STP Network Design and Implementation 2

Question 1

In a redundant network design, which STP feature allows ports to bypass the Listening and Learning states and go directly to Forwarding?

Accepted Answer

PortFast

Answer

PortFast skips the Listening and Learning states, allowing a port to transition immediately to Forwarding — intended for access ports connected to end devices.

Question 2

A network engineer is designing a campus network with three distribution switches. Which STP enhancement should be deployed to ensure only designated root bridges can exist in specific VLANs?

Accepted Answer

Root Guard

Answer

Root Guard enforces the root bridge placement by blocking ports that receive superior BPDUs, preventing unexpected switches from becoming the root.

Question 3

Which topology creates the highest risk of STP failure due to unidirectional link failures?

Accepted Answer

Fiber optic links without Loop Guard

Answer

Fiber optic links can fail in one direction only (receive or transmit), causing STP to not detect the failure; Loop Guard mitigates this by moving the port to a loop-inconsistent state.

Question 4

In a hierarchical three-tier network design, where should the STP root bridge ideally be placed?

Accepted Answer

Core layer

Answer

Placing the root bridge at the core layer ensures that traffic flows optimally from access to distribution to core, avoiding suboptimal paths.

Question 5

A switch receives a BPDU on a PortFast-enabled port. If BPDU Guard is also enabled globally, what happens?

Accepted Answer

The port is placed in errdisable state

Answer

BPDU Guard shuts down the port (errdisable) immediately upon receiving any BPDU, protecting the network from rogue switches on access ports.

(STP) Spanning Tree Protocol Practice Test

(STP) Spanning Tree Protocol Practice Test

STP Network Design and Implementation 2