This read-only PerfTotalCount reports the count of valid frames successfully received on the DSL port, scoped to the DSL port's current, still-accumulating measurement period (not yet rolled into the interval history). Operationally, it's the baseline throughput indicator for inbound traffic, so a healthy line should keep accumulating this steadily under load. For example, an admin comparing successive live polls of this counter can estimate the port's current throughput in frames per second while a test is underway.