facilities-based network operator has service everywhere. These operators sell wholesale services as a part of their product strategy. There are companies whose major business strategy is selling capacity on fiber-optic cables they own. These include Consolidated Telecommunications Services, and NEF. www.TechnicalPDF.com An example of a wholesale provider is Level 3 whose main line of business was wholesale services to other telecom companies before it was purchased by CenturyLink. It sold capacity on its interstate long-haul network. Tower builder Crown Castle purchased fiber network provider Lightower and started a wholesale division called Crown Castle Fiber to complement its antenna and tower business. Electric utilities often sell wholesale data network services. Electric utilities own vast fiber networks over which they transmit electrical signals. They also own dark fiber, spare fiber that is not "lit" by fiber equipment. When utilities lay fiber, they lay extra fiber to be prepared for surges in electrical usage or maintenance issues on other fiber strands. Carriers that sell wholesale services save money on marketing, retail stores, billing, and staff. They hope to make up for lower per-user revenues with savings in operating costs and its customers' quantity leases. Depending on the arrangement with each carrier customer, it might also offer handsets and billing platforms to the carrier. Backhaul Services Another way that cable TV operators add services to their existing infrastructure is by leasing spare capacity on their backbone networks to mobile operators. Multiple Service Operators (MSOs) use their backbone networks to link their local cable TV facilities to centralized headends that distribute TV and movies and perform functions such as billing and links to the Internet and other networks. Backhaul services that mobile providers lease link cell sites (towers and antennas) to the data centers that support functions such as security and billing. www.TechnicalPDF.com Large cable TV operators as well