DSL is a relatively new Wide Area Network (WAN) connection method in comparison to technologies such as X.25, Frame Relay, and ISDN. If you are a home broadband user, chances are you may have DSL. It is one of the most popular WAN technologies for home users.
In 1925 Bell Labs started to explore ways to use traditional copper phone wires to transmit more than just voice traffic. By 1940 researchers had found a way to connect a teletypewriter in New Hampshire with a computer in New York (Bell Labs). Bell Labs continued with their research and by the late 1980's Digital Subscriber Lines (DSL) technology was invented.
DSL works via the same copper phone lines that regular telephones use. These are often referred to as Plain Old Telephone Service (POTS) lines. The pair of copper wires that come into your home are capable of handling more bandwidth and a greater range of frequencies than required by voice conversations alone. Therefore they can be used for simultaneous voice and data transmission. This is achieved by splitting the frequencies or using filters. Therefore DSL can transmit digital signals on higher frequencies, while not interfering with voice conversations.
There are two basic types of DSL technology: asymmetric and symmetric. Asymmetric DSL assumes the user needs more bandwidth to download, rather than upload, so therefore splits up the bandwidth accordingly. Asymmetric DSL is what the majority of residential users have. Symmetric DSL, on the other hand, provides the same upload and download speeds. This type of DSL is often found in small businesses that require greater upload capacity for file and data transfers than home users do.
DSL offers many advantages over other WAN technologies. For home users it offers a cheap and easy method of acquiring broadband internet. There is usually no or very little additional costs associated with hardware installation since DSL uses existing phone wires and providers will often supply the modem and filters as part of the service. With DSL you can use your phone line and internet connection simultaneously, a feature that is not possible with a regular dial-up modem. Furthermore, DSL offers an always-on connection, and some providers allow unlimited data transfers.
Despite the many highlights of DSL technology, it does have some drawbacks. One of its biggest downfalls is that of distance limitation. The subscriber must live within close distance of the provider. The further one lives away, the lesser the chance of even acquiring a connection so therefore DSL providers check the distance of the line before setting up the service.
DSL is capable of reaching download speeds beyond that of a T1 (1.544 Mbps). In fact there are many DSL providers in the United Kingdom who are offering an 8 Mbps service. This puts DSL in competition with Cable as far as speed is concerned. Some may even argue that DSL is faster since Cable is based on shared bandwidth, whereas a DSL connection is not shared between other users in the neighborhood.
|
Featured guides RSS Feed