csOc3PathDayUASs is a read-only PerfCurrentCount counter reporting the number of Unavailable Seconds — seconds counted once ten consecutive severely errored seconds occur at the Path layer — that the SONET/SDH Path layer of this OC3 port has recorded accumulated so far today. A rising count here is the operational signal that an extended outage of the OC3 path is happening on that interface, which is exactly the kind of degradation a monitoring admin wants an early warning of before it causes an outage. For example, checking csOc3PathDayUASs mid-afternoon and finding it already well above a typical day's baseline is an early sign of an extended outage of the OC3 path on the SONET/SDH Path layer of this OC3 port, well before the day's tally is complete.