Following the broadband money

Read this to avoid broadband blues

with 15 comments

The publication of uSwitch’s fastest and slowest broadband lines in the UK prompted some debate on Twitter and the various websites that followed the story.

From the many comments it is clear that there is little agreement on what users can or should expect. In fact, a glance through the official confidential BT Wholesale FTTC Handbook shows that buying broadband in the UK is more like buying a pig in a poke than an engineered service.

Compared to the marketing hype and disinformation around BT’s fibre to the cabinet (FTTC) product, the handbook is remarkably clear. The handbook used as the basis for this article was published in January 2011. Since then BT has doubled the frequency of the network, so the “up to 40Mbps” service is now, theoretically, an “up to 80Mbps” service.

It may be that BT has updated the handbook in the light of the frequency change. If so, it should feel free to provide Br0kenTeleph0n3 with the update, and we would be happy to update the story below.

However, there are constraints on the FTTC service that won’t change. These are important for users to know when they come to decide whether they are getting value for money and what to do about it.

What follows is based on the January 2011 handbook, so please use your own judgment to adjust for the frequency change, or better still, ask your broadband provider what the position is for your service.

The best you can get?

Firstly BT will accept orders for service activation only if BT’s Broadband Availability Checker (BBAC) indicates the line will deliver a download line rate (ie from the street cabinet to your home) of at least 5Mbps.

The standard product available to broadband providers is a 40/2 line rate. This is a “best effort” downstream flow of up to 40Mbps, with an “up to” 2Mbps upstream flow.

Where the upstream line could perhaps run at more than 5Mbps, service providers have the choice to offer a 10Mbps upstream flow. i.e. a 40/10 service.

Readers should be aware that there are mixed opinions as to the accuracy of the information produced by the BBAC. However, it determines what BT will offer the market.

Where the BBAC indicates the maximum potential download speed is between 15 and 5Mbps, service providers can ask for the service to be discontinued (for free) if the “line rate”, also known as the “synch speed”, is continuously below 5Mbps for more than a quarter of a fortnight, ie 84 consecutive hours.

What speed am I really getting?

Customers should be aware that there will be a difference between the line rate (line speed) and the throughput experienced end to end by the end user.

Line rate/Line speed refers to the synchronisation speed negotiated between the VDSL router (in your home) and the street DSLAM (cabinet) that supplies the service.

Throughput refers to the ability to pass data through the network at a given rate. This depends not only on the synch speed but also the available bandwidth between the end user and the source of the data through the BT Wholesale and service provider networks, and often the internet itself.

BT uses line speed as the threshold for accepting faults; users are more interested in throughput, because that determines how long they wait for their iPlayer movies to download, etc.

What can go wrong?

BT warns, “The actual rates that can be supported on any individual line will be influenced by two main factors. Firstly the distance of the copper connection from the end user’s premises to the street cabinet, and secondly, the number of end users signed up and using the common cable (simultaneously) which will determine cross-talk noise impact. Either of these two factors may result in the end user experiencing a drop in the speed from what was originally achieved” (ie. the synch speed).

Is that all?

Not quite. BT says its network dimensioning rules are there to ensure that customers receive a “given IP throughput” (ie. number of packets of data) based on the product they have bought. This is “regardless of the activity of other users within this shared part of the network.”

Users on “standard” packages will get at least 12Mbps for 90% of the three hour “busy” period; users on a premium or “elevated” service will get at least 16Mbps for 90% of the busy period.

Users whose synch speed is 5-15Mbps are treated a little differently. “Standard” package users will get “at least 70% of the value of their BRAS (Broadband Remote Access Server, of which there are 20 scattered around the country) profile for 90% of the busy period (ie 63% of synch speed), while users on “elevated” packages will get 80% of the value of their BRAS profile for 90% of the busy period (ie 72% of synch speed).

Thus, for practical purposes, BT has a contractual commitment to deliver a broadband service with a line speed of just 3.15Mbps. Note that this may have changed to 6.3Mbps following the doubling of the nework frequency.

Once the service is in, BT allows 10 days for the line to “stabilise”. It then sets a Fault Threshold Rate (FTR) at 5Mbps downstream for services provided at up to 15Mbps downstream and at 15Mbps downstream for faster services. The FTR is the line rate below BT will accept and investigate faults.

