This read-only PerfTotalCount reports the count of frames discarded because of receiver overruns on the DSL port, scoped to one specific 15-minute bucket out of the 96 stored for that DSL port. Operationally, overruns mean the receive buffer filled up faster than frames could be processed, causing outright data loss. For example, an admin correlating an overrun spike in a specific 15-minute bucket with a traffic-monitoring graph can confirm whether a burst of customer traffic overwhelmed the receiver at that exact time.