This attribute indicates the total number of one second intervals for which the DS3 path is unavailable. The DS3 path becomes unavailable at the onset of 10 consecutive Path Severely Errored Seconds (PSES). The 10 PSESs are included in the unavailable time. Once unavailable, the DS3 path becomes available at the onset of 10 contiguous seconds with no PSES. The 10 seconds with no PSES are excluded from the unavailable time. For second intervals where PUAS is counted, counting of Path Coding Violations (PCV), Path Errored Seconds (PES), Path Severely Errored Seconds (PSES) and Path Sef/Ais Seconds (PSAS) is inhibited.