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BT Claims Future G.fast Broadband Delivers 300Mbps Speeds at 350 Metres

Thursday, June 11th, 2015 (9:46 am) - Score 5,864

The CTO of BT’s Wholesale division, Colin Bannon, has revealed that their future G.fast (ITU G.9701) broadband technology has also been tested on longer copper lines of 350 metres and the operator found that at this distance it was still able to deliver Internet speeds of 300Mbps.

Earlier this year BT unveiled tentative plans for a decade long deployment of G.fast technology, which will start around 2016/17 and should eventually make download speeds of up to 500Mbps available to “most homes” across the United Kingdom (here and here). G.fast is theoretically capable of 1000Mbps+, but you’d have to be practically sitting on top of a node to get that.

The solution is loosely similar to the operators current 40-80Mbps capable Fibre-to-the-Cabinet (FTTC) technology, except that it requires significantly more radio spectrum (FTTC 17MHz vs G.fast 106MHz+) and must thus operate over a much shorter run of copper cable (ideally less than 200 metres).

As such any homes or businesses that exist further away than the ideal distance (BT has yet to set a firm upper threshold for this) would require G.fast to be used in combination with other methods (e.g. FTTdp / FTTrN), which shorten the final copper run by effectively bringing high capacity fibre optic cable even closer to homes. After this the service would be distributed from smaller nodes, which could be installed on top of telegraph poles, inside street cabinets or even underground.

g.fast broadband bt network diagram

BT are currently preparing a new round of major G.fast trials in three locations – Huntingdon (Cambridgeshire), Gosforth (Newcastle) and a smaller scale technical trial in Swansea (Wales). But until now most of BT’s early G.fast trials (here), at least those we’ve heard about, have only spoken about the technology’s performance over short distances (i.e. 100 metres of copper or less).

The early alpha trials revealed that initially you’ll probably have to live within around 50 metres of a G.fast distribution point in order to receive the promoted 500Mbps, while you’d need to be sitting at about 20 metres for 1000Mbps (231Mbps upload / 786Mbps download) and the speed falls away quickly as the copper line distance grows.

gfast trial bt results

The above tends to reflect a best case scenario, where G.fast has access to its entire spectrum and doesn’t have to share some with existing FTTC (VDSL) services as that can have a hugely negative impact on performance. But we’ve heard precious little about what BT’s G.fast trials can do beyond 100 metres, until now.

However the figures given by Bannon, which indicated that strong speeds of 300Mbps were possible at 350 metres, are also reflective of early trials and thus another best case scenario (note: we are not certain if this figure is also aggregate performance or not). In the real world it won’t be quite so easy.

Never the less BT’s results are impressive because some early predictions had indicated that you’d need to be a lot closer (just below 200 metres) in order to get G.fast to deliver 300Mbps, yet BT’s early trials seem to now indicate that the technology may have even greater reach than first thought. Mind you Israel-based semiconductor company Sckipio has already hinted at this before (here), although their kit wasn’t being used in the BT test.

Unfortunately the original Lightreading article doesn’t say much more than that, except to confirm BT’s view of G.fast as an “economic game-changer” and they’re “aggressively pursuing additional standards” so that the final deployments will “get a lot better” than seen in their un-optimised trials. Everything else revealed by Bannon’s speech was already touted by BT’s Chief Network Architect, Neil McRae, in April (here).

The speed point of 300Mbps is important since this appears to be the target performance for BT’s forthcoming G.fast trials, perhaps because if they can deliver the service at 350 metres in the real-world then that would be very economically viable (i.e. installing the kit inside or alongside existing FTTC street cabinets to cover millions of lines within that distance).

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By Mark Jackson
Mark is a professional technology writer, IT consultant and computer engineer from Dorset (England), he also founded ISPreview in 1999 and enjoys analysing the latest telecoms and broadband developments. Find me on Twitter, , Facebook and Linkedin.
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61 Responses
  1. Steve Jones says:

    If 300 Mbps can really be delivered over 350 meters, that means it would be launched rather quicker than we might think for those customers who are within range of an existing cabinet. Perhaps by adding a second cabinet nearby or, maybe, by a refresh to the existing cabinets so they can provide both VDSL and g.fast.

