Tag - vdsl2

Our Top Ten Most Frequently Asked Questions About VDSL

We’ve compiled a list of the most commonly asked questions about VDSL & VDSL2. If you’re interested in learning more about ADSL and ADSL2+, visit our ADSLs/2+ FAQ here.

1. What is VDSL/VDSL2?

VDSL, or Very-High-Bit-Rate Digital Subscriber line, allows Internet Service Providers to provide fast connection speeds via legacy copper lines. VDSL and VDSL2 can provide faster broadband performance when compared to ADSL/2+ up to approximately 1.5km distances. After 1.5 km distances, VDSL2 exhibits performance rates comparable to ADSL2+.

2. How fast is VDSL in comparison to VDSL2?

VDSL speeds vary depending on copper loop lengths and other factors in a networking environment. Pair-bonding is another factor that influences VDSL speeds. VDSL can support downstream and upstream rates of 100 Mbps. VDSL2 on the other hand, can reach theoretic downstream and upstream data rates of up to 200 Mbps at its source. VDSL2 also supports a wider frequency range of 30 MHz in comparison to VDSL’s 12 Mhz frequency range. Both VDSL generations quickly deteriorate after certain distances. At 1 km, both VDSL versions begin to exhibit similar speeds. At approximately 1.6 km, VDSL performance becomes comparable to ADSL2+. VDSL vs VDSL2 Comparison Chart

3. What is the farthest distance VDSL2 can reach?

The maximum range for VDSL2 is approximately 1,200 meters. After approximately 1600 meters, VDSL2’s performance quickly deteriorates yielding speeds comparable to ADSL2+.

4. How does VDSL2 achieve higher data rates than VDSL and ADSL2/2+?

Copper loop lines are susceptible to signal attenuation and copper loop lengths which limit fast transmission speeds. To achieve data rates over 100 Mbps, VDSL2 relies on port-bonding and vectoring.

5. What is pair-bonding?

VDSL2 supports the capability of bonding two or more twisted copper pairs to increase banding. But pair-bonding also functions to extend the reach of a copper network. Two DSL Line circuits that connect to a customer’s modem can be bonded. Or as explained by Ospmag, pair-bonding requires 2 VDSL2 lines which “can be combined into a “virtual “gig pipe” that allows operators to double the bitrate for existing subscribers.” Pair-bonding can be compared to adding more lanes to a freeway so that it can support more traffic. This enables Internet Service Providers (ISPs) to offer different data rate packages to subscribers.

6. What is VDSL2 Vectoring?

VDSL2 uses vectoring to remove crosstalk and interference reduces actual performance. VDSL2 measures crosstalk from all lines in a network and applies anti-phase signals to cancel out noise. VDSL2 vectoring works in similar fashion to noise-cancelling headphones. Crosstalk allows VDSL2 speeds to achieve longer distances than VDSL.  Assia Inc.  specifies that “Vectored VDSL is most suitable for deployment from a node, and is the most economical in terms of required capital expenditure.”

7. What is the purpose of the different VDSL2 profiles?

VDSL2 supports 8 distinct “profiles” with varying maximum downstream and upstream throughput as well as different bandwidth frequencies and transceiver power. Different profiles are optimal for different deployment scenarios. For example, profiles 8a-8b and 12a-12b are ideal for Fiber to the Node (FTTN) deployments. Profiles 17a can be used for Fiber to the Cabinet (FTTCAB), and Fiber to the Building (FTTB) can utilize profile 30a.
Different VDSL Profiles

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8. Do you recommend using 2 different VDSL2 profiles on distinct modems connected to a DSLAM?

Having a cable bundle consisting of 2 or more VDSL2 profiles will exhibit intermittent sync, port status errors and poor performance. The 30a profile will run on 30 Mhz while the 17a profile will run on 17Mhz. The 30a profile can "bleed" over to the 17a profile.  Many chipset manufactures such as Broadcom have stepped away from VDSL2 30a due to this very reason. Our recommendation is to force all subscriber interfaces to sync at 17a if you have modems that do not support 30a. Users shouldn't have an issue if all ports are synced on the same VDSL2 profile.

9. Are VDSL2/2+ units compatible with previous versions of VDSL2?

VDSL2 units are backwards compatible with VDSL Units. When a VDSL2 unit is connected to a compatible VDSL unit, VDSL2 bandwidth will revert to VDSL’s maximum supported 12Mhz frequency range.

10. Are there faster DSL technologies than VDSL2?

Yes! G.Fast is a standard still in development that has shown the ability to transmit gigabit speeds using legacy copper lines in laboratory settings. Openreach, the dominant telecom provider in the UK, is spearheading the new technology, deploying trial runs to determine if the new technology is commercially viable. However, G.Fast, like VDSL, is only effective in deployments where customer premises reside near cabinets. To learn more about G.Fast, click here.

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If we were to roll out a new G.Fast DSLAM, how many ports would it ideally support?
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XDSL speeds

Different xDSL Equipment Overview

DSL has come a long way since its humble ADSL beginnings. The following is the final part in The History of DSL Trilogy. If you missed the Part I discussing the history of DSL, click here.  For a quick overview  of the 6 xDSL technologies in use today, visit Part II of the series.  Receive a Complementary Consultation

Equipment Used For DSL

There are a range of products on the market that deploy DSL services. The following are a few examples of Digital Subscriber Line Access Multiplexers (DSLAMs) and modems that deliver DSL broadband. Visit Part II of this series to learn more about the different types of DSL.


