Have accountants put paid to G.fast from distribution points?
Just a week since the BT Group highlighted their ambition to deliver 2 million FTTH lines and 10 million G.fast (the G.fast figure was originally announced in July 2015) it is being reported that the G.fast element of the roll-out will be cabinet based rather than distribution point based according to BT's Chief Information Office, Peter Bell who was talking at a Gigabit Europe Event.
For many this represents a massive climb down but importantly BT had never confirmed which deployment method it would use and the trials have explored various methods and it is not rocket science to realise that deploying G.fast from a cabinet that already has mains power to it would be more cost effective. The downside is that the complaints that BT just keeps making the faster go faster will be thrown around even more than usual. Nothing in the comments suggests the FTTH roll-out is in danger, and it is possible that we may see the active kit at the cabinet, and the distribution points that serve business clusters benefit from the FTTH option, in the expectation that since business has been making the case for faster speeds it will see greater take-up.
So if BT does stick to a pure cabinet based G.fast roll-out can it deliver 10 million lines? Well the rough and ready answer appears to be yes, the performance of G.fast is evolving but a reasonable estimate from October 2015 was that G.fast when co-existing with VDSL2 will provide 300 Mbps out to 250 metres and 100 Mbps to just shy of 400m. Pulling together the data from our coverage model we calculate that 41% of UK premises are within 250m of their cabinet which is 12 million premises. For those keen to do their own speculation on what might happen the current line length data for premises to cabinets that are model generates is below.
|Distance from cabinet (metres)||Number of premises||% UK premises|
|< 100m||3.2 million||11%|
|< 200m||8.9 million||30.6%|
|< 250m||12 million||41.5%|
|< 300m||14.9 million||51.5%|
|< 400m||19.6 million||67.7%|
|< 500m||22.7 million||78.4%|
|< 600m||24.6 million||85%|
|< 700m||25.8 million||89%|
|< 800m||26.6 million||91.6%|
|< 900m||27 million||93.2%|
|< 1000m||27.4 million||94.3%|
|< 1100m||27.6 million||95%|
|< 1300m||27.8 million||95.9%|
|< 1500m||28 million||96.5%|
|< 2000m||28.3 million||97.5%|
Of course these figures are based on offering the service from all cabinets, but if performance can stretch 300 Mbps connection speeds to 400 metres then you are quickly looking at a subset of cabinets to meet the ten million line target and it will be calculations like this along with the time and motion and hardware/power costs that the accountants will have evaluated from the various trials that has probably led to a model where enabling perhaps 65,000 to 75,000 cabinets to support G.fast versus 4 million distribution points is much more attractive financially.
The ten million target has a deadline of 2020, and what happens beyond then is a big unknown, if other operators plans actually deliver the BT Group might be facing competition from 11 million or so FTTH lines and 17 million Gigabit DOCSIS 3.1 lines and it is this 'IF' that the decision makers will be evaluating.
The data does take account of exchange only lines which while it will not always seem apparent to those who missed out so far are a dying breed and thus sit in the 2.5% of lines that are an extremely long way from the cabinet or are Exchange Only based.