Anything else?

FTTC services are not available to the 11% of households that are on “exchange only lines”. Lucky EoL homes may have direct access to BT’s Generic Ethernet Access (GEA) service for broadband.

Transmission performance of some metallic local loops will mean that it is technically impractical to deliver the FTTC service to all end users within the serving area of an exchange (ignoring EoLs).

The service may also affect the performance of some traditional customer premise equipment. Voice band modems used by fax machines and by personal computers may run slower.

Some technical limitations within the BT network may not become apparent until after the service has been installed and working for some time. In such circumstances the service for some individual end users may need to be withdrawn.

Downstream and upstream burst rates may be reduced by overbooking (ie congestion) within the BT network.


Written by Br0kenTeleph0n3

2012/11/10 at 18:19

Posted in Broadband, Internet, News

Tagged with , , ,

15 Responses

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  1. Well they can’t turn round and say they weren’t warned now can they? What a shame public money is going into this fiasco. If only we could get the councils to study the facts before they hand over all our hard earned taxes to an incumbent leeching the last vestiges of income from its obsolete assets. If they would just be truthful and explain it all properly and say ‘we’re doing the best we can with what we have and this is what you will get’ – then I wouldn’t mind a bit. Good luck to them. But to tell everyone they are going to get ‘superfast’ is just plain wrong. So wrong. Tell the truth and shame the devil my gran used to say. Shame is that they are not telling the truth to the councils and government.


    2012/11/10 at 18:46

    • Why is it a fiasco? This is how the technology works, this explains it. Presumably many people are happy with it.

      How much would the government have to provide to get FTTP everywhere? Please reply to move the discussion along.


      2012/11/10 at 18:53

      • Perhaps the government (central and local) should stop promising what it can’t deliver, and get out of the way so people can do what they need to. We can certainly spend the tax money more efficiently than they can.


        2012/11/11 at 00:31

    • Well, you can download the handbook and give it to local authorities. It’s only 72 pages, and the relevant bits are all at the front, so those with short attention spans won’t miss out 😉


      2012/11/11 at 00:28

  2. Uswitch say:

    ‘In order to be included in the tables of slowest or fastest streets, streets had to have at least 30 registered speed tests.’

    However they just ask for postcode and the 30 tests could be from the same property, hence the huge difference between the checker number and the Uswitch one in some cases. A very poor analysis.


    2012/11/10 at 18:49

  3. The point being made is that we are being mislead. There is no argument about how FTTC works. Local authorities seem to be very optimistic about the speeds that FTTC may produce. Engineers have been telling the politicians and non-engineer officials the facts about FTTC limitations. These latest revelations by Broken Telephone shows that even BT Openreach understand the limitations. However, the marketing jargon developed by the industry is now also being used by politicians, as they hope that this will make most people (voters) believe that they will deliver on their promises.

    As one example of such optimism, Surrey County Council has stated that their contract with BT is for extended deployment of their NGA network to cover 99.7% of the county. This is for a combination of FTTC and some FTTP in order to achieve speeds of up to 80mbps and will involve installation of new cabinets and upgrading of lines where needed. For the remaining 0.3% of premises Surrey County Council says they will explore possible alternative solutions/ technologies or local community finance, in order to provide superfast access.

    I suppose that most will be content to wait to see if this is delivered. Current BT Openreach deployments suggest that unless radical changes are made to accommodate the rural challenge there is no way that the Surrey County Council ambition will be met. What’s more the FTTC deployments are not FTTP upgradable based on the current deployment practice. It is as ever the same old story, Ever since the world began, Everybody got the runs for glory, Nobody stop and scrutinize the plan, Nobody stop and scrutinize the plan – with apologies to Paul Simon.

    David Cooper

    2012/11/10 at 21:27

    • Spot on David, and by the time they are found out those who handed them our money will have gone, with fat pensions and the whole job will be to do properly. Whereas if they listened to us now we could at least make a start at doing it right instead of wasting our money on temporary fixes to fool the voters.


