tiny coated copper tubes for air-blowing is well-worth pre-installing a 1x32 OLT port -- as required in the cascaded-splitter architecture.

As long as a 1x32 OLT port is substantially less than $35,000 ea. -- we have a substantial savings in the cascaded option.
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High ideals breed lowly hypocrites]]> http://www.dslreports.com/forum/remark,14923106 Thu, 01 Dec 2005 09:56:46 EDT Re: FiOS's one mistake? http://www.dslreports.com/forum/remark,14922479 tschmidt : I believe Verizon is using a lot of preterminated fiber. If so that means conduit/innerduct must be relatively large to pass the connector regardless of how many fibers are used.

I assume Verizon looked at the tradeoff between Capex and Opex and decided a centralized splitter cabinet optimized OLT loading and reduced Opex as user and speed mix changes over time.

It is a lot easier to go to one location and change splitter allocation as needs change. When the time comes to upgrade to next generation PON conversion will be a lot easier if all that is needed is to add a few nexgen PON OLT line cards, upgrade a few customers to new spec and modify splitter cabinet crossconnect.

This is also much the same outside plant arrangement used with copper so the OSS system that manages copper is easily adaptable to fiber.

I'm just guessing, I have no knowledge of why Verizon is doing what they are doing, other then I have to assume a lot of smart people modeled various alternatives and decided on balance this was the best.

/Tom]]> http://www.dslreports.com/forum/remark,14922479 Thu, 01 Dec 2005 07:39:34 EDT Re: FiOS's one mistake? http://www.dslreports.com/forum/remark,14916219 ronpin :
said by PONman See Profile :

or this: There is a 1x2 splitter before the 1x32 splitters, and due to there only being 32 users, the system will work correctly (assuming the optical loss isn't too much)
Your right-on for the current "Sub-Division Centralized Splitters".

It's the "or this:" (above) is actually the "other" diagram in the PDF link above -- the "cascaded splitter design". It uses an initial 1x8 splitter resulting in 1x4 distribution splits.

"All Things Being Equal" -- centralized splitters win hands-down. It's the "equal" part that screws-up the equation. A "tiny-tiny" subsurface copper "air-blow" conduit that serves 320 users in a static cascaded-splitter design (see diagram) is "much much" cheaper than a 2" horizontally bored conduit (minimal space to accommodate the hundreds of homeruns required in a centralized splitter design)

Horizontal boring is expensive -- about $10 foot -- cheaper if your Verizon.

Alternately, Labor + 1/4" coated copper-conduit is ~about $3 foot -- a whopping 70% cost reduction -- $35,000 per mile -- all because you opted for a cascaded-splitter design (above).

Now, we just have to get over accepting that effectively pre-subscribing 320 passings inside of 10 1x32 feeder fibers (terminated in 18-strand air blown fiber cables near a RT,CO or local cross connect) is a bad-thing - not if it's actually cheaper.

It is the last item above that also requires a clever marketing model -- which is beyond our scope here :)

The savings is so great that you can now afford to split every home to a final 1x4 fiber/FTTP drop fanout -- and still save money over the current generation of buried conduit.
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High ideals breed lowly hypocrites

Cascaded Splitter Option
]]> http://www.dslreports.com/forum/remark,14916219 Wed, 30 Nov 2005 14:06:13 EDT Re: FiOS's one mistake? http://www.dslreports.com/forum/remark,14915860 PONman : I guess I'm sort of confused about this plan. Looking at Fig 4 it looks like the plan is either this: Run x number (however many will serve the community at full capacity) of fibers to the centralized hub. Then run individual fibers from the hub to all the homes in the community. Start out using only one of the fibers back to the CO connecting it to a 1x32. Connect users to that splitter as they sign up. Once the 33rd customer signs up, put another 1x32 splitter in the hub and connect it to the second fiber back to the CO and install a new OLT port back at the CO.

or this: There is a 1x2 splitter before the 1x32 splitters, and due to there only being 32 users, the system will work correctly (assuming the optical loss isn't too much)

So whats the real deal here? Could someone explain to me what this Fig 4 looks like from a physical level but more importantly from an optical level, end to end. Also, what is Verizon doing today?
Click for full size
Fig 4
]]> http://www.dslreports.com/forum/remark,14915860 Wed, 30 Nov 2005 13:14:46 EDT Re: FiOS's one mistake? http://www.dslreports.com/forum/remark,14835587 jmich : Not a mistake from contrator$ point of view.]]> http://www.dslreports.com/forum/remark,14835587 Fri, 18 Nov 2005 17:29:08 EDT Re: FiOS's one mistake? http://www.dslreports.com/forum/remark,14816654 ronpin : :)

Ooops -- Forgot to include the credits! ("fair-use")
]]> http://www.dslreports.com/forum/remark,14816654 Wed, 16 Nov 2005 09:02:54 EDT Re: FiOS's one mistake? http://www.dslreports.com/forum/remark,14816625 ronpin : Great article -- but it's not aware of any cost savings with distributed splitter/smaller conduit -- which alter his "equation" (math is a dangerous thing :) )
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When Clinton lied -- no one died.
]]> http://www.dslreports.com/forum/remark,14816625 Wed, 16 Nov 2005 08:55:21 EDT Re: FiOS's one mistake? http://www.dslreports.com/forum/remark,14816569 ronpin :
said by wtffiber :

there was an article in OSP that explained that the centralized splitters is the most cost effective way to go. That way the optical cards in the CO can be addad as needed and every channel on them used. If you have 100 cards with 4 channels used on each of them, thats a bigger waste of $ than putting fiber in the ground.
The OSP article ( »www.ospmag.com/issues/article/?a···00000353 ) has no way to know about the tiny cheap conduit that is enabled by the cascaded splitter design...

