Spanning Tree Protocol (STP) Flashcards
7 cards from real ICND1 practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Spanning Tree Protocol (STP) flashcards as text
What is the primary purpose of Spanning Tree Protocol (STP)?
Answer: To prevent switching loops in Layer 2 networks
STP prevents Layer 2 switching loops by placing redundant ports in a blocking state, stopping broadcast storms.
Which IEEE standard defines the original Spanning Tree Protocol?
Answer: IEEE 802.1D
IEEE 802.1D defines the original STP specification; 802.1W defines RSTP and 802.1Q defines VLANs.
What is the default bridge priority value used by Cisco switches in STP?
Answer: 32768
Cisco switches default to a bridge priority of 32768, which is the midpoint of the valid range and must be a multiple of 4096.
In STP, which port state actively forwards user traffic and learns MAC addresses?
Answer: Forwarding
Only the Forwarding state allows a port to send and receive data traffic; it is the final stable active state.
How is the Root Bridge elected in an STP topology?
Answer: The switch with the lowest Bridge ID wins
The switch with the lowest Bridge ID (priority + MAC address) wins the Root Bridge election.
Which STP port state immediately follows the Listening state in the port state transition?
Answer: Learning
After Listening, a port transitions to Learning, where it builds the MAC address table but does not yet forward user traffic.
What is the default STP Hello timer interval at which the Root Bridge sends BPDUs?
Answer: 2 seconds
The Hello timer defaults to 2 seconds, defining how frequently the Root Bridge multicasts Bridge Protocol Data Units to neighbors.