csDs3StatTotalLSESs is a read-only PerfTotalCount counter reporting the number of Line Severely Errored Seconds — a one-second period with a heavy burst of line bipolar violations — that this unchannelized DS3/E3 physical line has recorded summed across the entire previous 24-hour period, with any invalid 15-minute bucket counted as zero. (this counter applies to both DS3 and E3 line types) A rising count here is the operational signal that a badly degraded copper/coax DS3 or E3 line, connector, or repeater 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, comparing csDs3StatTotalLSESs's 24-hour rollup from one night to the next lets an admin judge whether a badly degraded copper/coax DS3 or E3 line, connector, or repeater on this unchannelized DS3/E3 physical line is a one-off blip or a worsening trend.