[richardwigley]

>> "When the data speeds in both directions — downloading and uploading — were the same, there was a lot of electrical interference that slowed data traffic to a crawl.

>> ... such meddlesome interference — known as electrical crosstalk — could be drastically reduced if the download speeds were far faster than the upload speeds."

Cool, so DSL is prevented from increasing the upstream traffic by the physics - not a matter of upgrading the 'boxes' at each end of the wire.

[skrause]

This problem has been solved by VDSL2 for quite a while: http://en.wikipedia.org/wiki/Very-high-bit-rate_digital_subs... - the ratio of downstream and upstream and be configured freely there. Using VDSL2 with vectoring you can now get connections with 100 Mpbs downstream and 40 Mbps upstream in Germany.

[poizan42]

> LR-VDSL2 enabled systems are capable of supporting speeds of around 1–4 Mbit/s (downstream) over distances of 4–5 km (2.5–3 miles), gradually increasing the bit rate up to symmetric 100 Mbit/s as loop-length shortens.

You need to be quite close to the exchange to get the higher speeds. Sounds like it should be a solution to the last mile problem though - strategically place DSLAMS along the fiber where existing copper can be re-routed to it. I have no idea how much this is done.