broadband Engineer

Superfast Broadband: Pat on the Back for BT #FTTC

It’s fast moving this new web based world of ours. Some of it is faster moving than others.  This morning I woke up to the news (in the twitter stream – thanks to @ruskin147) that BT was looking to pull forward the rollout plans for “superfast” broadband. To do this the company is taking on an additional 520 engineers and bringing forward £300m of spend.

Competition is great. Clearly Virgin, with its 100Mbps service, is forcing the pace here. BT is saying that by 2014 it will be serving two thirds of the population with download speeds of 70 – 100Mbps.

I realise that I have occasionally been known to be a critic of those responsible for our national broadband infrastructure. On this occasion I’m going to hold back and say to BT:  Well done. This is a good decision. Keep it coming.

Fibre To The Cabinet or superfast broadband is the subject that arouses most interest on this blog.

BT says that six million premises (about 25% of the total) already have access to its fibre broadband technology which is currently an “up to 40Mbps” service for most people (upgrade due). Clearly not all 6 million premises have subscribed to the faster broadband or the average speeds reported by Akamai in their State of The Internet Report would be higher.

It’s worth drilling into this a bit more. A quick “back of a spreadsheet” calculation suggests that if the average broadband connection excluding FTTC was 5 Mbps (aka Akamai) and that if FTTC gave us an average of 25Mbps (which is I believe rightish) then if everyone who could get it subscribed to superfast broadband then the average UK internet download speed should increase to 10Mbps. These are very rough numbers but it would put UK plc at or near to the top of Akamai’s European league table as opposed to our current 16th position.

By the end of 2014 BT is saying that 66% of premises will get between 70 and 100Mbps. Lets say the average speeds were 50Mbps and that the remaining 34% get the 2Mbps touted by the government as the minimum target for everyone. If everyone who could get superfast broadband took the service then I see overall average speeds moving up to just under 34Mbps1. This doesn’t take Virgin subscribers into account. Virgin users will get average speeds near to those advertised and might push the overall averages up.

This all depends on a high degree (100% ?!)of uptake of the services but based on this research it will be interesting to see how the UK moves up the Akamai table. Before Her Majesty’s Government gets excited remember we are up against the likes of Finland who will have universal 100Mbps (and above) Fibre To The Premises and with FTTP you usually get the advertised speed.

That’s all.

PS I’m still waiting to hear a definition from HMG as to what constitutes “best superfast broadband network in Europe by 2015″. If anyone out there has any inside knowledge on this please let me know. I suspect we will have to wait until 2015 to find out.

1   Interesting to note that back in 2004 our first BT Central pipe – the backhaul connection for 800 broadband customers was a 34Mbps ATM line – the number I am now suggesting could be the average speed of a single broadband connection by 2015.

Trefor Davies

By Trefor Davies

Liver of life, father of four, CTO of, writer, poet,

15 replies on “Superfast Broadband: Pat on the Back for BT #FTTC”

I think its great that those near to a cabinet will get ‘up to 80meg’ next year, but I feel very sorry for the millions who won’t. I think the digital divide is opening even wider, and averages mean nothing to us rural people who will get fobbed off with expensive satellites or BET to get a miserable 2meg with hardly any upload. I think it is up to the government to make sure no public money goes into patching up the copper anywhere, and the digital switchover money goes into new rural fibre feeds where innovators can build them high speed fibre networks, which in turn will expand into cities, bringing true next generation access and some competition. Otherwise we will end up a third world country, stuck in the copper slow lane. 80meg may seem fast to us now, but look at your 2004 figures, and in another decade read this post again.

As ever the biggest barrier to true “mass” adoption isn’t just coverage but affordability. BTs biggest problem, and to a lesser extent Virgin Media’s too, is that superfast broadband attracts a price premium (be that the cost of an upgrade or the service itself).

This is all fair for an emerging service but ADSL didn’t really fly until TalkTalk , Tiscali, Orange and Sky etc. began offering budget priced solutions.

Now some ISPs have developed unrealistic expectations and to sell this new service they’ll need to do that again, at least until demand for higher quality content forces people, kicking and screaming, to move. Unfortunately those providers have no MPF equivalent (VULA doesn’t quite cut it) for FTTC so for now BT and sibling Plusnet have a lot of market control.

I think that BT are dreaming if they are going to not only achieve these results, but also on the speed of the fibre connections!

How on earth can 2/3 of the population get 70 – 100Mbps!??!? I live just over a mile from my exchange. I live in the Greater London area. I live in a highly developed area – there is hardly any undeveloped land around. Yet, I am still on BT copper, get 3Mbps down, have had 3 dates set for FTTC and still no sign of it, and if/when I do get it to only expect 27Mbps. I say ‘only’ as I am comparing this to their 70-100Mbps.
Thrown these kinds of figures around is a load of BS as BT are basically saying that 2/3 of the British population live within 1/2 a mile of their local exchange! Utter garbage!

