VDSL

VDSL stands for Very-high-bitrate Digital Subscriber Line, a family of DSL technologies designed to provide higher data rates over existing copper telephone lines. It is commonly deployed as fiber to the cabinet (FTTC), where a street cabinet with a DSLAM delivers high-speed connections over the copper pairs that run to homes and businesses. VDSL technologies share the same basic mode of operation as other DSL variants, but are optimized for shorter loop lengths and higher frequencies.

VDSL1, standardized as ITU G.993.1, can deliver up to about 55 Mbps downstream and a few Mbps upstream on short copper loops. Performance decreases with loop length, so practical speeds depend heavily on distance from the cabinet. VDSL2, defined in ITU G.993.2, extends the available bandwidth and uses more flexible profiles, enabling roughly 100 Mbps downstream and tens of Mbps upstream on typical short loops. On very short lines, and with certain profiles, higher rates can be achieved, especially when additional technologies are employed.

To improve real-world performance, VDSL networks may use vectoring, which cancels crosstalk between multiple lines in the same cable bundle. This can lead to higher and more stable speeds. A further enhancement, sometimes referred to as supervectoring (a more advanced VDSL2 profile), can push downstream speeds toward several hundred Mbps on very short copper runs.

End-user equipment consists of a VDSL modem or router at the customer site connected to the existing copper pair, typically via a line filter or splitter to separate voice from data. Deployment is common where fiber is brought closer to premises, while fully fiber-to-the-home remains a separate approach.