ration with Comcast. The Wi-Fi Alliance sets standards for roaming between Wi-Fi access points. Wi-Fi roaming involves middlemen. Intermediaries provide authentication that determines if the device belongs to a legitimate network provider. The intermediary also handles accounting functions related to billing. Wireless Internet Service Providers A Wireless Local-Area Network (Wi-Fi) hotspot is a public area where people with Wi-Fi-equipped laptops, tablet computers, and smartphones can access the Internet. The Wi-Fi hotspot business is multilayered and includes aggregators, cellular providers, and companies that supply back-office services such as billing, roaming, and secure access to corporate networks from hotspots. Hotspot operators are also referred to as Wireless Internet Service Providers (WISPs). The largest hotspot operator in the United States is AT&T Wi-Fi Services (formerly Wayport before AT&T purchased it in 2008). AT&T Wi-Fi Services is an aggregator. Aggregators install hardware and Internet www.TechnicalPDF.com access for hotspot services and resell it to other providers who provide billing, marketing, and customer service to end users. AT&T offers Wi-Fi access directly to its own subscribers as well as on a wholesale basis to other providers. These providers in turn offer it to their own customers. T-Mobile USA also owns an extensive number of hotspots. It offers the service at no charge to its subscribers. SATELLITES- GEOSYNCHRONOUS AND LOW EARTH ORBITING Geosynchronous satellites orbit 22,300 miles above the earth's surface. Because of this distance, each satellite can beam signals to a very large area; therefore, less equipment is required for coverage. This makes satellite service attractive for rural and difficult-to-cable areas. Satellite Networks Satellite networks are composed of a hub, the satellites themselves, and receiving dish antennas. Receiving antennas also are called ground stations. Receivers on antennas convert Radio Frequency (RF) wireless signals to electrical signals. The tra