When it comes to broadband, it almost certainly doesn't mean what you think it does. As SA Mathieson reports, ISPs are increasingly managing how customers connect.
There's no such thing as a free lunch. And despite what you may have seen in adverts, there's no such thing as an "unlimited" home broadband account, either. One person who discovered this was Stuart Aspland, an NTL Telewest customer in Swansea. Every evening, he'd start using his "unlimited use" 10 megabit per second (Mbps) service; and every evening, its speed would halve after about 20 minutes.
"Technical support tried to tell me there was no such problem," he says. It suggested he restart his connection. He did - and the connection speed halved after 20 minutes. Aspland was almost certainly seeing the results of efforts by NTL Telewest to shape users' data demands. NTL Telewest recently started a technical trial which halves the connection speeds of some 10Mbps users in Swansea, after several months doing so in and around Preston and Blackpool. "We look for abnormal traffic, such as continuous and full use of the downstream over a prolonged period before halving that user's speed," says NTL Telewest. This will return to normal "after a short period unless the abnormal traffic continues. So there's no capping and no cutting off of services."
In an era when we're led to think that bandwidth is plentiful, why is there capping at all? Most ISPs rely on BT Wholesale to do some or all of the work connecting users to their central systems. In 2004, BT Wholesale started offering services priced mainly by capacity - the amount of data that can be carried every second - rather than the number of users or amount of data moved. Angus Flett of BT Wholesale says it now bills most big ISPs this way.
ISPs have to manage users' demands if they are to offer simple-to-understand but cheap services. They do so partly by relying on most customers wanting only a few gigabytes of data each month. But they also have to stop heavy users from overloading their capacity, particularly at busy times. ISPs including Tiscali and Carphone Warehouse connect many users directly to their own networks through local loop unbundling (although often using BT wires between exchanges and these networks) while NTL Telewest has its own cable network, called Blueyonder. But again, the cost of equipment and maintenance is linked to capacity.
Heavy users
To avoid their networks being overloaded, ISPs have introduced techniques such as traffic shaping to slow the heaviest users. "Two or three years ago, 'unlimited' meant something different," says Andrew Ferguson of thinkbroadband.com. "ISPs would tolerate people who really caned a connection for a month - people who used 300, 400, 500GB." But now, he says, many ISPs make it tricky to download more than 40GB. ISPs say these techniques improve the service for most users at the expense of a small minority, such as those making heavy use of peer-to-peer software. Some peer-to-peer users attempt to disguise their traffic through encryption, to avoid traffic shaping.
With fast download speeds, a few heavy users can have a big impact. PlusNet provided Guardian Technology with data for the average usage of each 10% of its customers in December, as well as each percentile of the top tenth. The resulting curve may be less steep than for other ISPs, as it has been traffic-shaping for more than 18 months, but Neil Armstrong, products director, says: "We do have plenty of customers downloading several hundred gigabytes a month; as long as they do it overnight, we don't mind." The top 1% each used an average of 120.94GB, nearly double the 66.03GB used by the next percentile. The average customer used 6.19GB, although removing the heaviest 10% of users cuts that to 2.35GB.
PlusNet caters for heavy users with what could be called a "time-capped" account: it allows users to download 20GB per month between 4pm and midnight, and any amount outside those times. It doesn't use the word "unlimited": "We think unlimited broadband is a complete myth," says Armstrong. "You can only do it by lying to your customers, as the economics don't work."
It prioritises traffic through deep packet inspection, which recognises the kind of software using a connection. Online gaming and Voice over IP phone calls get the most reliable service, then email and web-surfing, then peer-to-peer transfers. Users who exceed their monthly caps go to the back of the queue, but can monitor online how much data they have used, and through which kinds of software.
Jody Haskayne of Tiscali, which labels all its services as "unlimited, subject to fair-use policy", says it cuts the speed of peer-to-peer software when necessary, although not below 10% of the available bandwidth. She adds that most customers use less than 3GB a month, and that telephone complaints about traffic shaping do not enter the top 20 queries. "We have tried capped products in the past," she says. "But customers didn't really understand what they could do."
Some ISPs charge for excess use rather than cutting people off. BT Total Broadband emails such customers, suggesting they upgrade to a higher-volume account. If they do not, from the second month of overuse it charges 30p per gigabyte over the limit. Pipex, Madasafish and Nildram have formal pay-as-you-go plans.
Ferguson of thinkbroadband.com says pay-as-you-go provides clear rules. But the fair-use policies under which demand management is enforced are usually opaque: "If I queue up three or four films and they all download, does that kick me into traffic-shaping?" he says. Mark Jackson, editor of ISPReview.co.uk, says: "This tactic is being employing by an increasing majority of mainstream providers and while the definitions and policies may differ, they almost all share one thing in common: a lack of specific detail."
Following the rules
Some ISPs do publish their rules. For example, Entanet, which has around 60,000 broadband customers, says that when its network's five-minute average usage hits 96% capacity, it cuts the speed of all 8Mbps users by 0.5Mbps, repeating this every minute until capacity drops below 96% or the speed reaches 2Mbps.
In future, more ISPs may sell services with appropriately tailored download speeds. BT Total Broadband says films and television programmes bought from its BT Vision service will not count towards usage caps - unlike material from free services such as YouTube and Joost.
For those who feel unfairly caught out by traffic shaping, persistence may be required. Aspland - who used to work for NTL Telewest - realised he had been caught in the half-speed trial.
He asked to move to a £24.99, 4Mbps connection from his £34.99-a-month, 10Mbps - although usually 5Mbps - service. Then he threatened to cancel broadband, phone and high-definition television. Result: the customer retention department halved his broadband charge and cut the other costs, and he relented. But Aspland still wants his fast connection back. "I've always recommended friends use NTL," he says. "The customer service may be rubbish, but the broadband is great."