    It will probably only serve a minority of existing customers, but it might explain some of OR’s statements on this. Of course that would leave the much more expensive problem of dealing with longer lines, but I suspect BT would love to be able to make a product available, if only to a minority, as early as possible. It does, of course, mean vectoring will have to be sorted out as g.fast is unworkable without it.

    1. TheManStan says:

      Plus the additional ECI ahrdware compatability headache…

    2. Carl says:

      There is no ECI compatibility headache. Just run G.fast at >17MHz.

    3. TheManStan says:

      Fair point notching does allow co-existance, but you lose about 100m of usable range so the amount of properties captured diminishes.

    4. Carl says:

      Little other option.

      How is an FTTC DSLAM going to know which of the G.fast nodes it’s vectoring with for a particular line without software changes, and where’s it going to get the 40Gb ports it’ll need to perform that vectoring?

    5. MikeW says:

      Unless, of course, they replace the FTTC node with one capable of supporting both G.fast to near properties and VDSL2 to distant properties.

      Or perhaps this could be achieved with G.fast line cards being created for the existing nodes.

  2. FibreFred says:

    What about 500 meters or so… I’d like to know that 🙂

  3. DTMark says:

    Does anyone really believe this is anything other than a “trophy technology” which will never see the light of day anywhere but in a small number of locations unless the well-proven method of “getting the government to force the taxpayer to buy it for BT” is able to be utilised?

    That we’re really going to see these nodes within maybe 150m of “most properties” to get the 500Mbps? Anyone want to have a guess at how many nodes that represents..

    1. FibreFred says:

      Why not, they have to keep moving. It will no doubt take the same approach as FTTC

      G.Fast for commercial viable areas under BT’s own funded rollout

      Then should the government “need” to increase beyond what has been provided under BDUK I guess another round of BDUK would take place where providers (including BT) can bid.

      I definitely believe it will happen yes

    2. DTMark says:

      All this trial is doing is validating the design of the cable network. It teaches us nothing new. That you can’t put serious bandwidth down any length of copper. The cable network designers knew this in the 1960s hence co-ax and lots of cabinets. Really, all it shows is how unprepared BT is for the future and how much work is needed for it to remain relevant to needs.

      “The same approach as FTTC” would be to begin to roll out something at least 15 years too late and even then only after there’s a whiff of government money coming their way, and then game the government and the tax payer.

      And while any roll out of this might give people in cabled areas some genuine choice at last, because “commercially viable” to BT means “where there is a competitor taking away customers who should rightfully be ours”, so that’s where it might be deployed – that and a few business parks with alt-nets – the notion that there will be any wide scale rollout of this is laughable.

    3. FibreFred says:

      300Mbps is 15 years too late?


      We can continue to have the same conversations forever but… it has been said many times… BT wanted to go the fibre route years ago.. Maggie put a stop to it, so.. rather than being unprepared it was more like “locked out”

    4. TheManStan says:

      Cable technology is apples and pears, cable is contended along the shared connection to households and, VDSL and Gfast is point to point contended on the backhaul.

      It would only need to be incremental rollout. BT retails current domestic Fibre product is 330 Mbps, so would only need to be that in the first phase.

      So to achieve that comfortably they would likely need a node within 200-250M of a property. Which would mean a node at ~400-500M, assuming they use the cabinet too. Then it all depends on the shape of cabinet service area, which with 50% of people being within 400M of a cabinet would mean the reach would be 600-750M, so for a cabinet in the middle of a small estate (never is always at the entrance) of ~600M diameter would be 6-8 nodes. Most of the hardwork is already done with the fibre feed to the VDSL cabinet.

      Phase 2 would be droppping nodes in at closer intervals as the market required it.

    5. FibreFred says:

      Just to pick up on your point about the nodes within 150m, I’m not sure how many we are going to see of those no, isn’t what they are testing G.Fast in the cabinet, it seems so?

    6. Carl says:

      No, they are testing FTTdp, too.

    7. Carl says:

      Yes I do believe it’s more than a trophy technology. It is a waste of time as a trophy technology.

      It’s cheaper and faster to deploy than FTTP which is why a number of telcos are working on it.

      Swisscom come to mind immediately. Think your bitterness biases you.

