> # Bit Error Thresholds

> The bit error rate threshold is used by the switch to detect an increased error rate before performance degradation seriously affects traffic.

> The bit errors can occur for the following reasons:

> - Faulty or bad cable.
> - Faulty or bad GBIC or SFP.
> - GBIC or SFP is specified to operate at 1 Gbps but is used at 2 Gbps.
> - GBIC or SFP is specified to operate at 2 Gbps but is used at 4 Gbps.
> - Short haul cable is used for long haul or long haul cable is used for short haul.
> - Momentary sync loss.
> - Loose cable connection at one or both ends.
> - Improper GBIC or SFP connection at one or both ends.

> A bit error rate threshold is detected when 15 error bursts occur in a 5-minute period. By default, the switch disables the interface when the threshold is reached. You can enter a shutdown and no shutdown command sequence to re-enable the interface.

> You can configure the switch to not disable an interface when the threshold is crossed. By default, the threshold disables the interface.

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