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ASDL2+ from street cabinets to solve 2 Mbps USC
Sunday 05 October 2014 15:09:56 by Andrew Ferguson

The Universal Service Commitment is something that to date appears to have been woefully neglected and the small percentage of people who have seen their cabinet enabled for VDSL2 but are too far from it to get any speed benefit have been left wondering what chance there is for improved speeds. A product description for the GEA-FTTC service that Openreach publish for communication providers and has just been updated has a lifeline for those who live a long way from their street cabinet and telephone exchange.

It appears that ADSL2+ with appropriate power masking may be deployed from the Openreach street cabinets alongside the existing VDSL2 services. Indications are that a maximum speed of 12 Mbps download (1.4 Mbps upload) would be used, and this should benefit those who are more than 2 km from the cabinet. VDSL2 should provider 24 Mbps or faster at a line length of 1km, but speeds drop away fairly quickly after that, while ADSL2+ will generally manage 6 to 8 Mbps over lines as long as 3.5km and should keep running all the way to 5.5km at speeds above 2 Mbps.

No indications on timescales or pricing, but with testing and specifications being outlined it is just a matter of time for more information to become available.

The price issue will be interesting as there are those who want a bit more speed, but do not want to pay the full £10 to £15 premium that VDSL2 commands, particularly when it might only deliver speeds in the 5 to 10 Mbps region, so a lower price point would be welcomed. The service looks to be presented as a GEA-ADSL2+ service, so in theory any provider utilising the GEA platform would be able to make use of the product.

Deploying ADSL2+ in this manner would be simpler if exchange based ADSL2+ was to cease operating, but we are some years away from that happening due to the popularity of LLU in the UK, but the power masking should ensure that the impact on existing services is minimal. It is believed that some 2% of cabinet based lines are longer than 1500 metres and thus in the prime zone to benefit from ADSL2+ delivered this way.


Posted by fabrettitd over 2 years ago
I like this idea. I think that's sweet :)
Posted by Blackmamba over 2 years ago
Hi Broadband Watchers
The unit has been tested 2000 metres 3000 from the FTTC so that will get over the 15 megs download target (99.7%) in Surrey.
Posted by TheEulerID over 2 years ago
I would have thought that on non-LLU exchanges, it ought to be possible to get rid of exchange-based ADSL for any lines connected through an enabled cabinet. It would have to be done at the normal wholesale cost of exchange-based ADSL of course, but surely everybody would benefit.

I would also have thought any cabinet-based ADSL would still adversely affect exchange based ADSL going via that cabinet, no matter how the power masking is done.
Posted by TheEulerID over 2 years ago
On comments on another news story I suggested the idea of using cabinet-based VDSL with different, longer reach power plans where there was no LLU. All users would be moved to VDSL and suitably capped services would be offered at equivalent ADSL wholesale prices. (Of course this would mean new consumer modems).

nb. the logic would be to eliminate exchange based DSL wherever there are enabled cabinets. However LLU has painted the industry into a corner...
Posted by WWWombat over 2 years ago
Fortunately I do more than watch broadband. I understand it too...

If you read the spec, you'll see that it runs with a line profile for a maximum download speed of 12Mbps.

That makes it unlikely to do as you say, helping towards Surrey's 15Mbps target.

It will, however, help reach the 2Mbps target for the USC component of other counties. North Yorkshire should be completing their phase 1 project this month ... and this could/should help provide more certainty of coverage at longer range.
Posted by WWWombat over 2 years ago
Whether this idea really proves to be useful depends almost entirely on how much it is affected by the ANFP power masks for the cabinet.

The set of frequencies that get masked (reduced in power) depends on the distance from exchange to cabinet; where the cabinet is a long distance out, the highest frequencies of the exchange-modems will have already attenuated away, allowing the cabinet-based modems to re-use them, and use them at higher power.

I suspect this will end up only being useful for cabinets with CAL values of 30, 40 or 50 (ie the more distant cabinets).
Posted by TheEulerID over 2 years ago
If all lines going via an activated cabinet were serviced from that cabinet, then I see no reason why the exchange-based power mask couldn't be used.
It's that co-existence of exchange and cabinet-based services which are the problem. However, the best technical use of the network is not possible as its embedded in a morass of conflicting interests controlled by a quango.
Posted by Gadget over 2 years ago
@TheEulerID - what happens to LLU operators who do not want to shift to a VULA-type service or have only just recently invested in MSAN?
Posted by WWWombat over 2 years ago
New Zealand solved this by allowing exchange-based LLU to be forbidden once a cabinet was installed, for that part of the coverage area, and requiring all connections to be made out at the cabinet.

