Configuration and Management Flashcards

Which STP feature automatically sets an access port to forwarding state immediately without going through listening and learning?

Answer: PortFast

PortFast bypasses the listening and learning states and immediately transitions an access port to forwarding, reducing convergence time for end devices.

What command enables PortFast on all non-trunking access ports globally on a Cisco switch?

Answer: spanning-tree portfast default

The global command 'spanning-tree portfast default' enables PortFast on all non-trunking interfaces without configuring each one individually.

Root Guard is best applied to which type of port?

Answer: Designated ports where unauthorized root bridges might appear

Root Guard is applied to designated ports to prevent a connected switch from becoming the root bridge by placing the port in root-inconsistent state if a superior BPDU is received.

What does the 'spanning-tree loopguard default' command do?

Answer: Enables Loop Guard globally on all point-to-point ports

The 'spanning-tree loopguard default' command globally enables Loop Guard on all point-to-point ports, protecting against unidirectional link failures.

Which STP timer controls how long a port remains in the listening and learning states?

Answer: Forward delay

Forward delay (default 15 seconds) is the time a port spends in each of the listening and learning states before transitioning to forwarding.

What is the effect of reducing the STP max-age timer below its default of 20 seconds?

Answer: Switches declare a root bridge failure more quickly, speeding up convergence

Reducing max-age causes switches to declare stale BPDU information invalid sooner, speeding up failure detection and convergence.

Which command displays a summary of the number of STP instances and port states on a Cisco switch?

Answer: show spanning-tree summary

The 'show spanning-tree summary' command provides a concise overview of all active STP instances and the count of ports in each state.