sentences:  Airtel's equipment is provided and maintained by Ericsson, Huawei, and Nokia Networks whereas IT support is provided by Amdocs.The transmission towers are maintained by subsidiaries and joint venture companies of Bharti including Bharti Infratel and Indus Towers in India.Ericsson agreed for the first time to be paid by the minute for installation and maintenance of their equipment rather than being paid up front, which allowed Airtel to provide low call rates of /minute.