Editing VDSL (section)

==VDSL2==
[[File:Armadio PSTN con zainetto G.fast.jpg|thumb|A VDSL2 cabinet on top of a copper cabling cabinet in Italy]]
VDSL2 is an enhancement to VDSL designed to support the wide deployment of [[triple play (telecommunications)|triple play]] services such as voice, video, data and [[high-definition television]] (HDTV) VDSL2 is intended to enable operators and carriers to gradually, flexibly, and cost-efficiently upgrade existing xDSL infrastructure.

The protocol is standardized in the [[International Telecommunication Union]] telecommunications sector ([[ITU-T]]) as Recommendation G.993.2. It was announced as finalized on 27 May 2005,<ref name="vdsl2-press"/> and first published on 17 February 2006. Several corrections and amendments were published from 2007 to 2011.<ref name="VDSL2-spec"/>

VDSL2 permits the transmission of asymmetric and symmetric aggregate data rates up to 300+&nbsp;Mbit/s [[downstream (networking)|downstream]] and [[upstream (networking)|upstream]] on twisted pairs using a bandwidth up to 35&nbsp;MHz on its latest version.<ref>{{cite web | url=https://www.itu.int/rec/T-REC-G.993.2-201501-S/en | title=G.993.2 : Very high speed digital subscriber line transceivers 2 (VDSL2) }}</ref> It deteriorates quickly from a theoretical maximum of 350&nbsp;Mbit/s at source to 100&nbsp;Mbit/s at 500&nbsp;m (1640.42&nbsp;ft) and 50&nbsp;Mbit/s at 1000&nbsp;m (3280.84&nbsp;ft), but degrades at a much slower rate from there, and outperforms VDSL. Starting from {{convert|1600|m|mi|abbr=on|0}} its performance is equal to [[ADSL2+]].<ref name="Tyrone">{{cite web |title= Tyrone Fabrication Ltd., Eircom VDSL |url= http://www.tfl.eu.com/project2.htm |access-date= 8 March 2012 |archive-date= 31 January 2012 |archive-url= https://web.archive.org/web/20120131160406/http://www.tfl.eu.com/project2.htm |url-status= dead }}</ref>
[[File:PCCW DSLAM Cabinet.jpg|thumb|A VDSL2 [[Digital subscriber line access multiplexer|DSLAM]] Cabinet installed by [[PCCW]] in [[Pat Heung]], [[Hong Kong]]]]
[[File:Openreach Man at cabinet.jpg|thumb|An [[Openreach]] engineer works at a [[Internet in the United Kingdom|UK VDSL]] cabinet]]
[[ADSL]]-like long-reach performance is one of the key advantages of VDSL2. LR-VDSL2 enabled systems are capable of supporting speeds of around 1–4&nbsp;Mbit/s (downstream) over distances of 4–5&nbsp;km (2.5–3&nbsp;miles), gradually increasing the bit rate up to symmetric 100&nbsp;Mbit/s as loop-length shortens. This means that VDSL2-based systems, unlike VDSL systems, are not limited to short [[local loop]]s or MTU/MDUs only,{{clarify|date=May 2019}} but can also be used for medium range applications.

[[Channel bonding|Bonding]] (ITU-T G.998.x) may be used to combine multiple wire pairs to increase available capacity, or extend the copper network's reach. [[Hybrid Access Networks]]
<ref name="BBF-TR348">{{cite web |url=https://www.broadband-forum.org/technical/download/TR-348.pdf |title=TR-348 Hybrid Access Broadband Network Architecture|last=Broadband Forum|date=2016-07-01|access-date=2018-07-01}}</ref> can be used to combine [[xDSL]] with wireless networks. This enables network operators to provide faster Internet access services over long lines.

=== Vplus/35b ===
Vplus is a technology to achieve higher speeds over existing VDSL2 networks. It was developed by [[Alcatel-Lucent]] and standardised in November 2015 in ITU G.993.2
Amendment 1 as VDSL2 profile 35b.<ref name="VDSL2-spec"/> It promises to deliver speeds of up to 300&nbsp;Mbit/s downstream and 100&nbsp;Mbit/s upstream on loops shorter than 250&nbsp;m. On longer loops, Vplus falls back to VDSL2 17a vectoring performance.<ref name="35bvect">{{cite web |url=https://techzine.alcatel-lucent.com/vplus-gets-more-out-vdsl2-vectoring |archive-url=https://web.archive.org/web/20150725134126/https://techzine.alcatel-lucent.com/vplus-gets-more-out-vdsl2-vectoring |url-status=dead |archive-date=25 July 2015 |title=Vplus gets more out of VDSL2 vectoring |author1=Keith Russell |author2=Paul Spruyt |author3=Stefaan Vanhastel |publisher=[[Alcatel-Lucent]] |date=16 October 2014 }}</ref>
Vplus uses the same tone spacing as VDSL2 17a to allow vectoring across Vplus (35b) and 17a lines, and thus mixed deployments and a smooth introduction of Vplus.<ref name="35bvect"/>