| A | B |
|---|
| BPDU Filter | an STP feature that filters BPDUs from being advertised/received acress the configured port |
| BPDU guard | An STP feature that places a port into an ErrDisabled state if a BPDU is received on a portfast-enabled port. |
| root guard | An STP feature that places a port into an ErrDisabled state if a superior BPDU is received on the configured port. |
| STP portfast | An STP feature that places a switch port directly into a forwarding state and disables TCN generation for a change in link state. |
| STP loopguard | An STP feature that prevents a configured alternative or root port from becoming a designated port toward a downstream switch. |
| Unidirectional Link Detection (UDLD) | A protocol that provides bidirectional monitoring of fiber-optic cables. |
