Ofcom's analysis this week of broadband speeds in the UK shows that, for certain services, 97 percent of consumers do not get the advertised speed. Viatel argues that this is a problem also experienced by businesses using contended (bandwidth sharing) broadband networks, but that it is not going to be resolved until changes are made at wholesale level.
Steve Powell, product manager for connectivity at Viatel, believes that many stories covering this issue so far have been trivialising what is a complex issue: "Line speed is not the same as data throughput, unfortunately the two are often being conflated confusing the issue further still. Line speed sets the maximum possible speed for a particular end user while data throughput is the amount of useable information able to traverse the entire end-to-end link - a variable figure that on any service provided via a shared network changes dramatically depending on the time of day and patterns of usage by the users online at the time measurement was taken."
Viatel points out that on newer UK ADSL lines the line speed is always set to be ‘Rate Adaptive', in other words the underlying systems will auto negotiate the maximum speed depending on line quality and line length. ADSL is technically capable of a maximum of 8Mbps, whilst ADSL2+ can achieve a maximum of 24Mbps, but since all lines in the UK are owned and operated by BT, and since BT Wholesale and other wholesale providers only offer a one size fits all ‘Rate Adaptive' ADSL product, there is no way an ISP using newer lines can offer anything but a ‘Rate Adaptive' service. This means that they are all tied into offering the kind of ‘up to' product that Ofcom is complaining about.
"If Ofcom wants this ‘up to' figure to be changed it should be forcing the wholesale suppliers to offer stepped fixed rate services where users might pay a cheaper fee when they cannot obtain a higher line speed, as is the case in many other countries. Until this happens, and for as long as ‘Rate Adaptive' DSL is the technology in use, Ofcom will be fighting a battle the end user cannot win. The reason Virgin Media came out on top in Ofcom's assessment is simply because the Coax/Fibre Hybrid Cable service it provides has a fixed line rate and this is not really comparable with ‘Rate Adaptive' DSL offerings. However when the percentage of throughput was taken into account it was found Virgin cable services were more highly contended with more noticeable throughput speed swings during times of high activity.
"Any service based on a ‘Rate Adaptive' technology should be taken to mean ‘in all likelihood less than the maximum speed mentioned. Until BT and other wholesale providers offer fixed speed DSL products where users can choose to buy a 1, 2, 3, 4, 5Mbps etc. service providers have no choice but to state ‘up to' in their descriptions as that is what they are given to sell.
"It is vital business and end users do not lose sight of the fact most broadband is provided over massively shared infrastructure and is therefore often subject to throughput issues during periods of high demand. For the time being, if businesses need to be sure of the delivered speed for business critical applications or use, 'Rate Adaptive' or any contended service should not be used in place of services such as leased lines, Ethernet or even dedicated broadband lines - not shared.
"Until end to end Quality of Service is available on shared broadband to mitigate against the effects of contention, users should take into account they have purchased the right to participate in the sharing of the network they are using. Bandwidth dedicated to an end user is still too expensive for consumers but is often exactly what businesses need," continued Powell.