A method comprising: - receiving , from a network node and by a metric device, a given communications measurement of a maintenance entity, ME, that includes the network node, wherein the ME includes two network nodes; - associating to the given communication measurement of the ME an availability indicator, wherein the availability indicator corresponds to an availability of the ME at the time the given communications measurement is received; - storing , by the metric device, the given communications measurement in a measurement database, wherein the stored given communications measurement is correlated with a maintenance entity group, MEG, identifier received with the given communications measurement and an ME identifier received with the given communications measurement, wherein an MEG includes multiple MEs; - correlating , by the metric device, the stored given communications measurement with one or more previously received communications measurements, wherein each previously received communications measurement is associated with the availability indicator corresponding to the availability of the ME at a time the particular communications measurement was obtained; - determining , based on availability indicators of consecutive communications measurements for the ME, an availability of the ME during a given time interval, wherein the availability indicators associated with the communications measurements are stored in the measurement database; - changing , by the metric device and in the measurement database, availability indicators of at least one of the one or more previously received communications measurements after the ME has been determined to be unavailable during the given time interval; and - providing , by the metric device, a report indicating the unavailability of the ME after the ME has been determined to be unavailable during the given time interval. - receiving , from a network node and by a metric device, a given communications measurement of a maintenance entity, ME, that includes the network node, wherein the ME includes two network nodes; - associating to the given communication measurement of the ME an availability indicator, wherein the availability indicator corresponds to an availability of the ME at the time the given communications measurement is received; - storing , by the metric device, the given communications measurement in a measurement database, wherein the stored given communications measurement is correlated with a maintenance entity group, MEG, identifier received with the given communications measurement and an ME identifier received with the given communications measurement, wherein an MEG includes multiple MEs; - correlating , by the metric device, the stored given communications measurement with one or more previously received communications measurements, wherein each previously received communications measurement is associated with the availability indicator corresponding to the availability of the ME at a time the particular communications measurement was obtained; - determining , based on availability indicators of consecutive communications measurements for the ME, an availability of the ME during a given time interval, wherein the availability indicators associated with the communications measurements are stored in the measurement database; - changing , by the metric device and in the measurement database, availability indicators of at least one of the one or more previously received communications measurements after the ME has been determined to be unavailable during the given time interval; and - providing , by the metric device, a report indicating the unavailability of the ME after the ME has been determined to be unavailable during the given time interval. <EOS>