Aspects of the present disclosure aim at configuring an optical time domain reflectometry (OTDR) in a central office such that the OTDR is configured to be operatively coupled with and also configured to periodically poll each fiber at defined intervals and compute/store a reflection signature that can be used to compare with future signatures received from subsequent polls of the fiber to determine a fault (e.g., a fiber cut or breakage) between the central office (CO) and one or more optical network unit (ONU) over GIS.