Fifield gets serious about VDSL cross-talk issue


news Communications Minister Mitch Fifield has registered a new regulation which will force Australia’s broadband industry to develop its own industry code dealing with the thorny issue of cross-talk interference in the new generation of Fibre to the Node and Basement technologies.

Under Labor’s previous National Broadband Network model, optic fibre cable would have been deployed to most Australian premises. However, the Coalition’s Multi-Technology Mix model re-uses Telstra’s existing copper network with technologies such as the VDSL2+ standard for many Australian premises, in the Fibre to the Node and Fibre to the Basement models.

One of the issues for these types of technologies is that interference between cables may exist where multiple operators have deployed their copper cables into buildings. This is already proving to be an issue in many apartment blocks in metropolitan areas, due to the fact that companies such as TPG and OPENetworks are deploying FTTB infrastructure in competition with the NBN company itself.

In July, then-Communications Minister Malcolm Turnbull published the draft version of a regulation to deal with the issue.

The Telecommunications Amendment (Next-Generation Broadband Interference Management) Regulation 2015 inserts a new regulation into the Telecommunications Regulations 2001 legislation, which enables a body or industry association representing the telecommunications industry, to develop an industry code that is enforceable by the Australian Communications Media Authority (ACMA); or if industry cannot agree to a code or the ACMA refuses to register the code, the ACMA to make an industry standard.

The Department of Communications has not yet published industry responses to the initial consultation with relation to the regulation. However, it is believed that the industry association and self-regulatory group the Communications Alliance is already working on an industry code dealing with the cross-talk issue.

As first reported by iTnews, yesterday Senator Fifield published the final version of the new regulation.

In its submission to the Vertigan Review earlier this year, the Communications Alliance already highlighted interference issues that could impact on the performance of VDSL2 services provided over a single cable bundle.

In the explanatory notes to the regulation, the Government noted that the issue was already a live one. “Such systems are now being rolled out in cities by providers such as NBN Co, LBN Co, OPENetworks, TPG and iiNet, and there are anecdotal reports of interference between the new and legacy telephony and DSL systems,” the document stated.

The issue is set to become exacerbated due to the fact that the NBN company is planning to substantially overbuild a number of existing FTTB and FTTN networks.

In mid-October, for example, the company revealed it planned to overbuild TransACT’s long-established Fibre to the Node network in the ACT, which covers most of Canberra.

How serious is the cross-talk issue in Australia? I’m not sure yet. I would welcome hearing from anyone who has further information on how it is affecting broadband customers at the moment, and how big a problem they expect it to become in future as the NBN company continues to deploy copper-based broadband technology.

One additional interesting point is that I do not believe TPG — the NBN company’s main FTTB competitor — is currently a member of the Communications Alliance. One wonders how extensively Australia’s third-largest telco is being consulted in the development of this code.


  1. How much would this have cost the tax payers?

    And why only enforcing now? and not 10 years ago under John Howard, forcing the xDSL to comply?

    And Who will pay for the cost? Will it be User Pay? RSP Side? Tax Payers? or All 3 ?

    And why are we doing this, when we should be looking at XGPON 2 Network!

  2. You don’t get this problem with FTTP, or HFC, or LTE or Satellite.

    Basically xDSL technologies have served us well but are getting to their limits when set against increasing demands and expectations. The juggling act just becomes ever more precarious.

    In the end we will all pay for the increased complexity and effort required to coax these systems to deliver not to mention the lost opportunity cost.

  3. Why in the hell are they rolling out FttB in apartments that already have FttB in the first place when they could rollout access to people who have little or no access.


    • This is what the government NBN should have been limited to, in my opinion – only those places that have no existing broadband. Blackspots and the fringe. Let the private sector bear the cost of infrastructure where they are already, because it was demonstrated that they can. That would be “stopping the waste.”

      • Because Telstra has been so great at actually upgrading infrastructure over the past 15 years right?

        Since ADSL2 debuted, very little has happened to advance the quality of broadband access for Australians on copper.

        Telstra didn’t care, they did the bare minimum to keep it working for telephones, and focused on their much higher profit margin mobile network.

        • Remember, Telstra didn’t even go to ADSL2 until well after Internode and iiNet, and they artificially limited ADSL1 to 1.5mbps for years. I remember a conference where the major network vendors were spruiking the ability of their modems to support up to 24mbps ADSL 2+, and I asked them where, exactly, in Australia could such a device be used that could take advantage of anything greater than 1.5mbps, and they had no answer other than mumblings about evolving standards. I suggested they do what they could to push Telstra on better services so there would actually be demand for their products. It took two years before I saw ADSL2+ from iiNet, and Telstra took another two or three years to catch up in most suburbs I had the misfortune to have to deal with.

