cyril7: Hi, I sounds to me like your source is mistaken. If we are assuming GPON (which is what TelecomNZ and most other telcos are deploying) then the down link is 2.4Gb/s and uplink 1.2Gb/s, this is shared with upto 32 others, ie there is a passive optical splitter that splits the single GPON feed to 32 users. That 2.4Gb/s is therefore deliverd to all users, however as its a shared 2.4Gb/s then thats a 75Mb/s uncontested bandwidth to each user.
Current ONT's that the hardware on the side of your house that accepts the fibre and provides copper ethernet, only support fast ethernet, hence 100Mb/s max, so there should be no problem in real world use to get that full 100Mb/s with some contention (none really).
As for distance, current PON technologies have a 28dB link margin, so that means a 32way split network can go 20km, if there are less splits per GPON then it can go significantly more. 20km covers a bit area in reality you are going to have OLT's (head end bit) distributed closer than that. Unlike DSL it does not reduce in speed with distance, this is fibre technology.
Into the future there is 10GPON on the horizon which is 10x faster and other technologies past that being looked at.
Obviously this is just discussing the speeds and capabilities in the local loop, what is above that is another discussion.
I misunderstood, the restriction on speed is not technical but rather cost and Overall network capacity.