    8. TheManStan says:

      So why are Swisscom (whom you tout as FTTP only) playing with G.Fast if it’s a waste of time?


    9. Carl says:

      10/10 for passion.
      10/10 for Google.
      0/10 for comprehension.

      Try reading what you’re responding to before you type.

    10. themanstan says:

      Generous giving me 0/10…

      Miscomprehension on an epic scale… actually incomprehension…

    11. Carl says:

      I’m far too much of a pedant to allow myself to give negatives out of 10 🙁

    12. DTMark says:

      I’m not sure what “bitterness” has to do with it.

      I just find the idea that BT, having finally dragged fibre to cabinets about 15 years too late, are going to now drag fibre deeper into the network on a “commercial” basis, absolutely hilarious and pie in the sky.

    13. TheManStan says:

      How can it be 15 years late if they were not able to enter the domestic fibre market until 2007?

    14. FibreFred says:

      So DTMark,

      You find dragging fibre deeper into the network pie in the sky, never mind they’ve already done a huge drag already , the majority of which was self funded.

      Very odd 🙂

      Anyway for the majority they aren’t talking about dragging fibre any further are they, its about standing up G.Fast at the cab where distance to the premise from the cab is short enough

    15. GNewton says:

      @Themanstan: “How can it be 15 years late if they were not able to enter the domestic fibre market until 2007?” What are your sources or links for this? Were they really not allowed to do FTTP before 2007?

    16. themanstan says:

      Actually off by 2 years… 2009 change to BT´s Undertakings by OFCOM for FTTC and 2010 for FTTP.

      From: FTTC variation
      “2.4 The variation allows Openreach to control and operate the electronic equipment in
      BT’s access network necessary to deliver super-fast broadband using FTTC. Prior to
      our agreement to this variation the Undertakings did not permit Openreach to control
      and operate such equipment.”
      From: FTTP variation
      “2.4 The variation allows Openreach to control and operate the electronic equipment in
      BT‟s access network necessary to deliver super-fast broadband using FTTP. The
      Undertakings already allow Openreach to control and operate the electronic
      equipment in BT‟s access network necessary to deliver super-fast broadband using
      fibre-to-the-cabinet (“FTTC”) technology.”

      before that BTcould only run small trials.

    17. GNewton says:

      @Themanstan: Thank you for the links. This shows that Ofcom and the then government were quite incompetent, no surprise here. The UK is quite a backwards place.

    18. FibreFred says:

      It wasn’t the then government or Ofcom it was Thatcher that locked BT out long ago, Ofcom didn’t even exist then

    19. MikeW says:

      When Thatcher locked BT out of the fibre/TV market, people thought that was progressive, not backwards. At the time, I’d have been playing with a 1200/75 modem, and learning about X.25 for leased lines. Data didn’t seem terribly important for domestic lines then.

      Even when I first used the internet in 1991, before www, no-one really saw it as a mass market communication tool.

      For me, I want data, not TV. For the majority, however, it has long been the other way around … and from that perspective, the UK people are backwards. The government and Ofcom merely reflect the desires of the people … so it ends up no surprise that BT’s biggest competitors are TV distributors for whom data is a tack-on extra.

      In the first decade of this century, Ofcom reflected this principle: broadband was a cheap add-on, to be made as cheap as possible.

      It is only in the last 5 years that government has started to realise that our data capability has become a strategic economic asset. That our networks need growth and investment, and that we need to change our regulatory perspective of the access network being a staid century-old unchanging beast.

    20. themanstan says:

      For all BTs failings, not having FTTP infrastructure cannot be laid at BT´s door. European counterparts have not had this very onerous restriction and have been building for years.
      What is really bad is all the other ISPs could have taken advantage of this restriction, but did absolutely nothing… there could have been real competition…pity

  4. cyclope says:

    Why are BT going on about introducing higher speeds when their network is already capacity related having issues, all very well having a connection syncing at 300mnps or higher , but can the BT network cope i don’t think i can

    1. Carl says:

      Presumably because capacity issues on the BT Wholesale network aren’t Openreach’s problem and this is an Openreach project.

    2. Steve Jones says:

      I have never detected any contention on my 59mbps (line speed) FTTC link. Of course that doesn’t meant there aren’t places where this is under stress, but in about 18 months it’s never affected me.

