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The Internet has been influencing enterprises for well over a decade and has changed the way business is communicated and conducted. It’s often the primary channel through which businesses gather information, communicate with customers and interact with suppliers. As the use of the Internet expands and the demand for high-speed access increases, businesses are looking for cost-effective connection options for remote workers, satellite offices and traveling employees. Two leading methods for high-speed access are DSL and cable Internet.
Digital Subscriber Line (DSL) is a family of technologies that supports high-speed transfer of information over the regular telephone network. A DSL signal can share a line with a voice signal; therefore, DSL Internet connections do not tie up the phone line the way dial-up connections can. There are several different “flavors” of DSL, with the most common being Asymmetric DSL (ADSL) and Symmetric DSL (SDSL). SDSL delivers the same speed for both uploads and downloads; whereas, ADSL can download faster than it can upload. Because most users are more likely to download information from the web than upload large amounts of data, ADSL is a good fit for many businesses.
Cable Internet access is a method for delivering data over the coaxial cable networks that were deployed to deliver television signals, primarily to residential customers. Like DSL, it requires a special device at the receiving end, known as a cable modem, and is sometimes called cable modem service. Given its heritage as a residential offering, it’s often sold as an add-on to cable TV. In some locations, cable may not be available as a stand alone service, at least not at competitive prices. However, since it is associated with cable, it is generally widely available.
Which is Faster?
Because they are available at a fraction of the cost of T1 services, both DSL and cable can be a cost effective alternative to more traditional access methods. Speed and cost are two common differentiators between DSL and cable. Other issues that should be considered include installation requirements, security features and customer service.
Both DSL and cable are faster than dial-up, but their speed relative to each other depends on a number of factors. It is difficult to conduct a straight comparison, as each situation may have a different result. There are three main elements that determine data transfer speed:
- DSL is affected by the resistance of copper telephone wires and that resistance can attenuate the signal. Due to this attenuation, DSL achieves faster speeds when the end-point is closer to the telephone company’s central office.
- Cable may offer more bandwidth, which gives it a higher upper speed limit. Unlike DSL, cable is not affected by distance, but performance can be degraded by bandwidth sharing. In a given area, many cable modem users are sharing the same connection, which can lead to latency and bandwidth contention if a large number of cable modem users are simultaneously accessing the Internet.
- Both DSL and cable providers may employ bandwidth caps, setting a maximum speed based on how much bandwidth is appropriate. These caps are designed to help ensure that subscribers receive the service and bandwidth purchased.
As cable’s speed is impacted by a variety of factors, cable’s raw speed advantage is not as dramatic as it appears at first glance. Regardless of the access method, local network and PC performance play a role in the effective speed. More importantly, cable speed varies according to the number of connections serving a particular geography, the number of users per connection, the number of users who are actually connected at a given time and the functions users are performing. Due to these variations, cable may not be as predictable or as consistent as DSL. The speed and performance of cable Internet access may fluctuate during a typical business day, which can be very frustrating to end users who need more consistent performance.
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