FTTH Active vs Passive
dwhite at olp.net
Tue Dec 1 11:14:35 CST 2009
On 01/12/09 10:43 -0600, Justin Shore wrote:
> Active is the way to go. Passive is merely a stepping stone on the way
> to active. Passive only makes sense (in some cases) if you are 1) fiber
> poor and 2) not doing a greenfield deployment. If you have the fiber to
> work with or if you are building a FTTH plant from scratch go with
> active. The only real proponents of PONs are the RBOCs who are
> exceedingly cheap, slow to react, and completely unable to think ahead
> (ie, putting in an abundance of fiber for future use instead of just
> enough to get by) and some MSOs who don't dread and loathe shared
> network mediums like CATV and PON (whereas those from a networking
> background would never ever pick such a technology).
> Few vendors will ever admit that they interop with another vendor's gear
> though. They don't want you to buy their optical switches (which have a
> small markup) and someone else's ONTs (which typically have a much
> greater markup). In some cases even though that adhere to the standards
> to a point they diverge and go proprietary for things like integrating
> voice or video into the system. That could cause management and/or
> support issues for you at some point in the life of the product.
> Personally I'd go with a vendor that offers the complete solution
> instead of piecing one together.
> PON has some popularity in MDUs. The splits are easy to manage because
> they're all in one location. Bandwidth needs are typically on the low
> end in MDUs due to a lack of businesses (bandwidth being a severe
> future-proofing problem for PON). PON's biggest limitations for us is
> the distance limitations. We're deploying FTTH in the rural
> countryside, not in a dense residential neighborhood. PON has very
> specific distance limitations for each split and cumulative across all
> splits that make rural deployments extremely difficult. The price
> difference between Active and PON is negligible at this point and in
> many cases cheaper for active. Go with active for FTTH. You won't
> regret it.
All valid points. Deploying a strand to each customer from the CO/Cabinet
is a good way to future proof your plant.
However, there are some advantages to GPON - particularly if you're
deploying high bandwidth video services. PON ONTs share 2.4Gb/s of
bandwidth downstream, which means you can support more than a gig of video
on each PON, if deploying in dense mode.
Another big advantage is in CO equipment. A 4-PON blade in a cabinet is
going to support on the order of 256 ONTs.
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