I think it is high time the BT fat cats got stung personally for these false statistics as they are blatantly lying to the British public time and time and time again.

It must be said these numbers are “best case”. Having said that your estimated speed of 27Megs for FTTC is about the average so I don’t totally dispute the logic. Also they are doubling the speed of FTTC so your 27Megs could well end up as 54 Megs in time though we do have to wait and see what the actual average speeds of the faster FTTC will be.

I sympathise with you re your current speeds. My sister lives slap bang in the middle of Cardiff and only gets 3Megs. Her line though has been forecast to provide over 30Megs using FTTC. You should both see a huge difference when you eventually move over to FTTC. If you were lucky enough to live in an area that is going to get FTTP then you would get the full advertised speed.

Anyway good luck with your FTTC timetable. If you are amenable why don’t we arrange to have a chat after you have installed FTTC and we can do a before and after experience comparison. Would be interesting.
All the best

cyberdoyle – is ‘patching up the copper’ what the professionals describe as FTTC? Why shouldn’t public money be used for FTTC if it provides a service?

In the past video is the application that needed faster speeds, and still is, so what does anyone think will require more than 80M for the majority of users?

Thanks for the additional info Tref. Would be happy to let you know when I have the service installed, and we can chat then.

Doubling the speed would be great, but I believe that BT are likely doing that because bandwidth is dropping as more customers take up the service once FTTC is live. I know a few people who were quick to get on the Infinity service and getting high 40Mbps, but after a few weeks the speed progressively dropped to mid – low 3os. They (BT) talk about speeds dropping as a result of tweaks to make the service more stable … which I can understand, but always being the sceptic and thinking the big corps are out there to rake in every penny they can get their hands on, I think contention is largely to blame for slowing speeds.

Fingers crossed for a service that would be MUCH better than what I have now for the new year!

Jason – mind you it is in BT’s interest to have as fast as possible a service out there because faster broadband means ISPs and their customers using more bandwidth which is increasingly how BT makes its money.

I have just read this article and I do hope that B.T will follow their promises. I have just done an internet speed test and the following are the results that I recieved:
Download = 0.16 Mb/s
Upload = >0.01Mb/s (the site did not go any lower)

Considering that the world is going through the ‘technology age’ I think broadband in Northampton should be a bit faster than this. I have read about our exchange (hardingstone) getting an upgrade and we are being upgraded to FTTC, with apparent download speeds of up to 35 Mb/s and uploads of up to 10 Mb/s. These upgrades are supposedly going to be live on 31st December 2011. After this upgrade has taken place I will write another article.

I’d like to add some realistic figures into this article, so people can understand a little better what may happen as FTTC rolls out, followed by the 17a profile, followed by vectoring.

We live in the suburban South East, mainly houses rather than flats. We’re around 600-650m from the cabinet, which is near to being the furthest distance on this particular cabinet (so we’re definitely not rural).

The original FTTC predictions were for 30Mbps down and 6Mbps up. We actually got 35Mbps down and 10Mbps up (IP profiles) and actual speeds of 33Mbps down and 8.2Mbps up. The downstream sync speed is probably around 36Mbps.

People have been seeing their speeds drop as more consumers buy into FTTC. This is expected, as FTTC is mostly limited by the crosstalk from other subscribers – and is the main reason why BT’s speed-checkers consistently under-estimate against actual performance. Crosstalk will be a serious issue.

BT have loudly shouted about the coming “up to 80Mbps” service, which is made possible by the switch to the 17a profile. However, the switch is *also* a change to the frequency band plan (to use the 998 plan). The effect of the bandplan change is to re-allocate some of the existing spectrum to downstream capability and to allocate a lower-frequency chunk of the new spectrum to downstream too. Short lines gain in capability due to the new frequency spectrum, but longer lines gain in downstream capability simply because of the re-allocation.

Here, we have already seen the effect of the 17a profile on the existing “up to 40Mbps” service. Our downstream IP profile has increased to 38716 (suggesting a sync speed of the full 40Mbps) without a decrease in the upstream side. At 600m, our line is too long to get the full benefit from the “up to 80Mbps” service when it arrives, but we’ve seen an immediate improvement already.

But the really exciting development is the one yet to come – vectoring. It doesn’t increase the speed of VDSL, but it does make the theoretical maximum speeds available to almost everyone. By countering the effects of crosstalk, it “undoes” the speed reductions seen as takeup increases, and makes the “up to” figures accessible to an increased distance.

With vectoring on top of the 17a profile, we’d find that 100Mbps would be available out to 600m, 80Mbps out to 1km, and 50Mbps out to 1.5km.

I’m not sure of the exact figures, but the average line length from cabinet to subscriber is well under the 1.5km; I think it is somewhere around the 400-500m mark, but could be wrong on that.

