Swirling flow

What is VDSL (Very-high-bit-rate Digital Subscriber Line)?

VDSL stands for very-high-bit-rate digital subscriber line potentially offering broadband users speeds of up to 52Mbs download and 13Mbs upload. VDSL is currently some way off availability within the UK because it relies on Fibre to the Curb and BT’s current infrastructure cannot support VDSL as most of the BT infrastructure in the UK is provided over copper.

VDSL uses similar technology to other DSL technologies and is provided over a twisted copper pair but the quality of copper only allows VDSL to work over short distances hence the requirement for Fibre to the curb or Street. BT are concentrating on their 21CN network which will provide fibre to the curb but this is still some way off completion with estimates put at 2010 with a total investment in the region of £10 billion required.

Because BT own the last mile of copper in the UK we are unlikely to see VDSL service with wide availability for some time yet. The only way we will see VDSL offerings in the near future is from cable providers such as NTL as they own their own fibre network.

DSL Variants

  • ADSL 256kbit/s upload, 2Mbit/s download
  • ADSL MAX Up to 800kbit/s upload, 8Mbit/s download
  • ADSL 2 Plus Up to 1Mbit/s upload 24Mbit/s download
  • Annex M Up to 2.5Mbit's upload 16Mbs/s download
  • HDSL 1.5Mbit/s to 2Mbit/s both ways (full duplex)
  • SDSL 2Mbit/s both ways (full duplex)
  • VDSL 13Mbit/s upload, 52Mbit/s download