Some ADSL DSLAMs are compatible with all three ADSL standards such as the VX-1000HDX and the VX-1000MDX.
best DSLAM

The VX-1000HDX ADSL2+ IP DSLAM unit from Versa Technology is a mini-DSLAM designed for the deployment of access networks.


The VX-1000MDX ADSL2+ IP DSLAM unit from Versa Technology is a mini-DSLAM that supports ADSL, ADSL2/2+ AnnexA and AnnexM.


Some VDSL2 IP DSLAMs such as the VX-M2024S and the VX-MD4024 come with ADSL2/2+ ports for added flexibility.  

The VX-M2024S from Versa Technology is a 1.5U compact 24-port VDSL2 IP DSLAM with 2 Gigabit Ethernet Combo interfaces and built-in POTS/ISDN splitter.


The VX-MD4024 is a rack-mountable VDSL2 IP DSLAM. The unit supports two Gigabit Ethernet (GbE) trunk interfaces and 24 VDSL2 ports (ADSLx backward compatible).

VDSL2 Modems

Many VDSL2 modems offers ADSL2+ fallback such as the VX-VER522.

Versa Technology's VDSL2 with ADSL2+ fall back 802.11n router has integrated wireless 802.11n draft 2.0 technology, making it possible to provide high-speed wireless data rates of up to 300mbps and superior wireless coverage.


Most ADSL2+ modems support ADSL2 fallback such as theVX-VER170S.  

The VX -VER170S ADSL2+ bridge/router from Versa Technology provides advanced long Reach/Rate, and crosstalk-free technology.

Limiting Factors

One of the main limiting factors to DSL services is aging copper lines. Companies that seek to compete at fiber speeds like Verizon Communications and AT&T, have been accused of allowing their copper lines to deteriorate so as to replace them with fiber. In fact, Verizon communications has recently sold its wireline liabilities to Frontier Communications, a smaller telecom company that delivers DSL broadband to rural cities.  Another limiting factor to DSL is that subscriber speed directly correlates with how far away subscribers reside from the exchange.

The Future of xDSL

Even though DSL subscribers are declining, ISPs still desire to retain the profitability of copper lines. ISPS are investing in researching new vectoring methods to transmit broadband at faster speeds.  As WinterGreen research reports: “Copper represents an installed infrastructure worth trillions and too expensive to just replace. Fiber is too expensive to use it to replace all the copper.” The utility of copper lines will continue to defy the laws of obsolescence with improved vectoring methods such as G.fast and XG.Fast, which have successfully achieved downlink speeds of 1 Gbps and 5 Gbps respectively. Openreach has already begun trial test runs with the new chipset to determine its integrity in real world settings.  G.fast is still considered bleeding edge technology, but supporting standards such as G.inp promise to stabilize the consistency of signal speeds. To learn more about G.imp click here.  

Take Our Poll!

If we were to roll out a new G.Fast DSLAM, how many ports would it ideally support?
Fill out my online form.

ADSL2 + and VDSL2 Technologies from Versa Technology

ADSL2 + and VDSL2 technologies are dependable solutions that provide users with stable network connections and speed. Versa Technology features state-of-the-art equipment to meet the demands of both ADSL2 + and VDSL2. The two technologies feature varying benefits: What is VDSL2? VDSL2 is the most advanced standard of DSL line communication and supports a variety of triple play services. VDSL2 is ideal for services such as high definition TV, online gaming, voice, video and data. This technology allows service providers the ability to upgrade current xDSL infrastructure cost effectively. VDSL2 technology features a downstream rate of up to 100 Mbps and an upstream rate of up to 100Mbps or 50Mbps. VDSL2 is utilized as a solution in locations where FTTx cannot reach MDU points. It is also used when fiber speed cannot be deployed further with traditional copper. Since speeds with VDSL2 are comparable to fiber, it is a great choice because as it saves on costs by utilizing existing copper. The protocol is standardized by the International Telecommunication Union telecommunications sector (ITU-T) as Recommendation G.993.2. VDSL2 is an improvement to standard VDSL and allows transmission of asymmetric and symmetric aggregate data rates at a maximum wire speed of 200 Mbit/s utilizing twisted pairs on a bandwidth up to 30 MHz. Although the technology has performance superior to VDSL, it also has the ability to deteriorate. The technology degrades at 1.6 km and then VDSL2 performance is the same as ADSL2+. Receive a Complementary Consultation What is ADSL2+ ? ADSL2 + technology is most commonly deployed as equipment becomes more affordable and plentiful, including ADSL2 Modem units. This technology is typically deployed in locations where line quality is questionable or in rural areas. ADSL2 + lengthens the ability of standard ADSL and increases the number of downstream channels. Data rates with ADSL2+ can be up to 24 Mbit/s downstream and a maximum of 1.4 Mbit/s upstream depending on the distance. ADSL2+ is able to increase the frequency band of standard ADSL from 1.1 MHz to 2.2 MHz. This technology doubles the downstream data rates of standard ADSL2, which was a maximum of 12 Mbit/s. However, like many standards, ADSL2+ will degrade from its highest bit rate after a distance. ADSL2 + permits port bonding in which many ports are provided to end users. The bandwidth is then the same as all ports. This allows the finished result to be a connection that features, for example, 48 Mbit/s of download speed and double the original speed for uploading. Port bonding with ADSL2 + is also referred to G.998.x or G.Bond and is not available on all DSLAM units. Versa Technology offers user friendly equipment, including VDSL2 modem  solutions, to create dependable and secure networks. Connect with us today! Check out our xDSL Porducts
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