Abstract: In a passive optical network (PON), multiple optical network terminals (ONTS) transmit data to an optical line terminal (OLT) using a common optical wavelength and fiber optical media. Various components of the PON, including the OLT and ONT(s), can malfunction. Centralized techniques for maintaining or diagnosing fault conditions may be ineffective in large networks or in relatively small networks because of vast amounts of information and limited storage capacity for the information. Thus, fault conditions may occur and not be diagnosed due to lost or overwritten information. Therefore, a distributed approach based on information related to ranging of ONTs within the PON is employed in an example embodiment of the invention. This distributed approach can improve monitoring and diagnosis of fault conditions that may lead to instability of the PON.