Very High-Speed Digital Subscriber Line (VDSL)
It was only matter of time until some users demanded higher speed communications than was offered by the current DSL technologies.
VDSL was introduced to achieve the higher speeds. In fact, speeds ranging from 13 to 52 Mbps are available, but the distance limitations of the local cable will be a big factor.
In order to achieve the speeds, one can expect that a fiber feed will be used to deliver VDSL. This technique will most likely carry ATM (cells) as its primary payload.
We can expect some hybrid arrangements to deliver this speed to the door for high-speed data at up to 52 Mbps downward and 1.5 to 6 Mbps upward.
These are the typical installation and operational characteristics; others will certainly exist in variations of installation and implementation.
Service |
Explanation |
Download |
Upload |
Mode of Operation |
ADSL |
Asymmetric DSL |
1.5 - 8.192 Mbps |
16 - 640 Kbps |
Different up and down speeds;one pair of wire |
RADSL |
Rate-adaptive DSL |
64Kbps - 8.192 Mbps |
16 - 768 Kbps |
Different up and down speeds;many common operations on 768 Kbps. |
CDSL |
Consumer DSL |
1 Mbps |
16 - 128 Kbps |
Now ratified as DSL-lite. |
HDSL |
High-bit-rate DSL |
1.544 Mbps in North America; 2.048 Mbps in the rest of theworld |
1.544 Mbps 2.048 Mbps |
Symmetrical services |
IDSL |
ISDN DSL |
144 Kbps |
144Kbps |
Symmetrical operation. |
SDSL |
Single DSL |
1.544 Mbps 2.048 Mbps |
1.544 Mbps 2.048 Mbps |
Uses only one pair, but typicallyprovisioned at 768 Kbps. One pair of wire. |
SHDSL |
Single-pair high-bit-rate DSL |
2.312 Mbps |
192 - 384 Kbps |
Uses one pair, aimed at smallresidential customers |
VDSL |
Very high-speed DSL |
13 - 52 6 Mbps |
1.5 - 6.0 Mbps |
Fiber needed and ATM probably used |
This introduction is meant to teach you about the functions and technology of DSL.