rcon wrote:japan has a similar technology right now
and what will they have when the NBN in completed in 10-15 years?
[/quote]
what you are forgetting is that the NBN is not internet technology, but internet infrastructure.
think about the history of data transfer over copper wire
first there was morse code/telegraphs
then phones (8kbit multiplexed onto 64kbit pipes)
then 16k dial up
then 32.64 dial up
then 128 ISDN
then 256 ADSL
now 1500 ADSL
and 24000 ADSL2+
this is ALL using copper cables and nothing more.
optic fibre networks can do a similar thing - all of the back haul data links are already optic fibre. most of these are made for much greater capacity than they deliver at the current time (when they lay optical fibre, they usually lay many many times what is required, because the expensive part is digging the hole, not laying the fibre)
at present, the bottle neck is the copper cables that go from the exchange (or the node at the end of your street) to the house.
the backhaul systems are easily upgradable - no further technology leaps, just more fibre. to say that they cant' handle it is a furphy, because these aren't really an issue to upgrade, just that there hasn't really needed to be an upgrade yet.