BCMSN Exam Cram™ 2 (Exam Cram 642-811)

Summary

PortFast, UplinkFast, and BackboneFast are Cisco proprietary STP enhancement features. All are disabled by default. PortFast keeps a port in forwarding mode, where it is not included in the STP algorithm. Nonswitch and nonbridge devices should be connected to PortFast ports. To enable PortFast, use the spanning-tree portfast interface command. To prevent inadvertent switch connections to PortFast ports, you can use the BPDU Guard and filter features. BPDU Guard shuts down a PortFast port if a BPDU is received on it. If BPDU filtering detects more than 10 BPDUs on a port, it disables PortFast on the port and treats it as a normal STP port.

UplinkFast provides fast convergence for uplink ports. If the root port fails, a secondary uplink ...