Gigabit-over-copper VDSL successor G.fast signed off at last

Curb your enthusiasm: this is a short-run tech best suited to the basement

The long-awaited G.fast physical layer standard has been signed off by the International Telecommunications Union (ITU), improving the chance that the world will see standards-compliant, interoperable kit start to ship in 2015.

The ITU almost manages to work up some excitement about the announcement, reminding a grateful world that the standard enables speeds of “up to” a gigabit per second.

Back in 2013, the ITU would only go so far as to commit the technology to deliver hundreds of megabits per second, but that was before kit, chips or field trials existed to let it turn the switch to “boost”.

The December 5 statement from the ITU covers the PHY (physical layer) specs. In April of 2014, an accompanying standard, G.9700, set down spectral power density rules for G.fast to ensure that rollouts don't ruin radio transmissions.

The earlier standard requires local deployments to notch around FM radio broadcasts and avoid interference.

While there's bound to be a bout of schadenfreude over the ability to stuff a gigabit per second down copper, whether Australia ever sees a street rollout of G.fast is an unknown quantity at the moment, according to long-time DSL expert Dr Paul Brooks.

G.fast will arrive in apartments and office buildings pretty much as soon as kit's available, Brooks told The Register, because in-building deployments don't have to wait for the regulatory processes that nearly always accompany discussions about just who gets to use a telco's last mile of copper.

However, he said, the short reach of G.fast – its acclaimed gigabit capability – would constrain the number of households each node could serve in a suburban setting, making the economics uncertain even for small nodes.

A node's footprint might be as small as a dozen households, Brooks said, with no guarantee of getting enough takeup to justify itself. As a result, he believes in the short term there will be much more appetite for VDSL2 among providers. ®




Biting the hand that feeds IT © 1998–2018