      In any event, GEA/FTTC is used by several ISPs, several of which have their own back-haul (nobody has suggested there has ever been an issue with bandwidth from the cabinet to the hand-over point). I imagine the same will be true of any GEA/g.fast service.

    3. Carl says:

      Twice on the SVLAN, once on the metro node and once on the core in the space of the last 18 months in my case.

  5. adslmax Real says:

    If FTTC is connection higher than 80/20 then it more likely they will get 300/140 easily on G.Fast

    1. JamesM says:

      12 even!

  6. Darren says:

    The upload while a big improvement over FTTC is still a bit week, especially for a best case example. I’m nervous that could be much lower for most people.

    Downstream looks much better but I’m nervous, I’d hope they were looking to push out to DPs rather than just install in cabinets. Our 300M D-Side is 270M of aluminium up to the DP and then a 30M copper Lead-In. Most of the 600 properties on the cab are >300M aswell with lots nearer 1200M. GFast to the DP rather than the cab would be essential around here.

    I also hope that FoD is offered at a sane price for those that want it once the fibre is at the DP.

    1. MikeW says:

      You realise that BT can choose the split between upstream and downstream freely?

  7. Cammy says:

    Is this 300Mb figure actual download speed or a combined download and upload speed which BT now seem to quoting?

    1. MikeW says:

      Because the split between upstream and downstream bandwidth can be chosen anywhere between 90:10 and 10:90, the speed quoted for G.fast capability tends to be the aggregate.

    2. Cammy says:

      🙁 awww that is a little disappointing

    3. Carl says:

      It’s for download. They are actually testing 330Mb in the trials.

    4. Cammy says:

      Isn’t the 330Mb product FTTPoD or FTTP? I thought this was G.Fast with 500Mb (or 1000Mb max if you combine the up and down figures). Different product.

    5. Carl says:

      No? Never any intention to test G.fast at 500Mb initially. That’s an aspirational figure to reach at some point in the future.

    6. MikeW says:

      Interesting. Inside info on the makeup of the trials?

      I’ve not seen anything leak into the public domain as yet…

    7. FibreFred says:

      Surely a trial would be testing to see how fast it can go in certain set-ups rather than setting a speed

    8. Cammy says:

      “Surely a trial would be testing to see how fast it can go in certain set-ups rather than setting a speed”

      Agreed Fred, i do not know where he got the idea G.Fast is a 330Mb product, it has already been proven it can go faster than that albeit over short distances. I think with the 330Mb he is confusing it with a FTT(P) type product. G.Fast clear is capable of more, how much more for any final product will come down to how many G.Fast cabinets/point/units are rolled out and the distance the furthest home from one ends up being. 330Mb though in no way should be its max.

    9. FibreFred says:

      Its not just the amount of cabs/units/dp’s etc G.Fast is in its infancy I’m sure there’s loads than can be done with it to make improvements

    10. MikeW says:

      One of the restrictions BT is likely to face, at least initially, is that G.fast has been seen as a 100m product, which limits the number of lines that a node needs to support – likely to be around 16-32.

      The recent statements from BT – that the range is so much better than expected – is exactly what BT said at LightReading’s BTE: A game-changer. It means they can deploy fewer nodes at longer range; some will be at the existing cabinet (easy power), while others may now be in range of forward-power from a pillar at the existing cabinet.

      But those nodes probably now need to support 64-128 properties … which is probably larger than the system vendors were expecting – and it might bring in power and heat issues.

      Personally, I’d say that the power, heat and size parameters are *probably* the ones they’re really trying to trial over the summer – the things that matter as you scale up deployment – while also trying to ensure that the speeds they already know about are maintained.

      The deployed speeds will almost certainly come down to a trade-off of range vs power.

  8. fastman says:

    DT mark you seem to have forgotten the 45,000 + cabinets that were covered under the commercial programme announced long before the BDUk bidding process began

    1. FibreFred says:

      Quite a bit area to forget about 🙂

    2. DTMark says:

      I simply don’t accept that the two things are separate.

    3. FibreFred says:

      How can it not be? The commercial rollout was well underway before BDUK was even dreamt up?

