Earth: Mostly Harmless

The future of xDSL in the UK

January 24, 2005 on 10:59 pm |
Categories: broadband, dsl, technology, uk
Tags: adsl, adsl2+, british-telecom, broadband, bt, dsl, easynet, last-mile, local-loop-unbundling, technology, telecoms, uk

The excellent ADSLGuide.org.uk reports on interesting developments in the U.K. broadband industry:

NICC agrees to support ADSL2+ in the UK The Network Interconnect Consultative Committee seems to have given UK broadband users a massive moral boost yesterday, with the news that is has agreed to support the use of ADSL2+ in the UK copper local loop. Until now the ANFP (Analogue Network Frequency Plan) has favoured VDSL for ultra fast DSL connections, but now it seems a way has been found to allow ADSL2+ and VDSL to co-exist. Most other countries have generally taken a choice over which standard is deployed, so in theory the UK should now be able to use which ever solution it desires. Of course this is assuming the support by the NICC does translate into an ANFP that all the other interested parties do agree too.”

(Via ADSLGuide.org.uk.)

Things have certainly been hotting up of late in the UK broadband marketplace. Easynet has of late been offering its own LLU (Local Loop Unbundling) wholesale service to ISPs, notably its consumer subsidiary UK Online, which recently announced its Broadband 8000 8Mb service for users serviced by Easynet-unbundled exchanges (around 300 at last count). Easynet’s LLU charges are apparently 30-35 per cent cheaper than BT’s wholesale IPstream products.Since OFCOM has announced lower LLU charges, other ISPs should roll out similar products. The Register reports that several are considering buying from Easynet rather than BT.

Personally I’m waiting to see what other providers will offer based on the Easynet wholesale package.

Despite these changes, LLU is still an expensive and troubled business. Furthermore, it doesn’t get around the 8Mb cap imposed by the G.DMT ADSL technology (and the shaky old phone lines we have here). If existing products are already pushing that limit in an immature deregulated broadband market like the UK’s, what hope is there for future bandwidth increases? Obviously the holy grail of broadband is some form of fibre to the premises. While this looks unlikely at the moment in terms of widespread roll-out due to the exorbitant cost of effectively replacing old copper pair phone lines with their glass-fibre successors in every exchange, there is at least progress Stateside on getting fibre a little closer to the home/office. Comcast, SBC and Verizon have all recently been investing in more fibre. In the medium term, there’s ADSL2+, which offer up to 25Mbps up to 1.5km from the exchange (at least in theory), and at further distances should give at the least a 50Kbps speed boost. There are already DSL modems on the market which will support this standard, and it looks like 2+ will be rolled out by the LLU operators as well as BT in the year or two to come. As the quoted article suggests, there is widespread support for this standard.

Longer-term options

It seems that there is a growing synergy between the situations of the telcos and the cable companies. Both are striving for a last-mile solution which is cheap to roll out yet will support, in the longer term, the bandwidth which fibre offers, and will eventually be demanded by customers. Thinking forward a little, VDSL looks like it will be the dominant last-mile technology for very high-speed connections in the coming decade - but to gain its (52Mbps) optimum speeds line lengths need to be less than about 300m.

On this note, it’s interesting that BT themselves have a seemingly workable medium-term solution to the last-mile problem in the UK. BTexact (presumably their research outfit) have presented plans to put fibre as far as their street cabinets, where the DSLAMs (DSL modems operated by telcos) would be housed instead of in the exchanges, thus overcoming the 300m limit.

The benefit of this sort of thing is that it’s relatively cheap to roll out, yet offers most of the benefits of fibre to the home. The costs are comparable to building a cable TV network if you’re not an incumbent telco and have to dig up streets, otherwise it’s simply the cost of a few tens of street cabinets per exchange to make the last-mile connection over copper, and the cost of fibre to the street cabinets. It still might take a little government prodding, or indeed funding, for this to happen anytime (geologically ) soon.