        • That’s only because there was no physical competition to Telstra over almost all of Australia, so there was no incentive to upgrade. (No physical competition because of Telstra, by the way.)

          If either major party had a clue, they would incentivise companies to build/upgrade networks and leave the NBN for the commercially unviable areas.

          This practice of a blanket NBN overbuilding everyone is ludicrous. I actually thought the Coalition knew better. But they don’t.

          • Is it likely that Private companies would compete on infrastucture? Or would we end up with a patchwork of mini-Monopolies, or even more likely Tesltra owned monopoly Infrastructure everywhere except a few pockets where Telstra have overbuilt and then price crushed the competition until they go bankrupt a-la OptusVision?

            Even if there was Infrastructure competition, would the prices be as low as a single Government Infrastructure Provider can make it?

          • @Martin H
            Scroll down to read Brendan B’s explanation of crosstalk affecting VDSL when signalling isn’t being managed by a single operator. Basically, if you don’t have a single operator, you have crosstalk (because crosstalk is inevitable, the only way to eliminate it as a problem without replacing the cable is to control signalling down adjacent pairs so the signals are timed in such a way that the equipment can predict crosstalk and filter it). And that crosstalk is crippling.

            So, just in case you don’t understand the ramifications of what that means, it is this – in order to run a VDSL2 FTTN network the standard (the engineering) requires that the entire network has a single operator. That is a scientific, physical constraint.

          • @Stevo

            You only need to look at America to see a real-world, existing example of how infrastructure competition actually works. First past the post wins, and very little actual competition is ever offered, because the cost of a second operator entering an area is the same as the first, but they have to accept that they can only gain customers by dislodging those from the original, meaning they will have to fight tooth and nail for every tiny but of market share. But the original operator just had everyone flocking to them. There’s no point unless you have such a compelling competitive advantage that you know everyone is going to switch the moment you finish your deployment (such as replacing copper with fibre, particularly synchronous fibre like Google are deploying).

            So yes, you end up with little monopoly ghettos. Exactly as predicted back in April 2013 when this retrograde, idiotic policy was first announced.

          • Thank you for your replies. My intention was to get that particular idea out there. Different ideas must be explored, other than the left-wing ubiquitous network vs. right-wing free market mindset. I like to think that we have progressed as a nation past the ideology of the two camps, ideology that is damaging in the context of a changing world.

  4. I have no knowledge of the Australian situation, but in the UK crosstalk is a major problem and a fact of life. The FTTN deployment has made it almost a household word, according to news articles. It’s dropping people’s speeds by tens of Mbps in some cases.

  5. Sounds like a pre-emptive strike to ensure nbn can just barge through any issue it encounters.. or perhaps I’m just all too negative/suspicious of the entire gov/nbn nowadays… .

  6. It would be hard to judge without Telstra opening the “Vault of Copper Secrets” but it would be significant.

    Over the years I have seen qualifications for lines into business premises come back as “too far from exchange”, yet another line to the same MDF/IDF frame – (and therefore in most instances, the same bundle of cable) – come back as fine. Given the exchange and the distance from the exchange are the same, the difference can only be down to the condition of individual lines.

    You can bet that many of these are due to crosstalk or other line faults, which are going to start coming out of the woodwork as FTTN is rolled out. You’ll hear about it all the time in the coming years, and the folly of sticking with the existing copper will be plain to see.

  7. Renai, this issue was predicted in 2013 when the LNP released their NBN counter-plan. VDSL2 needs a good quality copper line without interference. It cannot operate with other standards like ADSL on adjacent lines. At ‘extended’ ranges of greater than around 500 to 700m (depending on copper quality and a range of issues) ADSL2+ provides superior performance.

