From DSL to FttN, G.FAST, Fttdp, XG-FAST – building the NBN the tortuous way

In September 2016, NBN Co indicated its interest in a technology known as XG.Fast, it is a next level up from the G.Fast technology they started to trial in 2015 and it also needs to be seen in the yet still bigger picture of Fttdp (fibre to the distribution point).

The development and deployment of these technologies is still in an early phase and in all reality nothing major is going to happen until after the completion of the current NBN 1.0 roll out which will not be before 2020.

Key issues with all of these elements to the government’s MTM policy is if these technologies are indeed reliable to be deployed on a mass scale – we are taking in excess of 6 million homes here – but even more affordable will the deployment of these services still result in affordable high-speed broadband services across the country.

The other question raised by all these band aid solutions is whether the end result will be better and cheaper than the original ‘do it once, do it good’ FttH approach.

NBN’s ‘’ G.Fast

In late 2015, NBN Co revealed that it was conducting trials of G.Fast – a technology that allows very fast speeds over short copper loops, with according to their analysis “commercial deployment being highly likely.”

G.Fast uses a very large swathe of signal processing bandwidth on a short twisted pair to achieve very fast speeds.

In Australia some 70% of the population was within 350m of the cabinets or pillars where FTTN nodes will be co-located by NBN.

According to reports from NBN Co in 2015, it could still be two years before it is in a position to launch G.Fast commercially; and even then the company is unsure if , how, and when it might want to deploy the technology. By that time most of the developed world will have moved even further towards FttH and in one way or another G.Fast will have to fit into that final picture.

Part of the problem is that the technology uses a much larger frequency range of signal processing bandwidth than other copper technologies over a much shorter copper length. Some of these overlap those used by commercial VDSL, so running both technologies together causes interference. Another problem is the extra power supply that is needed for the nodes that need to be deployed within this technology.

While this can all be resolved it only adds further to the complexity of the already multi-technology mix that the company is using for the rollout of the NBN.

Remember the multiple technology mix for the various railway systems Australia used to have?

Back to G.Fast, according to the company they have a great deal more work ahead of them before they can proceed to a commercial launch. Further trials are taking place 2016, this time in combination with XG.Fast (see below). Technically they expect to be ready for commercial launches in 2017, but if they then decide to use the technology extensively it will take many years to move it into residential markets – basically another rollout, with all the associated costs attached.

This development also depends on the availability of commercially priced hardware needed, to make such a rollout is indeed cost-effective. Currently it seems most likely that it will be a business product offering rather than a residential one.

In the meantime the hardware industry, sensing the desperation of the telcos’ need to start improving their broadband networks, are talking up the G.Fast technology. However at this stage – and at least in a commercial sense – that technology is still more hype than reality.

In the end these vendors can make these technologies work – but at what cost? And what does it mean for their customers who will eventually have to move on from G.Fast into a more final solution with FttH?

In general what this means is that the telecoms operators will only deploy these technologies very selectively, in areas where it doesn’t yet make sense to roll out FttH for either commercial or technical reasons. It is highly unlikely that G.Fast will see mass deployment.

XG.FAST – yet another addition to the MtM, but also still years away

In September 2016 NBN Co and Nokia announced their interest in the XG.FAST technology, paired with Fttdp, with trial speeds delivering from 5Gb/s to lab results of 8Gb/s over twisted pair copper lines.

In order to deploy this new technology NBN Co would need to drive fibre deeper into the network – well beyond the FttN box (which will basically become obsolete), running it to the edge of the premises / driveway using a technology known as fibre-to-the-distribution-point (FttDP) with XG.FAST using only the last 30-100 metres of copper into the premises.

The quality of the service will depend heavily on the quality of the underlying copper cables, so there won’t be a ubiquitous speed guarantee.

NBN Co is undertaking lab trials, promising to deliver speeds ‘up to 5Gb/s and beyond’ – with trial speeds potentially in excess of 5Gb/s on a pair of copper lines. XG.FAST is yet another next generation of copper technology — a further development of G.FAST. However the new technology will not be ready for commercial deployment for several years. After completion of the current NBN around 2020 the first next step will be to upgrade the FttN network with G.FAST, and XG.FAST will follow again after that.

NBN Co is exploring the potential for it to use these high speeds to the six million-plus premises on the NBN network that will initially be served by either fibre-to-the-node (FttN) or fibre-to-the-building (FttB) networks.

While any new developments beyond FttN are very welcome, as with all new technologies reliability will be key – and, even more importantly, its affordability. As also mentioned above, the question that comes up with all these additional new technologies that apparently are needed to provide a better broadband service is – why not do it right the first time with a proper FttH network?  Even if it is proved to work XG-FAST will not eliminate the need to replace the copper wires in the FttN network in 10 to 15 years’ time.

It looks as though we are doing it the long way round, going from DSL to FttN then G.FAST, Fttdp followed by XG.FAST, and then most likely to FttH.

At that point it would be reasonable for people to question why it was done via this tortuous route.

Paul Budde

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