    4. New_Londoner says:

      IIRC the FTTC deployments began part-way through the last Labour government, whereas BDUK was launched two years (?) into the Coalition government. How can these not be separate?

    5. Cammy says:

      “…whereas BDUK was launched two years (?) into the Coalition government.”

      “On Monday 6 December 2010, Jeremy Hunt and Ed Vaizey launched the Government’s National Broadband Strategy: “Britain’s Superfast Broadband Future”.”
      Thats only about six months after the coalition government not 2 years.

      First commercial FTTC went live end of Feb 2010/beginning of March.

      Labour based on those dates and your political affiliations either had nothing to do with with either or everything to do with both. So not very separate as it was all happening around the time just before and after the elections.

    6. Steve Jones says:

      I think “launched” was probably the wrong word. It was certainly announced in 2010, but by the time that the whole rigmarole of setting up the project, defining the framework, getting EU approval,issuing ITTs, evaluating responses and setting in place contracts were done, it was a good two years into the government’s term before any the deployment (including detailed designs) could actually start.

      The commercial roll-out had, in itself, started later than necessary as Ofcom prevaricated over their regulatory approach.

    7. FibreFred says:

      Exactly… it was at least another 2 yrs before anything got won on BDUK never mind started to rollout

    8. New_Londoner says:

      To clarify, when I said “launched”, I was referring to the point when the government had received state aid approval for the BDUK programme and was able to translate rhetoric into action. I think this wadroughly two years after the election.

    9. MikeW says:

      A reminder about key dates…

      In March 2009, BT had already started trials, and had plans to reach 40% by 2012, when Ofcom gave them regulatory freedom to deploy. In May 2010, they announced expansion to 66% by 2015.

      Around this time, the coalition took office and started a review of Labour’s plans that culminated in BDUK as we know it today. People knew there’d be intervention, but not how it would take shape.

      In Oct 2011, BT changed their end date to 2014. Later, in Nov 2012 this was brought forward again to Spring 2014.

      In June 2012, DCMS signed the BDUK framework with BT and Fujitsu.

      In July 2012, North Yorkshire became the first BDUK project to sign with BT, but they didn’t use the framework. As a pilot, they had their own EU approval.

      Note: this is the first point that BT knew they had won any work under BDUK. The government’s plans might have been known 2 years earlier, but no one knew who’d win; there was distinct competition around at this time.

      In Nov 2012, the EU approved the BDUK framework.

      In December 2012, the first BDUK cabinet went live, also in North Yorkshire, in Ainderby Steeple.

      In March 2013, Fujitsu withdrew from the BDUK tendering process.

      In May 2013, the halfway point was reached in BDUK contracts having been signed.

    10. Cammy says:

      The first BDUK contracts were awarded in Spring 2011. This is a lot less than 2 years after the first rolled out cabinets. Trials do not even enter the equation. Those that were done towards the end of the Labour government and the claims BT made at the time have little to do with the actual rolled out product we have today, which incidentally is now not due to be complete until around 2017. With G.Fast currently aimed for a 2016/2017 roll out, which will also probably slip a year or 2 if history says anything.

  9. GNewton says:

    @MikeW: “Note: this is the first point that BT knew they had won any work under BDUK. The government’s plans might have been known 2 years earlier, but no one knew who’d win; there was distinct competition around at this time.”

    What competition exactly was there back then, other than Fuji pulling out early?

    1. MikeW says:

      In July 2012 (ie when the first contract to be awarded unconditionally was from North Yorkshire) Fujitsu was the obvious contender for framework projects … and they hadn’t dropped out at that point. BT was having to respond to tenders with prices good enough to get the business … and that counts as competition.

      However, North Yorkshire was a pilot scheme, didn’t follow the framework, gave commercial providers more freedom to come up with schemes (including one where NY owned the network, similar, I guess, to SYDR), and could pull in more tenders.

      According to a mid-project evaluation in 2013, SFNY originally had 6 bidders. That came down to BT and Fujitsu in the final round. From talking to the guys running the tender on the council side, I know BT had to work at getting that contract.

      I know it doesn’t fit the rhetoric that some people have around here, but there certainly was competition at the time, and it did constrain BT’s bids.

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