[LINK] How fast is the NBN?

[Paul Brooks]

On 29/02/2016 11:13 PM, Bernard Robertson-Dunn wrote:
> On 29/02/2016 5:55 PM, David Lochrin wrote:
>
>> Just for the record...  Analogue or digital, 1980's synchronous modem or 2020 fibre, no matter what the technological cleverness any communication channel is subject to Shannon's Law.
> True.
>> This states that the maximum channel capacity is a function of transmitted power, bandwidth, and signal-to-noise ratio.
> True,
>
> However, Shannon's law is silent on the number of channels that a medium
> can carry. Fibre can carry many more channels than copper, coax or radio.
>
> Fibre modems, using Wavelength-division multiplexing can, currently,
> handle up to 160 channels. This means that a basic 10 Gbit/s system over
> a single fiber pair can be expanded to over 1.6 Tbit/s. [*]
>
> And just for the record, you don't have to change the fiber, just the
> boxes at either end.

True. And just for the record, current WDM systems are 100Gbit/s and 200Gbit/s per
channel, with 400Gbit/s and 1000Gbit/s coming from the labs.
That means a single fibre pair can be expanded to over 10 - 20 Tbps total capacity,
and growing.
Just by changing the boxes on each end - and often not even having to change any
amplifiers in the middle for long-haul runs.

In the context of access networks to homes - WDM-PON, which provides for a dedicated
optical wavelength channel per home, is commercially available already.

Paul.