Very high data rate Digital Subscriber Line

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VDSL or VHDSL (Very High bit rate DSL) is an xDSL technology providing faster data transmission over a single twisted pair of wires. Compare HDSL (High data rate Digital Subscriber Line).

The maximum available bit rates are achieved at a range of about 300 meters (1000 ft), which allows for 26 Mbit/s symmetric access or up to 52Mbit/s down – 12Mbit/s up asymmetric access.

The Infineon 10Base-S™ (Ethernet over VDSL) technology delivers 10Mbps, full duplex Ethernet over existing copper wire infrastructure up to 4000ft/1200m.

Broadcom offers V-thernet solution.

Currently, the standard VDSL uses up to 4 different frequency bands, two for upstream (from the client to the telco) and two for downstream. The standard modulation technique is either QAM (Quadrature amplitude modulation) or DMT (Discrete multitone modulation) which are not compatible, but have similar performance. The current mostly used technology is DMT.

These fast speeds mean that VDSL is capable of supporting new high bandwidth applications such as HDTV, as well as telephone services (Voice over IP) and general Internet access, over a single connection.

A new VDSL standard is now available, named VDSL2.

[edit] Supply

As of 2006, the market is still small, except in Japan and South Korea, where VDSL is predominant.

  • Belgium
    • Belgacom is providing VDSL in parts of the country (about 6% coverage), but limited to 17 Mbit/s down, 400 kbit/s up and with a monthly download limit of 30 GiB.
  • Finland
    • Provided in Oulu by OPOY and in Turku by Auria. The services provided in Turku and Oulu are actually based on Cisco's LRE. A few universities also provide fiber-optic VDSLs to their students.
  • France
    • Erenis is offering both internet and telephone over VDSL in Paris. The broadband is 60 Mbit/s down and 6 Mbit/s up [1]
  • Germany
    • VDSL2 is currently available in 10 major cities with up to 25 Mbit/s downstream and 5 Mbit/s upstream. The technology is being used by former incumbent Deutsche Telekom who is planning to invest ca. € 3 billion to set up the requisite VDSL infrastructure in 50 cities until ca. 2007; despite a ruling by the European Commission in December 2004 that would force the company to make parts of this new infrastructure immediately available to competitors, deployment is ongoing. The extent and the terms of infrastructure access are still to be determined.
  • Hong Kong
    • VDSL is offered by HGC. A 10 Mbit/s up and down connection costs less than $15 USD/month with a 12 months contract. $20 USD/month without any contract. Both with unlimited traffic.
  • Japan
    • VDSL is indirectly offered in many areas by NTT, Japan's largest telco in conjunction with FTTH service. It is used as a mechanism to wire apartments and other existing construction as a lower cost alternative to pulling optical fiber to each unit.
  • Netherlands
    • VDSL Roll-out is tested by the company KPN and is expected in Q2 2006 to be used. ADSL2+ is already being used on large parts of the network.
  • Slovenia
    • VDSL appeared on 1 October 2005. It is provided by T-2.net, offering triple play services with internet speeds ranging from 1 Mbit/s/256 kbit/s to 40 Mbit/s/15 Mbit/s at more than 120 locations across the country. A 10 Mbit/s/10 Mbit/s connection costs around €50 per month.
  • South Korea
    • VDSL is offered in apartments by KT and other several providers, costing about $20-$40 USD/month.
  • Spain
    • VDSL Roll-out by Telefonica began in 2005 in selected places in Madrid. Commercial launch up is planned for 2007.
  • Taiwan
    • VDSL available in Taiwan in form of Fiber to the Building (FTTB) service provided by Chunghwa Telecom, the largest telecommunication company in Taiwan. FTTB has a maximum connection speed up to 10 Mbps downstream and 2 Mbps upstream.

[edit] External links

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