Broadband speeds never far from the headlines
Thursday 13 March 2008 13:55:31 by Andrew Ferguson

The UK currently has a distinct two tier broadband speed system, those with access to ADSL2+ via an unbundled connection or Virgin Media cable have options that may connect all the way up to 24Mbps. The others are limited to the BT Wholesale ADSL based products which top out at 8Mbps.

As of April 2008 this should change which is nothing new as the roll-out of ADSL2+ by BT Wholesale is hardly news. We expect to see 5% coverage initially ramping up to around 50% in a years time, and roll-out continuing to all ADSL enabled exchanges. This last bit is the key since it means those in areas where the population density is lower and thus less money to be made will stand a chance of seeing better speeds.

While many people get excited about the headline speed, which will triple from 8Mbps to 24Mbps, ADSL2+ is a lot more and the standards it is based on allow for better diagnostics of faults. This means those who have a slow 250Kbps (0.25Mbps) service currently may not see much (if any) connection speed change but may see better throughtput speeds due to less errors.

BT Wholesale has briefed a wide range of journalists on its new WBC (Wholesale Broadband Connect) products hence the flood of news items covering varying aspects (e.g. BBC News Online, PC Pro and ZDNet amongst others).

The issue of interference and noise is possibly more important with ADSL2+, and those on short lines may find to get the most from ADSL2+, a little thought is needed. Various relatively simple things that may help include, not dumping the modem amongst a pile of power supply bricks, removing unused telephone extensions, fitting an ADSL master socket faceplate, or the new simpler system which is an interstitial faceplate that fits over the existing master socket and isolates the ring wire. The latter is possible now but involves a small wiring change. The new BT faceplate fits on without people having to alter any wiring. Changes like this are not going to allow a long line that is 5km long to run at a full 24Mbps, but it may add an extra 10 to 15% of performance and importantly reduce the number of errors making things like gaming and VoIP much smoother.

We see many people worrying that the DLM (Dynamic Line Management) system will continue with WBC, but from the briefing it is a much revamped system with many concerns addressed. The number of profiles is set to increase dramatically meaning the granularity of the IP Profile steps will be a lot smaller than the existing 0.25 and 0.5Mbps. The time for an IP Profile to catch up to line connection speeds will improve, and a lot more historical information will be made available to broadband providers to let them see how a line is performing.

How broadband providers manage these upgrades and explain the possible changes customers may see will be crucial to the public perception of ADSL2+. BT Wholesale is updating its line checker to give an ADSL2+ estimate and broadband providers already know how a customers line is performing, so could send out varying upgrade emails to help manage expectation. Put simply the industry as a whole needs to ensure people are aware that ADSL2+ does not mean everyone will see downloads running at three times their current speed.

Some final news for those on very long telephone lines, interleaving which makes a line more tolerant to errors is set to improve, with a wide variety of settings which may help to improve throughput, additionally the interleaving depth can be set independently on the upstream and downstream directions.

Once BT Wholesale makes available the final details on things like the various profiles and the options available to broadband providers we will pass the information on.