STP Configuration and Management

Question 1

What STP parameter can be adjusted to influence which switch becomes the Root Bridge?

Accepted Answer

Bridge Priority

Answer

The Bridge Priority is a configurable value within a switch's Bridge ID, which is used to determine the Root Bridge. A lower bridge priority value increases the likelihood of a switch becoming the Root Bridge. Network administrators can manually adjust this value to influence the Root Bridge election and optimize network traffic flow according to their design.

Question 2

What is the effect of configuring PortFast on a switch port?

Accepted Answer

It allows the port to transition immediately to the Forwarding state

Answer

PortFast is an STP feature designed for access ports connected to end devices (like workstations or servers), not other switches. When enabled, PortFast allows the port to bypass the Listening and Learning states and immediately transition to the Forwarding state. This significantly reduces the time end devices wait to connect to the network, improving user experience.

Question 3

Which STP variant is designed to provide faster convergence compared to traditional STP?

Accepted Answer

Rapid Spanning Tree Protocol (RSTP)

Answer

Rapid Spanning Tree Protocol (RSTP) is an evolution of traditional STP designed to provide much faster convergence times. It achieves this by introducing new port roles and states, and by actively negotiating port roles with neighboring switches. This allows for quicker recovery from link failures and topology changes, minimizing network downtime and improving network resilience.

Question 4

How can you verify the current STP configuration and status on a Cisco switch?

Accepted Answer

Use the show spanning-tree command

Answer

On Cisco switches, the `show spanning-tree` command is the primary tool for verifying the STP configuration and operational status. It displays information such as the Root Bridge, bridge priorities, port roles (Root, Designated, Blocking), port states (Forwarding, Learning, Blocking), and port costs for all VLANs. This command is essential for troubleshooting and monitoring STP in a network.

Question 5

What is the purpose of configuring a port’s cost in STP?

Accepted Answer

To determine the path preference and loop prevention

Answer

Port cost is an STP parameter that represents the 'cost' of sending data out of a specific port. Switches use port costs to calculate the shortest path to the Root Bridge and to determine which redundant links should be blocked to prevent loops. Lower cost paths are preferred, allowing administrators to influence traffic flow and ensure optimal network performance and redundancy.

(STP) Spanning Tree Protocol Practice Test

(STP) Spanning Tree Protocol Practice Test

STP Configuration and Management