A regional operating unit of New York- based Verizon Communications, Verizon Washington, DC provides telecommunications services to residential and business customers in and around the District of Columbia. Verizon Communications is the second largest US telecom carrier (behind AT&T) and the leading cell phone service provider (ahead of AT&T Mobility). The company provides wireless service, local calling, long-distance, and Internet services. It also offers a wide range of business services such as systems integration and communications network management through its Verizon Business arm. Digital video broadcasting and video-on-demand services are offered over Verizon's fiber-optic network known as FiOS.