First homes connected in BT G.fast trial

Credit: chrisdorney/Shutterstock.com

The trial, which will run for the next six to nine months, will see around 2,000 homes and businesses connected to the network using "various methods" of deploying the technology involved.

This is just the first such trial, with a second similarly sized project in the Gosforth area of Newcastle-upon-Tyne, and a much smaller "technical" trial planned in Swansea, due to begin next month.

People being connected to the network will have a choice of eight providers including Zen Internet and AAISP, following BT's open invitation to other ISPs to join the trial.

G what?

G.fast's appeal to BT is pretty clear. Like BT's existing fibre broadband, it relies on a mixture of fibre optic cable and copper wiring.

This fibre to the cabinet (FTTC) arrangement is far cheaper to deploy than pure fibre to the premises (FTTP) of the sort being offered by Hyperoptic, Direct Save, and Sky and TalkTalk; it's also less expensive than using fibre optic and coaxial cable as Virgin Media do.

The problem is that it's the final part of the connection - the copper or coaxial cable - where the speed of the connection suffers.

It's well known that the further away from the cabinet or exchange a customer is, the slower the speeds they'll be able to get.

G.fast combats this in two ways. Firstly, it maximises the amount of data that can be carried over the wire - partly by using a much broader chunk of the radio spectrum than ordinary FTTC copper wires do.

The extra spectrum requirements mean the lengths of copper wire involved must be much shorter than with standard fibre.

So the second part of G.fast relies on bringing the fibre optic cable closer to the buildings.

Instead of running as far as the familiar on street cabinets, which provide us with up to 38Mb and up to 76Mb FTTC services, it'll continue to telegraph poles and junction boxes - what's known as fibre to the distribution point (FTTdp).

The speed of the connection still suffers the further we get from the distribution point, but BT's Colin Bannon said in June that 300Mb was still deliverable at a distance of 350 metres.

When they first announced the pilot schemes earlier this year, BT said that when the copper wire was 19 metres long, they were achieving download speeds of up to 800Mb and uploads of up to 200Mb.

Infinity has a limit

So the plan at present is to offer connections of up to 500Mb, with a national rollout of the service beginning as soon as the end of next year - should the trials go well.

That would mean G.fast could provide a faster, cheaper - and much more widely available - alternative to BT's stalled fibre on demand (FTTPoD) service, known as Infinity 3 (up to 160Mb) and Infinity 4 (up to 330Mb).

At present neither is being sold to new customers - partly because they're incredibly expensive to install.

Rather like standard fibre, Infinity 3 and 4 rely on both the exchange and street cabinets being compatible.

However, the number of such exchanges is in the low hundreds; to put that in context, there are more than 5,500 exchanges nationwide.

If a user is covered by one of those exchanges and their nearest cabinet is up to scratch, BT themselves reckon installation would cost at least £1,100.

So running alongside the G.fast pilot is a smaller scheme aimed at improving that FTTPoD service, in which it would provide speeds of up to 1Gb for a (hopefully) more affordable price.

And the competition?

That's important for BT and Openreach if they want to keep ahead of the competition; after all, only this month Virgin Media announced that they would be increasing the speeds available to their customers - free of charge - from October.

They're making people wait until October before revealing what their new top connection speed will be, but earlier this year some customers reported receiving speeds of up to 300Mb, which the ISP admitted were the result of a fresh round of trials.

And while BT can only hope to start rolling out G.fast by the end of 2016, Virgin have said they expect their upgrade to be complete closer to the start of the year.

That's on top of Project Lightning, in which they aim to expand their network to roughly 60% of the population by 2020.

It's possible that this is just the beginning of the adventure for Virgin Media customers.

As mentioned above, the ISP use a combination of fibre and coaxial cable to bring services to our homes, using what was once simply a cable TV network.

The technology that allows these cables to deal with high speed data is known as Data Over Cable Service Interface Specification, or DOCSIS.

Since its introduction in 1997, DOCSIS has evolved, with faster connections among the various improvements.

DOCSIS 3.0 can reach up to 400Mb, although that's under ideal circumstances - hence Virgin's current top tier service being up to 152Mb.

But the newest standard, DOCSIS 3.1, is thought to be able to provide speeds of up to 10Gb under ideal conditions - and it's thought home users could benefit from services ranging from 500Mb to 1Gb as a result.