    Crosstalk is a very well understood phenomenon. It is why one of the primary differences between twisted pair cable standards is simply upgrading in shielding and isolation – the actual copper in CAT8 is essentially the same as CAT6, but the shielding is vastly improved, allowing up to 40gbps transmission. The key to high performance is utilisation of the widest possible frequency spectrum at the shortest signal rate. Crosstalk interferes with the data, making it unreliable. If you can’t eliminate crosstalk and interference from radio waves, you need to exclude affected frequencies, so you can’t utilise them. If you want to improve performance, you need to use those frequencies, so eliminate interference. Because you can’t change the physical characteristics of the cable, you need to remove the environmental sources of interference. We can’t eliminate radio waves, so we still have to design around that, but we can control crosstalk, through tight signalling control. As long as we control every bit of electricity (signal) travelling down every piece of adjacent cable. If you can’t control that, you can’t eliminate crosstalk, so VDSL2 won’t work properly. Even when you think it’s ‘ok’, the reality is that sustained activity on the adjacent line you’re not controlling means crosstalk will decimate your VDSL signal quality. That’s why NBN are defining their minimum quality standard as only capable of certain performance for 1 second – it’s a complete #@&$ing joke because if there’s potential for crosstalk, your lovely new NBN service could actually be unusable frequently. You’d be wishing you were back on ADSL in that case.

    I can’t believe we’re at the point where the government is trying to address an issue they’ve been avoiding for years and even Delimiter is wondering how much impact it might have. Here’s your take-home – crippling. Crosstalk can cripple FTTN. It might only be a sporadic problem for some, making it hard to quantify or prove, but you have a neighbour running bittorrent over an interfering standard and you can kiss your FTTN Internet goodbye.

    The only way NBN can avoid acknowledging that it is crippling is to engage in misinformation and avoidance, forcing people to provide anecdotal evidence of the issue, then sending techs to test the line under ‘usual’ circumstances. Which is utterly unscientific – if they want to test the issue, they need to inject interfering signals into adjacent lines and test performance. Yet that’s not necessary, because the actual STANDARD already tells us, because it was engineered to account for this problem in the first place. It is crippling. That’s why you can’t run VDSL2 services over lines where other standards will operate adjacently. In fact, I believe they may actually be in violation of the standard. Which would mean they’re no longer running a legitimate VDSL2 certified network. Now wouldn’t that be interesting…

  8. Would there be crosstalk from other lines running VDSL or only from other signals such as ADSL.

    • Both – isn’t obsolete copper wonderful?

      PS. VDSL crosstalk improves when they turn on Vectoring – but they cant do this until all lines in the bundle are VDSL2+.

  9. “How serious is the cross-talk issue in Australia? I’m not sure yet.”

    Huge. Services running Annex M, an extension of ADSL2+ are increasingly port constrained to meet deployment classes, as ADSL reaches saturation.

    VDSL2 is even more susceptible to, and more inclined to affect ADSL Annex A. So until a number of pairs are managed, the range and speeds are severely impacted.

    Vectoring seeks to partly mitigate this by bundling a number of pairs to ‘manage’ the line characteristics for each copper pair. This allows services to operate at much higher speeds, over a longer distance, and is crucial to reliable and fast FTTN operation; this only really works well when the systems use are able to control practically all the pairs in use.

    That there is direct infrastructure competition, means vectoring is less effective. That’s right, folks; the ACCC wants to see a competition model that automatically reduces the performance of each network because of infrastructure fracturing.

    Insert ‘sad trombone’ meme, here.

    Between the ACCC’s woeful lack of understanding of what the hell it is doing, and a government hell bent on deploying a model first, before any regulations pertaining to it’s deployment are even tabled, you can’t help but laugh.

    It really is that stupidly funny.

  10. I never wanted the MTM to be bad but I’m getting a really sick feeling in the pit of my stomach that the MTM Bus is about to drive off a cliff and the passengers are all Australia.

    • When they got elected i was worried about this – i wasnt hopeful but given the RGR madness i thought, give them a chance. “self, give them a little time. its possible it wont be all bad”. well … i did say possible….

      cos not long before the 6 month mark of this government ive had that sick feeling, and its gotten worse with every jolt of th barely driven and wandering MTM bus….

      i dont think we’ve reached Cliff yet however; that i suspect is the next election. if the MTM is still in operation past that (read LNP win), then we are over and flying. it will be all downhill from there…..this is really the most asinine policy and even worse the non-techie inclined population – read nearly all of them – wont have a clue whats happening and are likely to misunderstand the root of the problem and blame the wrong folk for the mess. and at this stage it really is a big, burgeoning mess.

      given the average aussie voting public though; and the ascension of King Mal (yes i know hes republican) i think the chances are very good we are stuck with this mess until someone with some testicular fortitude and nous goes “wtf is this mess?” and fixes it.

      if it helps anyone considering that job, you will have an instant rusted on here?

  11. It’s so reassuring to know that Turnbull and co put us on this path to vectored ADSL2 without the slightest idea of how to achieve it.

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