Re: Show me the hardware.
@AC
Here's the deal . . .
FTTN means fibre from the exchange to multiple streetside nodes, with each node then connected to a bunch of subscribers - 100-300 - via a non-fibre connection such as twisted-pair or coax. I could be wrong on the numbers but it's not really important for the moment. This much is largely understood.
What is less-widely understood is what FTTP entails. There are several different ways to do this and many people believe that there would have been fibre directly from the Exchange to each and every home. Not so. While this is an option, the old NBN plan was for a GPON - Gigabit Passive Optical Network.
This involves a passive 'splitter' that splits the optical signal out to multiple 'last mile' fibres connected to the end points. If one were to draw FTTN vs FTTP (GPON) then they would look similar on the surface.
There are two big differences, however, which is that a GPON FTTP splitter services fewer endpoints (32 is the standard) and is passive. This is a big advantage as all the active electronics in a FTTN node makes them more expensive to build and maintain.
As regards the first difference - the number of endpoints - this is the number per splitter and a node may contain multiple splitters. This is a flexible situation. You can drop a (very small) 32-node splitter in an existing pit without any problems - they are small and passive. Or, you can set up a cabinet and add as many splitters as you like.
Here is an image of a single, 32-port splitter, of the type that could be dropped in a pit. (In a suitable enclosure.)
Larger, more manageable units resemble network switches and these are installed in (usually above-ground) cabinets. As there is no real maintenance overhead nor distance restriction on the 'last mile', deployment is very flexible, so one can have small, medium or large cabinets depending on requirements. You can strap 'em to telephone poles if you like.
This is in contrast to the FTTN nodes, which require complicated, active electronics to convert the incoming optical signal into an electrical one and off to VDSL (essentially making each node an exchange) or coax. For these units to perform well using VDSL, which is the main push, they must be no more than around 400m from any given endpoint, due to the attenuation of copper and the subsequent sharp fall-off of VDSL speeds*.
So, what happens if one wants to transition from a FTTN to a GPON FTTP?
The biggest issue is that you no longer need all those active nodes. You still need somewhere to house the GPON splitters, of course, so the node cabinets could be re-used, but the upgrade would have to happen in parallel sou you'd need enough spare room in there. If you have a look at a FTTN node, you see that there isn't all that much room, though the small size of the GPON splitters and the required close-spacing of FTTN cabinets to achieve decent speeds means that you wouldn't need to put too many splitters in each cabinet.
BUT, remember that the ratio is 1:32 for GPON, meaning 1 incoming fibre from the exchange split to 32 endpoints. So, you need to lay more fibre loops to each of the nodes. And, as these nodes are numerous, that's lots of separate runs of small bundles, rather than one run of a larger bundle if you build a new GPON node. But again, that's a new node - new infrastructure!
But, once you've cut-over, what do you do with all that obsolete hardware? You've got heaps these huge cabinets - far larger and more numerous than are now needed - either filled with quiescent electronics or large empty spaces. That's a wasted investement - it serves no purpose now.
BUT, it's not just the hardware in the nodes that needs replacing - you also have to replace everyone's (now obsolete) VDSL/coax 'modems'! And again, that old hardware is useless now.
But, there's another problem, and that is whatever commercial arrangements have been made for third party ISPs, which will be delivering their offerings over combinations of twisted-pair and coax. I can't speak to those but you would imagine that it wouldn't be a smooth transition.
And, of course, you still have to actually lay the fibre to the end points.
* - Just as ADSL2 quickly falls to ADSL speeds, so too does VDSL fall to ADSL2 (and then to ADSL) speeds.