are another example of sites that require middle-mile connections. These data centers generate large amounts of traffic for which they require high-speed connections on middle-mile networks to backbone POPs. Large carriers such as Verizon and AT&T in the United States carry the majority of middle-mile traffic. Level 3 Communications (now part of CenturyLink) is an alternative option in some areas. Level 3 offers to connect rural areas to POPs using spare capacity in its regional and long-haul networks. In the newer networks of these providers, hubs with Gigabit Ethernet switches are able to add and drop off traffic. Connections to Gigabit Ethernet are less costly than those to older SONET facilities. However, they require costly fiber cabling or wireless infrastructure from the rural provider's first-mile network to the middle-mile network switch. Because of the low population densities in rural areas that do not generate adequate revenue, this is not always financially feasible. The High Cost of Rural Internet Connectivity High-speed middle-mile connectivity is a major challenge in rural and sparsely populated areas worldwide. Although there are a growing number of fixed-wireless Internet access options, a majority of providers in these areas offer Internet access-predominately on Digital Subscriber Line (DSL) service-with some providing cable modems (see Chapter 5 for a more in-depth www.TechnicalPDF.com description of DSL service). The high costs of laying fiber or high-speed wireless connections to reach a broadband carrier for transport are passed on to customers and result in high end-user prices for cable TV and Internet access. The National Exchange Carrier Association (NECA) is a nonprofit association of small, rural carriers that was formed by the Federal Communications Commission (FCC) to administer access charges. Access charges are the fees long-distance companies pay to access the networks of the 1,049 small rural local phone companies to complete their long-distance customers' calls. In its publica