Growth In Internet Speed Systems
Currently, big and small businesses are experiencing explosive growth in the use of all types of data networks. Internet access, for example, is becoming an increasingly important strategic element for all businesses. As their Internet usage increases, and as high-bandwidth applications, such as streaming media, videoconferencing, and e-commerce become more common on the Internet, businesses are running out of bandwidth far earlier than they ever imagined.
At 1.5 Mbps, T1 lines do not have sufficient bandwidth to deal with the new Demands made on networks. Yet fiber-based T3 circuits are overkill for many small and midsized businesses. T3 provides 45-Mbps bandwidth, but it comes at a steep premium because T3 circuits lease for upwards of $4,000 a month, compared to as low as $400 for T1 lines. Moreover, T3 circuits are not easily available to many businesses, while T1 lines are ubiquitous.
The price/bandwidth/availability gap between TI and T3 is sending businesses and service providers alike scrambling for cost-effective ways to fill needs. They are finding that, because until recently there was little demand for bandwidth between T1 and T3, no one has developed a truly effective means to fill the T1-T3 gap.
Several business users expected that digital subscriber line (DSL) technology, cable, wireless, or ATM would solve the gap problem. Keep in mind that bandwidth upstream is lower than bandwidth downstream. Efficiency, or cost, no one technology offers all the characteristics required by business applications.
Symmetric DSL (SDSL), a scalable solution that does a terrific job of filling in the bandwidth gap between 56 kbps and 1.5 Mbps, offers an upgrade path from dial-up modems. While it suffers from availability and standards problems, SDSL is gaining significant momentum in the market.
Asymmetrical DSL (ADSL) is primarily a residential service and is focused on universal ADSL (UADSL), promises to offer speeds up to seven Mbps downstream. However, it suffers from a low upstream speed of only 768 kbps today. In addition, ADSL has very limited deployment. DSL in general also suffers from a lack of standards and from bandwidth variation depending on the location, length, and quality of the copper lines.
Broadband cable offers high speeds but is also highly asymmetrical, and it was developed for residential use. Cable transmissions are shared between multiple users, creating security and availability concerns that make cable a questionable choice for business use.
Wireless technology is used in multitenant facilities, but undertaking an antenna-construction and line-of-site engineering project is far too expensive for the typical individual business subscriber. Wireless can be expensive at the service provider's point of presence (POP) as well, due to the expense associated with separate radio and aggregation equipment. In addition, mere may be security and availability concerns with wireless technology, depending on equipment and installation variations.
ATM, which is preferred by many carriers, is suitable where end-to-end quality of service (QoS) is an important consideration and where the service provider's infrastructure is based on ATM. Use of ATM carries a bandwidth penalty, however, since it assesses a stiff "cell tax" that can reduce the payload of a circuit by 20% to 30%. Consequently, ATM is not an efficient access technology for TCP/IP-based networks, such as the Internet.
