This read-only Counter64 reports the transmit byte rate for this PM instance, sampled per second. Admins compare this to the port's provisioned egress bandwidth in real time to see whether a service is currently saturating its allocation, well before a daily or 24-hour total would reveal it; because it is drawn from the lifetime bin, which keeps accumulating until an operator explicitly clears it, a sudden plateau on an otherwise busy instance is itself a signal — most likely that someone cleared the stats rather than that traffic actually stopped. On a 10 Gbps aggregation trunk carrying multiple EVCs, a live reading of 1,961,734,674 bytes/sec against a 10,000,000,000-bps port tells an admin roughly how close to full the link is running right now.