This read-write INTEGER (0-100) sets the error-rate percentage above which this port automatically falls back from cut-through to the more error-tolerant store-and-forward mode, working as the upper bound of a hysteresis pair with ciscoTsPortCfgErrLoThreshold. This protects the network from a degrading link flooding it with partially-corrupted frames at wire speed, once errors cross this line, the switch starts buffering and checking each frame fully before forwarding it. An admin might set this to 10, so a port with more than 10% observed error rate reverts to the safer mode until conditions improve.