Home & Office

​ITU approves G.fast DSL high-speed broadband standard

The International Telecommunications Union has approved the G.fast broadband technology standard, allowing it to become broadly commercially available in a bid to help service providers deliver speeds over DSL of up to 1Gbps in mixed-technology broadband delivery scenarios.
Written by Leon Spencer, Contributor

Members of the United Nations' International Telecommunications Union (ITU) have reached a final approval of G.fast, the broadband standard that is designed to deliver access speeds of up to 1Gbps over existing copper telephone wires.

G.fast is a digital subscriber line (DSL) standard that is designed to allow speeds of between 150Mbps and 1Gbps -- depending on loop length -- for standard local subscriber lines shorter than 250 metres.

The ITU, which allocates radio spectrum and develops technical standards, said that the standard meets service providers' need for a complement to fibre-to-the-home (FttH) technologies in scenarios where G.fast proves the more cost-effective strategy.

G.fast, within fibre-to-the-distribution point architecture (FttDP), combines elements of fibre and DSL. The ITU said that within 400 metres of a distribution point, G.fast provides "fibre-like speeds", and helped result in infrastructure cost savings for service providers.

"The time from G.fast's approval to its implementation looks set to be the fastest of any access technology in recent memory," said ITU secretary-general Dr Hamadoun I Touré. "A range of vendors has begun shipping G.fast silicon and equipment, and service providers' lab and field trials are well under way."

The development of the G.fast standard has been coordinated with the FttDP system architecture project of industry consortium, the Broadband Forum. ITU and the Broadband Forum have been working in collaboration to help expedite the placement of G.fast solutions in FttDP deployments.

"The Broadband Forum is working closely with the ITU to ensure compliance with the G.fast standard, and certify chipsets and equipment," said Robin Mersh, CEO of the Broadband Forum. "We have already set our first plugfest for January 2015."

The Broadband Forum has been developing a test suite and certification program for G.fast systems, with the suite expected to provide for interoperability, functional, and performance testing.

A beta trial of the certification program is planned for mid-2015, and certified G.fast implementations are expected to appear on the market before the end of 2015, the ITU said.

The approval of the G.fast standard comes as the Australian government works to champion the use of existing copper phone lines in its multi-technology mix model for the rollout of the country's high-speed National Broadband Network (NBN).

In November, the nation's broadband network builder NBN Co ended its initial plans to roll out fibre to the premises (FttP) to 93 percent of Australian premises, mandating that fibre to the node (FttN) should be the default technology choice.

Under this new plan, the 3 million premises covered by the hybrid fibre-coaxial (HFC) networks owned by Telstra and Optus would likely get connected to an "upgraded" HFC network on the NBN, and those already in the fixed-wireless and satellite footprints would stay on those technologies.

NBN Co is currently using vectoring technology in FttN, but has said that G.fast may be used in the future. A move to G.fast would require NBN Co to replace more of the existing copper with fibre.

In September, researchers from British telecommunications services company BT claimed that they could deliver ultra-fast broadband at up to 1Gbps per second using the G.fast technology.

"During the G.fast trials, downstream speeds of around 800Mbps were achieved over a 19-metre length of copper, combined with upstream speeds of more than 200Mbps," BT said in a statement at the time. "Impressive speeds of around 700/200Mbps were also achieved over longer lines of 66 metres, a distance that encompasses around 80 percent of typical connections."

Editorial standards