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More on souped-up DSL

Faster broadband speeds explained

John Borland Staff Writer, CNET News.com
John Borland
covers the intersection of digital entertainment and broadband.
John Borland

We wrote on Monday about a Yankee Group report (link is fixed this time) that touted the faster DSL speeds coming from VDS2 and ADSL2+ technology. Reader "Kv Raju" asked how these faster DSL speeds were possible without bringing fiber closer to the home.

It's a good question, and in many cases the answer is that the fiber is necessary. VDSL does require a shorter distance between fiber or the central telephone office and the subscriber than does regular DSL. It's a good option for dense urban areas or apartment buildings, and much of the speed advantage that South Korea has over the United States is because of this reason. They have very dense urban centers, run fibers into buildings and use VDSL inside.

ADSL2 and ADSL2+ are different beasts. The first of these allows slightly greater bandwidth over the same distance as today's regular DSL, due to technical advances. ADSL2+ essentially doubles the amount of space dedicated to downloads, doubling speeds over short distances. Once you get about 5000 feet away, the advantages disappear, however.

For a more technical explanation, you can find a white paper on the technologies here (registration required).