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 C-Bit Severely Errored
Seconds (CSES). The 10 CSESs are included in the unavailable
time. Once unavailable, the DS3 path becomes available at the onset
of 10 contiguous seconds with no CSES. The 10 seconds with no
CSES are excluded from the unavailable time. For second intervals
where CUAS is counted, counting of C-Bit Coding Violations
(CCV), C-Bit Errored Seconds (CES) and C-Bit Severely Errored
Seconds (CSES) is inhibited.