Why you'll never see 200Mbps from a 200Mbps 'Net connection

The UK's luckiest Internet users live in Ashford, Kent. Virgin Media announced this week that it is trialing 200Mbps cable connections in Ashford, where 100 "lead adopters" will help Virgin test and evaluate the system. This is a real-world trial that has already escaped from the lab, but it won't be coming to a home near you any time soon; Virgin plans to run its trial for at least six months before looking at the results and considering further deployment. Virgin used the opportunity to talk a bit of smack about cable operators in other countries, claiming that its 200Mbps service "is believed to be the fastest implementation of DOCSIS 3 technology in the world, running faster than services offered in Japan and the US, which currently reach 160Mbps and 101Mbps respectively." This is true, except for the bit where Virgin appears to suggest that its 200Mbps service is, you know, actually available to more than 100 residents of Ashford, Kent. In any event, these numbers (200Mbps, 160Mbps, and 101Mbps) make the DSL and fiber-to-the-home folks livid, because it's not an accurate representation of the speeds that any cable user can achieve in a real-world deployment. (See this post by Verizon's Eric Rabe, for instance, where he calls the cable numbers "a parlor trick.")

Source: http://arstechnica.com/tech-policy/news/2009/05/why-your-cable-internet-connection-gets-slow.ars