STP and Loop Prevention Concepts

1. In STP, which device is responsible for sending Bridge Protocol Data Units (BPDUs)?

Root bridge only

All switches in the spanning tree domain

Access layer switches only

The network gateway

2. In STP, the ______ is the switch with the lowest bridge ID and serves as the reference point for the topology.

Root bridge

Primary switch

Core switch

Distribution switch

3. What is the primary advantage of RSTP over traditional 802.1D STP?

Lower cost to implement

Faster convergence and rapid state transitions

Support for more VLANs

Elimination of the root bridge requirement

4. In STP, which port state does not forward data frames but listens for BPDUs?

Forwarding

Learning

Listening

Blocking

5. What happens to MAC address tables when a switching loop exists without STP?

They become static and never update

They become unstable due to constant frame flooding

They are cleared every second

They are not affected by loops

6. In a switched network, a switching loop occurs when there are ______ between switches without STP enabled.

Single paths

Redundant paths

Blocked ports

Root ports

7. STP uses the concept of ______ to determine the best path to the root bridge.

Hop count

Metric

Cost

Weight

8. In RSTP, what is the maximum age timer value used to discard BPDUs?

10 seconds

15 seconds

20 seconds

30 seconds

9. What is the default Hello Time interval for STP BPDU transmission?

1 second

2 seconds

5 seconds

10 seconds

10. Which STP port state allows a port to forward data frames while still listening for BPDUs?

Blocking

Listening

Learning

Forwarding

11. What is the default bridge priority value in IEEE 802.1D STP?

0

32768

65535

128

12. What is the primary purpose of Spanning Tree Protocol in a switched network?

Prevent switching loops by blocking redundant paths

Increase bandwidth across all switch ports

Assign IP addresses to network devices

Enable VLAN routing between switches

13. What is the root port in a spanning tree topology?

The port that connects directly to the root bridge

The lowest-cost port to reach the root bridge

Any port on a non-root switch

A port that is always in forwarding state

14. Which timer determines how long a switch waits after entering the learning state before transitioning to forwarding?

Hello Time

Forward Delay

Max Age

Message Age

15. In STP, a port transitions through which state before entering the forwarding state?

Blocking, listening, learning, forwarding

Listening, blocking, forwarding

Learning, listening, forwarding

Disabled, learning, forwarding

16. How many port roles exist in Rapid Spanning Tree Protocol (RSTP)?

2

3

4

5

17. Which STP port role is responsible for forwarding frames toward the root bridge?

Designated port

Root port

Backup port

Alternate port

18. What is the primary difference between a designated port and an alternate port in RSTP?

Designated ports forward frames; alternate ports are blocked

Alternate ports have lower cost than designated ports

Designated ports are only on non-root switches

Alternate ports are used for backup redundancy only

19. Which STP variant supports multiple spanning trees per VLAN?

802.1D STP

RSTP

MSTP

PVST

20. RSTP improves convergence time by using ______ to detect link failures instead of waiting for timers.

Hello messages

Link status notifications

BPDUs with specific flags

Port cost adjustments

Network+ Spanning Tree Protocol and Loop Prevention Quiz