Br0kenTeleph0n3

Following the broadband money

Bell Labs turns copper to gold – not

with 9 comments

Bell Labs, which more or less invented the communications network business, has just given a new lease of life to copper network. In theory.

Its researchers have achieved speeds of 10Gbps over a pair of twisted copper lines in the lab. They have also got them to deliver 1Gbps symmetrical broadband, again in the lab.

That sounds like BT (in fact pretty much all incumbent telcos) is justified in pursuing its fully-depreciated investment in copper wires instead of switching to cheaper to operate fibre.

But the good engineers at Bell Labs also published a number of caveats.This is short distance technology. “The XG-FAST technology can deliver 1Gbps symmetrical services over 70m (for the cable being tested). This was achieved using a frequency range of 350MHz. Signals at higher frequencies were completely attenuated after 70m.”

So that’s it; 70m is the distance limit for gigabit copper.

But there’s more. “In practical situations, other significant factors that can influence actual speeds (not taken into account during these tests but which have been studied extensively elsewhere) include the quality and thickness of the copper cable and cross-talk between adjacent cables (which can be removed by vectoring),” they say.

They also published this handy guide for operators who are trying to match the exponentiating demand for bandwidth against their budgets for switching to fibre. It makes a trenchant leave-behind when you discuss the provision of high speed broadband with your local councillors and MPs as we approach the upcoming elections.

During testing, Bell Labs showed that

Technology comparison

Technology

Frequency

Maximum aggregate speed

Maximum Distance

VDSL2*

17MHz

150Mbps

400m

G.fast phase 1*

106MHz

700Mbps

100m

G.fast phase 2*

212MHz

1.25Gbps

70m

Bell Labs XG-FAST**

350MHz

2Gbps (1Gbps symmetrical)

70m

Bell Labs XG-FAST with bonding***

500MHz

10Gbps (two pairs)

30m

* Industry standard specifications. G.fast allows for upload and download speeds to be configured by the operator.

** In a laboratory, reproducing real-world conditions of distance and copper quality.

*** Laboratory conditions.

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Written by Br0kenTeleph0n3

2014/07/10 at 10:43

9 Responses

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  1. Most councilors in rural areas would struggle to articulate the difference between copper and fiber beyond one is shiny metal, the other is glass, even more so in the context of performance delivered to punters^D^D^D^D voters.

    I understand 2nd hand the gentleman mentioned is a good councilor in the general sense http://ruraldebugging.blogspot.co.uk/2013/12/broadband-in-ceredigion-are-we-in-good.html but for broadband you see my point that any takeaway other than pizza is probably a step too far.

    Clive King

    2014/07/10 at 11:05

    • I think (hope) you may be underestimating our noble councillors’ familiarity with broadband media. But if what you say is true, we need to educate them by asking them awkward questions in public forums. None can bear public humiliation, so if they won’t get to grips voluntarily, we need to shame them into it. I admit it hasn’t worked so far, but these are early days. Water wears away the hardest stone in time.

      Br0kenTeleph0n3

      2014/07/10 at 11:50

      • I fully agree with the sentiment and there are a number of good councilors in our local area (I can’t speak to other areas), but most just nod and don’t really get it. Worse, they can’t scrutinize council policy themselves and have no mechanism to bring people with the skills in to help them. The problem with public humiliation is that you then get excluded and branded a trouble makers (Can you think of an other welsh resident who might be have suffered this fate?). Until we have a consumer lead organization as militant and influential as the NRA (a bit extreme I know, but you get the point) this fun will continue.

        Clive King

        2014/07/10 at 11:59

      • Funnily enough I can think of another Welshman who may well have galvanised the Welsh auditors to take a look at what you are getting for the £425m Superfast Cymru, apart from (possibly) overbuilding the £30m taxpayer funded FibreSpeed network, which has been mysteriously prevented from providing adequate service to all those that asked for it. I note your call to arms. I trust the militancy will be non-weaponised, though with feelings running this high…

        Br0kenTeleph0n3

        2014/07/10 at 12:07

      • Only a sharp wit which is unlikely to prevent the last 4% being offered subsidized satellite as an alternative.

        Clive King

        2014/07/10 at 12:21

      • A sharp wit and a thick skin is probably all you need 😉

        Br0kenTeleph0n3

        2014/07/10 at 14:51

    • Gentlemen,
      I suggest most councillors, who do not suffer themselves, will have accepted the entirely false statement that “Fibre Broadband” is already delivered via BT Wholesale “giving access” to astronomic user-numbers far beyond the maximum cabinet capacities; as well as the similar marketing – speak from Virgin Media.
      It is also important to realise that the public servants within BDUK and LAs are deeply involved.
      We wrote the Surrey county council in 2011
      http://www.texp.co.uk/downloads/SCC%20submission%20Iss%202.pdf
      with the front cover words including:-

      “An analysis of the likely population coverage of
      private sector Broadband deployment plans &
      the potential danger to SCC’s Broadband project
      if these are misunderstood …….

      3. Therefore the SCC project must deliver adequate Broadband to far
      more premises than originally envisaged; consequently the project is in
      danger of failure before it has even begun.

      walterwillcox

      2014/07/10 at 15:46

  2. Its a superfarce.

    cyberdoyle

    2014/07/11 at 23:17

  3. This reminds me of BT labs back in the 80’s/90’s and some of the stuff they came out with…

    Good news is that with those figures we don’t need to worry about deploying optical paths any more we can just use the existing shonky copper/ally lines and bond them up. I’m nothing against getting the best of of what’s there – but come-on there is only so much flogging a dead horse you can do especially when BT don’t do any maintanance on there line plant any more…

    How many of you on big/EO sites still get air sent up your main cables?! Lol

    Q

    2014/07/15 at 17:04


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