DSL is a very popular technique that is used in today’s time all over the world. The full form of DSL is a digital subscriber line. DSL is used to convert the telephonic lines into broadband transmission lines to act as a communication link.
Summary
The techniques of DSL can be done in two different ways. These different ways are also known as the two variants of the DSL, which are, ADSL and VDSL. Though both variants have the same objective, they work differently and have many dissimilarities as well.
ADSL vs VDSL
The main difference between ADSL and VDSL is that the speed of ADSL is very low as compared to the speed of VDSL. While on the other hand, the speed of VDSL is almost twice that of the speed of ADSL.
The full form of ADSL is an asymmetric digital subscriber line. As the name suggests, ADSL provides asymmetric or unequal bandwidths in the case of upstream and downstream. That is to say, the speed of upstream provided by ADSL will not be equal to the speed downstream.
The full form of VDSL is a very high-bitrate digital subscriber line. The technique is quite similar to ADSL but has a couple of advancements in it, such as in terms of speed of upstream and speed of downstream.
Comparison Table Between ADSL and VDSL
| Parameters of comparison | ADSL | VDSL |
| Full form | Asymmetric digital subscriber line | Very high-bitrate digital subscriber line |
| Speed | Both upstream and downstream speed of ADSL is slow as compared to the speed of VDSL. | Both upstream and downstream speed of VDSL is fast as compared to the speed of ADSL. |
| Modulation used | Modulation used by ADSL is either cap carrier amplitude-phase or discrete multitone technique (DMT). | Modulation used by VDSL is the discrete multitone technique (DMT). |
| Common protocol | The common protocol followed by ADSL is PPP. | The common protocol followed by VDSL is ATM. |
| Usage | ADSL is used more extensively as compared to VDSL. | VDSL is used less extensively as compared to ADSL. |
| Type of data | ADSL can handle only asymmetric types of data. | VDSL can handle both types of data, that is asymmetric data and symmetric data as well. |
| Cost | The cost of ADSL is less as compared to the cost of VDSL. | The cost of VDSL is more as compared to the cost of ADSL. |
What is ADSL?
ADSL or also known as an asymmetric digital subscriber line that covers plain old pot (POT) and asymmetric data. The speed of upstream and speed of downstream in the case of ADSL is slower as compared to VDSL, however, the technique is still widely used as compared to VDSL. The reason behind that is because ADSL covers a large distance as compared to the VDSL technique.
The ADSL technique works by splitting the cable bandwidth into three different asymmetrical bands. These three asymmetrical bands are then used for different purposes, each having a different bandwidth. The first band is used for telephone services, also known as POT services. The first band has a bandwidth ranging from a minimum of 0 kHz to a maximum of 25 kHz.
The second band is used for upstream services. The second band has a bandwidth ranging from a minimum of 20 kHz to a maximum of 200 kHz. Lastly, the third band is used for downstream services. The third band has a bandwidth ranging from a minimum of 200 kHz to a maximum of 1 MHz.
What is VDSL?
VDSL or also known as the Very high bitrate digital subscriber line is a bit different technique from ADSL. VDSL uses the Discrete multitone technique or also abbreviated as DMT as its modulation method. The DMT technique is formed by two different techniques known as FDM and QAM.
VDSL is a lot better technique as compared to ADSL. There are many reasons behind why VDSL is more efficient than ADSL, such as it uses several different bands to customize the speed of upstream and the speed of downstream such that maximum possible speed is provided to the user.
Moreover, VDSL also has a higher capacity value as compared to the ADSL technique. However, VDSL covers a short distance as compared to the ADSL, which is equal to about 4500 feet.
Main Differences Between ADSL and VDSL
- The upstream speed in the case of ADSL is slow as compared to the VDSL, which is about a minimum of 64 KB per second to a maximum of 1 MB per second. While on the other hand, in the case of VDSL, the upstream speed is faster as compared to ADSL, which is about equal to a minimum of 1.5 MB per second to a maximum of 2.5 MB per second.
- The downstream speed in the case of ADSL is slow as compared to the VDSL, which is about a minimum of 500 KB per second to a maximum of 8 MB per second. On the other hand, in the case of VDSL, the downstream speed is faster as compared to ADSL, which is about equal to a minimum of 50 MB per second to a maximum of 55 MB per second.
- The loop reach of ADSL is about 18,000 feet. Whereas the loop reach of VDSL is about 4500 feet.
- The application of ADSL can be for internet access, video on demand (VOD) technique, for data, and high definition TV (HDTV) as well. On the contrary, the application for VDSL is for internet access and data access only.
- The ADSL provides service types for POTS shared lines and data. While on the other hand, the VDSL provides service types for POTS and symmetric data.
Conclusion
ADSL and VDSL are both types of digital subscriber line techniques. VDSL has many advantages over ADSL such as higher upstream speed, higher downstream speed, it supports asymmetric and symmetric data as well, and more.
However, ADSL is used more widely because it covers more distance. Moreover, VDSL is extremely expensive and since it covers a smaller distance as compared to ADSL, its speed also decreases if the distance range increases.