The 24Mb broadband myth?

Just recently there have been a slew of ISPs announcing plans to offer superfast broadband speeds of up to 24Mbps based on ADSL2+ technology.

24Mbs, that sound’s great doesn’t it, just imagine all that movie streaming and music downloading. But before you get too carried away, research group Point Topic has just published a sobering piece of research, which, if accurate, shows that only a tiny minority of the UK’s population will ever get anywhere close to these speeds.

The problem lies with the length of copper cable that runs from local exchanges, down your phone line and into your house. Using ADSL2+ technology, 24Mbps is only possible within 300 meters of the exchange.

In effect, to get the maximum benefit from ADSL2+ you will need to be living virtually on top of the exchange. Based on Point Topic’s figures a further 5% of users who live within 500 metres of an exchange will be able to receive 18Mb downstream.

Performance then drops off rapidly so that after 3000 metres the maximum speed available drops to around 8Mbs, effectively the crossover point with current ADSL technology.

Although no figures have been published by BT on local loop lengths, Point Topic says it has been able to use a spot of reverse engineering from available data to come up with the figures.

So does that mean if you want to benefit from the new breed of high speed ADSL services you are going to have to abandon your peaceful detached house in the country for a cramped flat in the city? Well, Point Topics figures are actually a lot more pessimistic than those provided by the Broadband Stakeholder Group to the DTI.

Also, as Point Topic points out, “the distances over which DSL speeds are available are not very clearly defined in practice. DSL services will still work with worse signal-to-noise conditions than the design standards assume.” BT has already successfully used this latitude to extend the reach of standard ADSL.

24Mbps makes an attractive headline for ISPs trying to draw in the punters but, in reality, speeds less than half of this will probably sufficient for most people … for now at least.