Of course, they started down that path with ADSL2+ cabinets, even before VDSL2 was around.
Posted by TheEulerID over 2 years ago

That is, of course, the problem which I refer to. In effect the technical standards for what is, after all, a privately owned network are controlled by a quango. Protecting the interests of LLU operators prevents the network being used in the most technically efficient manner.
Posted by JNeuhoff over 2 years ago
Why not using VDSL rings for overcoming line distance issues? ( or

Also, what's wrong with using fibre?
Posted by dogbark over 2 years ago
Headline says "ASDL"
Seriously :)
Posted by generallee94 over 2 years ago
Posted by herdwick over 2 years ago
Do VDSL rings exist as a standard, do they comply with the ANFP ?

Cabinet based ADSL and exchanged based VDSL exist elsewhere and are covered by the relevant standard so this seems a sensible move. Once you've made the decision to have kerbside electronics you may as well maximise the use of them. What's next - voice from the cabinet ?
Posted by mdar5 over 2 years ago
Well yes, that is the next stage so that the cabinets become local exchanges and the various old exchange buildings can be closed down and sold off for housing.
The cabinets would then all be controlled from regional fibre head end exchanges.
Posted by Brunel over 2 years ago
Any solution/answer to EO lines?

Especially, >6Kms?
Posted by andrew (Favicon staff member) over 2 years ago
Copper regengineering
Fixed Wireless
Posted by WWWombat over 2 years ago
Voice from cabinet is a possibility, but it would increase the robustness/reliability/availability requirements on the MSAN there.

Currently, the DSLAM could fail entirely, and have no impact whatsoever on voice access to emergency services. Not sure the current batteries are a good enough solution for backup if a power outage is widespread.
Posted by godsell4 over 2 years ago
This would be good for Market1 exchanges where we have been extra for many years already.
Posted by adslmax over 2 years ago
BLASTED AT BT for CONNED capped at 12Meg for ADSL2+ from 24Meg on the FTTC cabinet. Disgraceful by BT.
Posted by Blackmamba over 2 years ago
Hi Broadband Watchers.
The above service off the FTTC gives an extra option to the ISP!s for a lower costing product on speed to the customers that they may (require request) in this Market Area this also transfers the service from the exchange.
Posted by AndrueC over 2 years ago
@adslmax: It's a little difficult to understand your post but the 12Mb/s cap seems to be in place to avoid radio interference with other services. If you are indeed complaining about the cap then I think you're being unreasonable blaming BT for the laws of physics.
Posted by Blackmamba over 2 years ago
Hi An.
It is Openreach who is providing the service to all ISP,s. on FTTC it is called an open market.
Posted by WWWombat over 2 years ago
Stop acting like chicken little. The world isn't falling in, and no-one is being conned.

1) ADSL delivered from the cabinet will be transmitted at lower power than we expect from an exchange.
2) To prevent interference, some frequencies will be transmitted at even lower power.
3) The service will be offered to people 2km from the cabinet.

All 3 factors result in speeds below the theoretical maximum of 24Mbps. Lines will probably be *lucky* to reach 12Mbps, rather than being capped.

Why don't you complain about the 80Mbps cap on VDSL2?
Posted by mikejp over 2 years ago
www - "3) The service will be offered to people 2km from the cabinet." - is this a stated min distance? Disappointing if so, since we have several here at less than that with poor VDSL.
Posted by adslmax over 2 years ago
VDSL2 should be uncapped speed, not limit to 80/20. Best to leave to the fastest speed at the highest sync rate whatever the distance from the fttc cabinet to the property. What the point of stupid capped 80/20 by BT OPenreach who are tight git with money.
Posted by AndrueC over 2 years ago
I'm guessing that 80/20 was chosen to avoid having a small minority on the upper speed. Knowing the ASA and Ofcom and general public react they would probably rather sell an up to 80/20 where a significant number can get 80/20 than an up to 'whatever' where only a small number get close to 'whatever'.

