This Counter64 counts the number of times the R-bit (remote fault indicator) was set in packets received for this pseudowire, meaning the far-end pseudowire endpoint signaled that it detected a fault on its own local TDM interface. Because this is the cumulative TdmPwTotalStatistics counter for the pseudowire, tallied since the bin's own start time rather than being reset every short collection interval, a rising Rbit count (with Lbit staying low) tells you the trouble is on the far end of this circuit, not on this device, which changes where you would send a technician. For example, Rbit incrementing steadily while Lbit stays at zero on this device points investigation toward the remote site's TDM equipment rather than anything local.