EDIT: Better PDF version with graphics -> »www.bechtel.com/PDF/BIP/39314.pdf
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When Clinton lied -- no one died.]]> http://www.dslreports.com/forum/remark,14816569 Wed, 16 Nov 2005 08:43:16 EDT Re: FiOS's one mistake? http://www.dslreports.com/forum/remark,14816440 ronpin :
said by eXodus See Profile :

...once out of the 1x32 splitters and the FDH, it runs to a "splice box" (i guess you can call it that) that has either 4 or 6 connectors to be run from that box to the ONT. So you dont run an individual strand of fiber from FDH to ONT only from pole to ONT. The longest drop I have heard used was 1000ft. which isin't long at all...
'Same thing as "one strand" (strands do get spliced :) )

Maybe I should also offer that FiOS's "mistake" is more like a choice between the "lesser of 2 evils" (I suggest they chose the greater evil). FiOS went to great expense to save buying hardware "now". I say save the great expense [of the bloated conduit created in the FiOS architecture] and use that money to buy the hardware you'll ultimately need anyway. That choice enables the use of distributed splitters which in turn enables the use of a tiny cheap sub-surface conduit.

So-what if 30% of your OLT ports are never fully loaded with 32 users on each strand? would you prefer to have spent that same money on $10/ft. bloated conduit that could never earn a penny for you?

I think the lean-times the early FTTP vendors went thru gave them some "conventional wisdom" (like centralized splitters) that was good advice for the early entrepreneurial FTTH startup's -- but should not have been carried-over into the RBOC world where the huge customer base and corporate capital allows for some economy-of-scale (an entrepreneur would've done his "own" horizontal boring with day-labor for maybe the same cost as the tiny conduit -- thus making centralized splitters pay-off)
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When Clinton lied -- no one died.]]> http://www.dslreports.com/forum/remark,14816440 Wed, 16 Nov 2005 08:16:47 EDT Re: FiOS's one mistake? http://www.dslreports.com/forum/remark,14815181 eXodus : This was brought up before. Actually once out of the 1x32 splitters and the FDH, it runs to a "splice box" (i guess you can call it that) that has either 4 or 6 connectors to be run from that box to the ONT. So you dont run an individual strand of fiber from FDH to ONT only from pole to ONT. The longest drop I have heard used was 1000ft. which isin't long at all. They only run the drop when you get fios installed, not during the build.
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I love my FiOS!
-eXodus]]> http://www.dslreports.com/forum/remark,14815181 Wed, 16 Nov 2005 00:10:21 EDT Re: FiOS's one mistake? http://www.dslreports.com/forum/remark,14814317 anon : there was an article in OSP that explained that the centralized splitters is the most cost effective way to go. That way the optical cards in the CO can be addad as needed and every channel on them used. If you have 100 cards with 4 channels used on each of them, thats a bigger waste of $ than putting fiber in the ground.]]> http://www.dslreports.com/forum/remark,14814317 Tue, 15 Nov 2005 22:03:27 EDT Re: FiOS's one mistake? http://www.dslreports.com/forum/remark,14810173 53059959 : ^ what he said]]> http://www.dslreports.com/forum/remark,14810173 Tue, 15 Nov 2005 12:46:38 EDT FiOS's one mistake? http://www.dslreports.com/forum/remark,14808885 ronpin : Verizon's decision to go-with 32x1 "subdivision-centralized" splitters for their BPON FiOS architecture drove up buried conduit installation CAPEX by ~$35,000 per mile.

Why?

Centralized 32x1 splitters means that each home to be "passed" needs an individual fiber to be "home-run" from the 32x1 splitter box -- for up to a mile -- to a splice point near the home for the final drop. That means as many as 200 fibers, or more, in any one conduit. That means a larger conduit. That means more money (and a lot more fiber)

Verizon reportedly pays somewhat less than the going-rate of $10/ft for horizontally bored 2" buried conduit installation. Had they decided to use a "distributed splitter" layout -- they could have used a tiny (1/4") air-blown sub-surface conduit that cost only 1/3 as much.

The tradeoff? centralized splitters allow only active/subscribed homerun fibers to actually be attached to an active splitter. That means you can get-by with fewer splitters and [32x1] OLT ports (at the CO) -- as your subscriber base grows. The price for that luxury is the $10/ft conduit. The folly is that you'll eventually need the OLT ports anyway -- if your successful -- and yet you will have paid $35,000/mile too much for your conduit (not to mention the miles of extra fiber strands).

Alternatively, distributed splitters allow strand reuse after 32 home "sets". That means an 18 strand air-blown fiber can serve 320 homes! (trust me on the strand mapping). That means that a tiny 1/4" sub-surface/shallow conduit can be used -- for about $3/ft.

The tradeoff? All splitters and OLT ports that will ever be needed must be bought upfront. Don't worry, the $35,000/mile you just saved will be more than enough to pay for the extra splitters and ports -- and you'll have to buy them anyway -- eventually. So, for about the same "upfront money" -- you save money in the long-run since no more OLT ports or splitters need to be added on-demand later.

Bottom-line, you wind-up spending about $225 for conduit per passing -- instead of $750 on conduit per-passing. If Verizon had planned-on success they would've enjoyed the massive long term savings in a distributed splitter architecture.

I sure hope SBC, BellSouth and Qwest get-it. FTTP by these other telco's seems stymied -- apparently due to the $750 per passing conduit costs. Now that the home ONT costs are down to ~$300 -- it does seem bizarre that conduit should cost more than the ONT. Distributed splitters solve that cost problem -- and save massive $money in the long run.]]> http://www.dslreports.com/forum/remark,14808885 Tue, 15 Nov 2005 09:29:28 EDT