      2012/11/10 at 21:39

    • Fibre on demand (FTTP) will be available to all FTTC areas from next Spring. There will of course be a cost to this, which may be subsidised by ISPs. However, if the digital village pump idea, touted by the House of Lords, was implemented consumers would still have to pay for the laying of fibre from the PoP to their property. At least with FTTC consumers get a faster connection without a significant increase in cost but have the option to upgrade to FTTP should they choose to do so.


      2012/11/11 at 22:27

      • Yes, BT’s been signalling that for some time. What’s not clear yet (to me at least) is whether its FTTP service will be a point to point service (i.e. from the exchange to the end user’s premises) or via GPON, or what the costs are likely to be. It is also not clear to me why BT is doing this. It has made available FTTC to 12 million homes, and apparently fewer than one million have taken up its offer, despite, as you note, there not being a significant cost premium. Does it honestly expect a sudden surge in demand for FTTP when it has been so adamantly opposed to it? The more one thinks about it, the more it (and your comment) feel like straw men designed to hurt the activities of true FTTP altnets like B4RN, B4RS and Gigaclear. The sooner BT comes out with terms, conditions and prices for its FTTP on demand product, the sooner we can all move on. Until then, its statements about FTTP must be treated with scepticism because its motives remain suspect.


        2012/11/11 at 23:12

      • I have yet to see a detailed technical and financial definition of a DVP.

        Clearly BT and the business and residential ISPs see a demand for FOD FTTP, so what’s the problem? Why not contact Sky, TalkTalk, Timico etc. to see what they say about it. It won’t affect altnets if they are not in FTTC areas.

        Where has BT been adamantly opposed to FTTP, other than for financial reasons, what about FOX?

        Is the FTTC take up something to be concerned about, we are told here that we will need more bandwidth soon, eventually so much that FTTC will be insufficient.


        2012/11/11 at 23:46

      • Ian, BT FTTP will be GPON which has been shown will do 10Gb/s using the XG-PON standard. FTTC take up is increasing as the footprint increases. I admire the efforts of B4RN and others and wish them the best but I don’t understand your comment about BT’s motivation for FTTP being suspect. You, and others that post on your blog, champion FTTP so why the scepticism towards FTTP provided by BT? I can’t see BT’s solution being any more expensive then it would cost me to connect to a digital village pump if one was available.


        2012/11/12 at 15:15

      • People can already buy an FTTP product from BT, but it’s unaffordable for the average person. BT’s statement of intent, without details of prices, terms and conditions, in effect creates uncertainty and doubt among altnet’s potential customers. The regulators, including the Competiton Commission needs to assess whether this is fair practice.


        2012/11/13 at 08:27

      • With trials and pilots for FOD taking a year to establish the technical and commercial aspects what’s the alternative?


        2012/11/13 at 09:09

      • You mean BT has no information from Ebbsfleet or Milton Keynes? Besides, BT invented this technology. Are you being wilfully stupid?


        2012/11/13 at 10:24

  4. The term “fibre on demand” appeared at the time BT were tendering to local authorities and appears to now be used by BT and local authorities to support the requirement that public money should be seen to be spent on a sustainable future-proof infrastructure. Surrey County Council say, “BT have also announced a ‘fibre on demand’ consumer product, which will enable anyone on an FTTC solution to order a fibre overlay for the copper part of their line at a set consumer price. This would enable speeds of up to 330mbps to be achieved. BT are currently developing the cost for this service and it will be available to any home or business on BT’s NGA network across the country.”

    Ian’s comments about the straw men and FTTP on demand seem to be supported by observations of the FTTC deployments which mean that we should be sceptical about BT’s commitment to FTTP on demand (GPON or XG-PON). Can someone explain just how BT are to engineer FTTP to the extremities of an area, given there are only 4 fibres in each FTTC? Also, for a 32 way splitter for GPON (or XG-PON) fibre, will it need all demanders of fibre to be on the same splitter and use the same ISP and how many will be required to make it a commercial proposition?

    Perhaps BT hope that demand wiil be so low that these practical problems will never need to be addressed. Never-the-less, these questions need to be put to BT by local authorities as sooner or later the demand for FTTP will materialise and tax-payers could be asked to pay to do the job again.

    David Cooper

    2012/11/12 at 23:24

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