8.8 Connecting to the Internet
8.8.7 Cable modem versus DSL Internet technologies
When it comes to comparing cable modem and DSL Internet technologies, both have their pros and cons. DSL service can be added incrementally in an area. This means that the service provider can literally start up with a handful of clients and upgrade the bandwidth to coincide with the growth in subscriber numbers. DSL is also backward compatible with analog voice and makes good use of the existing local loop. This means that very little needs to be done to use the cable service simultaneously with normal phone service. However, DSL suffers from distance limitations. Most DSL service offerings currently require the customer to be within 18,000 feet of the provider's Central Office (CO) location. Additionally, the longer and older loops present problems, and the best form of voice support is still being debated. Also, the upstream (upload) speed is usually considerably lower than the downstream (download) speed.

In contrast, cable modem technology presents plenty of relatively inexpensive bandwidth. In fact, the downstream and upstream Internet channels are seen as just another premium TV channel by the system. This is a major advantage, especially when hosting a web server or a FTP server, which involves upload-intensive Internet tasks. The use of fiber (hybrid-fiber-coax or HFC) greatly addresses some of the service shortcomings that are initially encountered with this technology. Unfortunately, the cabling infrastructure that is needed to support cable modem technology has been slow to be upgraded thus most homes in the United States cannot use this technology. Upgrading is a big investment, particularly for small providers.

The advantages and disadvantages of these two Internet technologies are summarized in Figures and .