The BT graphs predict that 80% of the country will have access to 50Mbps+, after vectoring has been introduced, and they’ve had their cut of the public funding (I guess they assume they’ll get 100% of it 😉 ). After allowing for FTTP’s share, that figure suggests they believe that around 90% of lines on *every* FTTC-converted cabinet will be within 1.5km and able to get 50Mbps. And that is without taking into account the exchange-only lines that can’t get a VDSL solution at all.

Finally, here’s the breakdown of what each piece of the “technology pie” is expected to bring to the overall speed of my 600m line:
– Original FTTC: 35Mbps (or 44%)
– The 17a profile and 998 bandplan: 20Mbps (or 25%)
– Vectoring: 25Mbps (or 31%)

The question is: When the FTTC rollout completes, is a 600m line an average case for what can be supplied?

Thanks Mike
“The question is: When the FTTC rollout completes, is a 600m line an average case for what can be supplied?”
In a highly urban area there will be a cabinet, and all the houses within 600 metres will be ok if the cabinet has been upgraded to the vectoring and everything else. That is assuming that BT predictions are correct. What you can’t predict is how many are beyond the 600 metres, and how far it will be to the next cabinet. We fell for all the spin and boloney when they rolled adsl out, and insisted for a decade that everyone had access to it. Let us not be fooled a second time. They only admitted a third of the country was underserved once funding appeared.

If they put millions of cabinets in then 600metres could be an average. But they won’t. And many will be miles away and never get ‘superfast’ and the digital divide will grow ever wider, and the money will have been spent, and we will have it all to do again.

Ah found it…

In a “VDSL Primer” document from Openreach, dated 2009, they gave some figures:
– 5,600 exchanges
– 80,000 cabinets
– 28 million pairs (21 million residential)
– [*** A typical D-side (cab-house) distance of 420 metres ***
– A typical exchange-house distance of 3.25km

And a statement of the state-of-the-art back then:
– Absolute max speed of 100Mbps
– Reliable operation to 1.8km
though it was only specified up to 12MHz at the time.

So – 420 metres is “typical”.

Great to see you joining in Mike, sums are deffo not my strong point but maybe you can put me right if this is wrong…
so 14 cabs per exchange?
distance from exchange? the further out they put them the more chance of slowspots appearing.
donut in the middle on adsl or cabinet fed inwards too, in which case that means anyone within a km of an exchange is gonna be ok?
anyone within 1.8km of a cab will get something (up to starts with zero)
considering many round here are over 10km from an exchange, what do you suppose they will get? and there are no cabinets on our rural exchanges, so do you think BT will bother installing any when the exchanges haven’t even got adsl 2 yet? Are the new cabs only going next to existing old ones?


The average number of cabinets would indeed be 14, but I wonder what the spread really is..

For example, our exchange (10,000 subs, and market 3) has 43 cabinets, suggesting 230 subscribers per cabinet. BT’s other figures (21 million residential lines spread over 80,000 cabinets) suggest around 260 subscribers per cabinet. Ofcom used to set a limit of >10k subscribers for being a “market 3” exchange… and we know (from figures elsewhere) that, IIRC, 75% of subscribers are on such market-3 exchanges (12% on each of markets 1 and 2). That means that the big, competitive, exchanges will all have more than 40 cabinets

I suspect that *this* really determines where the cabinets go, and how many there are: a cabinet for each grouping of 200-300 properties.

If somewhere rural is much smaller than this, then I guess they are at risk of having no cabinet nerby, and so suffer from long lines from the cabinet (or, as you say, long lines direct from the exchange).

I suspect that, so far, BT have concentrated all their effort at placing FTTC cabinets next to their existing PCP cabinets (ie next to a ready source of 200-300 subscribers). After getting all this business (the “low-hanging fruit” in crude business terms), the next direction has to involve installing FTTC cabinets elsewhere… and 3 places spring to mind

1) Creation of new cabinets for those “nearby” subscribers on direct exchange-only lines.
These would be close to the exchange building, and placed to overcome the restriction that VDSL2 cannot be used within the exchange itself.

2) Creation of new cabinets for those in smaller rural pockets, where there are maybe 30-100 properties. BT’s quarterly results mention “small DSLAMs” under “NGA Developments”, so you have to wonder if they’re now investigating provisioning to smaller house groupings in the more rural locations.

3) Placing a VDSL2 cabinet in the basement of large blocks of flats. This could be the other use of a small DSLAM.

I know that Manufacturers include mini-DSLAMs in their portfolio specifically to cater for the less dense rural areas; all that is needed is for BT to see a financial business case – which might be helped if some funding can be grabbed from BDUK.

I suspect that, when BT say they can increase their coverage from 66% of the UK to 80% (if they get the BDUK funding), then it is by deploying mini DSLAMs further out in the network, closer to clusters of 30-50 properties.

Unfortunately, I don’t see much help here for subscribers who are 10km from the exchange… unless they happen to be in a cluster that could be served by a cabinet. It could well be that these are the top 10% (or bottom 10%) who will need to be supplied by either a wireless solution, or a satellite-based solution.

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