Cisco CCNA Spanning Tree Protocol (STP) Questions and Answers

Question 1

Three switches are connected in a full mesh topology.
SwitchA has a priority of 32768 and MAC address 0000.AAAA.AAAA.
SwitchB has a priority of 28672 and MAC address 0000.BBBB.BBBB.
SwitchC has a priority of 32768 and MAC address 0000.CCCC.CCCC.
Which switch will be elected as the Spanning Tree Protocol (STP) root bridge?

Accepted Answer

SwitchB

Answer

SwitchA

Answer

SwitchC

Answer

The switch with the highest MAC address

Question 2

A network administrator wants to prevent a user-facing access port from causing a Layer 2 loop if another switch is accidentally connected. The desired behavior is for the port to shut down immediately if it receives a BPDU. Which Cisco feature should be configured on this port?

Accepted Answer

BPDU Guard

Answer

Root Guard

Answer

BPDU Filter

Answer

Loop Guard

Question 3

In the context of the original 802.1D Spanning Tree Protocol, which of the following best describes a Root Port?

Accepted Answer

The single port on a non-root switch that has the lowest path cost to the root bridge.

Answer

A port on the Root Bridge that is in the forwarding state.

Answer

The port on any switch that has the fastest link speed.

Answer

Any port that is actively forwarding traffic on a network segment.

Question 4

Rapid Spanning Tree Protocol (RSTP, 802.1w) improves convergence over the original 802.1D standard by modifying port states. Which three 802.1D port states are consolidated into the single 'Discarding' state in RSTP?

Accepted Answer

Disabled, Blocking, and Listening

Answer

Listening, Learning, and Forwarding

Answer

Blocking, Learning, and Forwarding

Answer

Disabled, Listening, and Learning

Question 5

A network topology consists of SwitchA (Root Bridge), SwitchB, and SwitchC. SwitchB connects to SwitchA via a 1 Gbps link. SwitchC connects to SwitchB via a 100 Mbps link. Assuming default STP costs are used, what is the root path cost for SwitchC?

Accepted Answer

23

Answer

4

Answer

19

Answer

38

Question 6

During the standard 802.1D STP convergence process, in which port state does a switch begin to populate its MAC address table but does not yet forward user data frames?

Accepted Answer

Learning

Answer

Forwarding

Answer

Blocking

Answer

Listening