Last week, BT and Alcatel Lucent let it be know that their experimental broadband-over-copper technology XG.fast had achieved 1.8 gigabits per second over a 100m copper strand.

nbn TM , the company building Australia's national broadband network (NBN), has already trialled G.fast, the successor to VDSL and progenitor to XG.Fast, and scored 600 megabits per second in tests.

Nobody's suggesting XG.fast will be mature and available tomorrow. But the tests described above show, yet again, that copper will be a decent broadband medium for years to come. How decent? Let's assume that in the real world XG.fast delivers a gigabit per second. That's more capacity than many data centres require. It's enough capacity to handle several 4K video streams in both directions. It's a flood of bandwidth in which the tiny streams of XML smart homes will generate will always find a path, even if a home becomes home to 100 sensors.

Ideas like XG.fast may not satisfy those who insist Australia should build its NBN entirely out of fibre-to-the-premises (FTTP) connections. The argument for all-FTTP hinges on optic fibre having more or less infinite scalability. But we're now seeing that copper has a decent future, too.

Copper's future was hard to see when NBN mark one was conceived as an all-fibre affair. Copper's role is now clear, and clearly valid.

Australia's government and nbn now have a chance to kill off the fibre fetish argument in two ways.

The first is by releasing data to back the assertion that an all-FTTP NBN would truly be more costly and time-consuming to construct. To date, nbn has not convincingly addressed reports that it found ways to bring the cost of FTTP construction costs to levels comparable with fibre-to-the-node. If it can be proven that FTTN has been chosen for utility, not policy, FTTP fans will take a heavy blow.

The second piece of outstanding business is the state of Australia's copper networks. Those networks are assumed to be shabby and in need of so much short-and-medium-term remediation that FTTP will be a cheaper option even if implementation takes a little longer. Sunlight is needed here: comprehensive descriptions of the copper network aren't in public view.

If such data does become available, and shows the copper will be viable by the time XG.Fast and its successors come along, and beyond, it's hard to see the FTTP argument being viable for much longer. ®