Frankly it's people like you that shout and love to have a go at BT that cause that kind of thinking. BT prefer to play safe than risk your wrath.
Posted by godsell4 over 2 years ago
So on a Market1 exchange, where we have been paying extra just to get ADSL1 whilst many have 'enjoyed' ADSL2+ for many years, will ADSL2+ be enabled by default on newly enabled FTTC cabinets? Is it implied that I may have to pay more *again* to an ISP just to get ADSL2+ let alone VDSL2. Is this all correct?
Posted by WWWombat over 2 years ago
@mikejp 1
Unknown, because all we have access to is the test specification that Openreach applies to consumer modems to check it will work in the network.

However, when testing like this, you'd expect the tests to examine the normal boundary cases. These tell us when BT expect the modems to be used.

In this case, they test ADSL performance at 2km, 2.5km and 3km.

In contrast, most of the old VDSL tests go up to 2km, while a few go up to 2.2km.
Posted by WWWombat over 2 years ago
@mikejp 2
To be precise, those tests are "2km with 0.5mm copper", and they're really testing with simulators and noise models that match copper of that gauge.

When it comes to real customers, with copper of a different gauge, or even a mix of gauges, or some aluminium thrown into the mix, plus a few less-than-perfect joints, we'll find that real life isn't so sweet.

Hopefully they'd deploy based on attenuation measurements rather than line length, which should take these factors into account. Or apply a "suck it & see" approach to installation.
Posted by andrew (Favicon staff member) over 2 years ago
@godsell4 Until pricing is announced by Openreach it is impossible to say, BT Wholesale might not decide to offer the service. It may be one of the LLU operators pushing for this as an option.

But I would expect to be paying more, but then 14 years ago 2 Mbps cost £40 to £50 per month.
Posted by WWWombat over 2 years ago
Unknown, for the same reasons mentioned to @mikejp, and the story correctly points out "No indications on timescales or pricing"
Posted by Blackmamba over 2 years ago
I feel the system will be used over the one mile distance 1760 yards this is where the pricing will kick in on all 3 Markets.
Posted by chilting over 2 years ago
If anyone from BT is reading this, can I suggest that you use West Chiltington to test out this ADSL2+ with power masking.
You have an exchange already on ADSL2+ and FTTC that has provided a good service to some of the village, you have customers on long lines with slow speeds on a mix of fibre, ADSL2+, ADSL1 and dial up plus you have some abysmal infrastructure. If it works here it will work anywhere!
Posted by Blackmamba over 2 years ago
Hi Chi
I am sure Openreach will provide this service as soon as ISPs and Customer are willing to market the product this will give a extra option on the CAB.
Posted by themanstan over 2 years ago
Will OR reserve space in a cab for them to meet BDUK obligations with this?
Posted by andrew (Favicon staff member) over 2 years ago
No guarantee people will order the service, hence why cabinets are never fully populated with cards at launch.

Subsequent card expansion and extra cabs is financed by Openreach. Should be no gap money as the demand level is proven.

BDUK could exist on 100% capacity from day 1 but am sure there would be cost implications of this.

Remember VFM rather is the big driver.
Posted by chilting over 2 years ago
It would be nice to have the choice.
That's all I ask for.
Posted by Blackmamba over 2 years ago
Hi Broadband Watchers.
Openreach will not provide this service untill after 80/40 meg down orders start to wain. I would have thought that most of the latter Cabs have the Equiptment available or it is cheap to modifie or it would not be cost effective.
Posted by tdw42 over 2 years ago
If this service were to be offered I imagine the install price would be close to or the same as FTTC self-install due to the extra work involved compared with exchange-based ADSL2+.
It appears that most existing ADSL2+ modems wouldn't work as the SIN calls for PPPoEoA or IPoEoA with 802.1Q VLANs, as used by GEA-FTTC, rather than the usual PPPoA.
It would be interesting to know if customers taking this service would count towards the commercial threshold, at which point BTOR pay back some of the BDUK funding, as the delivered service is below the 24Mb superfast threshold.
Posted by PaulVann over 2 years ago
Does anyone know what the approx cost of installing ADSL2+ in a cabinet is? And does it require power? This strikes me as a potentially really good solution for long distance premises.
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