VDSL2 stands for Very high-speed Digital Subscriber Line 2, the current latest development in DSL technology.
The VDSL2 standard was approved by the International Telecommunication Union in 2006. In theory, VDSL2 can provide up to 200 Mbps for up- and downstream data rates, whereas ADSL2+ is limited to up to 24 Mbps downstream and 3.5 Mbps upstream. Just like ADSL, ADSL2 and ADSL2+, VDSL2 uses DMT (Discrete Multitone) modulation to transfer data. This method involves splitting the frequency range into separate, independent DMT carriers. There are numerous advantages from this.
Firstly, narrow-bandwidth signals suffer from very low levels of dispersion in their transmission medium (which, for electromagnetic signals, increases with longer wavelengths). Narrow bandwidth signals thus reduce the number of corrections by the receiver, as each carrier is less influenced by neighboring signals.
Secondly, interference can be handled more effectively as it does not affect the entire spectrum and impacts just a small number of carriers. Less data is transported by these carriers until the problem is resolved. The great improvement in VDSL2 performance is based on several factors, which are interdependent directly and indirectly. First of all, the working frequency of 2.208 MHz (ADSL2 +) has been increased to up to 30 MHz with VDSL2.
The increased bandwidth available with VDSL2 provides a much larger number of individual carriers. Whereas ADSL2+ provides up to 512 carriers, VDSL2 works with up to 4,096 carriers. Accordingly, VDSL2 can transport much more information per second than ADSL2+.
Even if one of the most highly advertised features of VDSL2, IP-TV, is of limited relevance in the business environment, VDSL2 offers many advantages for business users.
The significantly higher data rates in particular are attractive to enterprises. VDSL2 can be expected to offer downstream data rates of 50 Mbps and 10 Mbps upstream, although the speeds on offer differ from provider to provider. In comparison, SDSL and SHDSL indeed provide symmetrical up- and downstream data rates, but only of about 2 to 4 Mbps per copper-wire pair.
The high data rates of VDSL allow, for example, fast VPN-based access to data stored on the company network – even when a number of people dial-in to the network by VPN at the same time. Given the high performance compared to previous DSL technologies and the lower price, VDSL2 is an interesting technology for all companies that want to use large bandwidths at low cost. Useful supplements to VDSL2 include UMTS to ensure cost-effective high availability, and ISDN for effective remote maintenance.
WLAN Consulting is an initiative of LANCOM Systems. LANCOM Systems is a leading German manufacturer of wireless LAN technology based on industry standards.