ISTRAC is ISRO's telemetry and tracking network. Do you know what telemetry is ? It is the science and technology of automatic measurement and transmission of data by wire, radio, or other means from remote sources. ISTRAC is responsible for providing space operation services like spacecraft control. These services are provided for the launch vehicle and low orbiting spacecrafts, as well as for the deep space missions of both ISRO and other space agencies around the world.
Over the years, ISRO has established a network of tracking stations to provide the necessary telemetry and tracking support for missions in space. These stations are of international standards, and are located at Bangalore, Lucknow, Sriharikota, Thiruvananthapuram, port Blair Island, Brunei, Biak, and maurtius. ISTRAC has its headquarters at Bangalore.