 way to lower the cost of selling services to small businesses. Today many agents sell telephone services as an adjunct to the telephone and networking equipment that they offer. Agents are certified and receive some training from the telephone and cable TV companies they represent. They do not bill customers directly for the voice and data services they sell; rather, customers receive bills directly from the carriers. Primarily small and medium-sized organizations use agents because they are often easier to reach, and some have the ability to help troubleshoot problems when it is not apparent whether the problem is in the carrier's connections or the onsite equipment. Moreover, carriers often prefer to serve smaller business customers with agents to reduce their own staffing and selling expenses. Retail outlets such as Best Buy and Staples act as agents for cellular providers and prepaid cellular services as do small retail outlets in shopping districts and malls. Wal-Mart, Target, and Amazon sell TracFone Wireless's prepaid mobile phones and services. TracFone Wireless is a unit of Mexico's TelMex. In addition to large retailers, there are often networks of small retailers that act as agents for larger companies such as Comcast, T- Mobile, Sprint, and Verizon Wireless. The small retailers display the logos of the carriers that they represent in their stores and sell hardware and accessories for mobile phones in addition to service plans. Resellers-Mobile Virtual Network Operators www.TechnicalPDF.com Like agents, resellers do not own network infrastructure. Resellers are also referred as Mobile Virtual Network Operators (MVNOs). Unlike agents, however, resellers provide billing and customer service for their customers and market services under their own brand. Resellers sell wireline service such as data (Gigabit Ethernet and other high-speed services), calling cards, Internet access, local calling, long-distance, mobile services, VoIP services, and international calling. Table 3-7 lists a sampling of resellers