200-301 Question 214
Single answerYou are configuring a switched network with multiple VLANs. During STP operation, you notice that Switch A has been elected as the root bridge. On Switch B, you see the following port roles: one port is labeled as the Root Port (RP), and another port is labeled as Designated Port (DP). What is the role of the Root Port on Switch B?
- A
The Root Port is the port with the lowest port ID on Switch B.
- B
The Root Port is the port with the lowest path cost to the root bridge.
- C
The Root Port is the port that has been manually configured to forward traffic to the root bridge.
- D
The Root Port is the port that forwards traffic to downstream switches.
Show answer and explanation
Correct answer: B
Explanation
In Spanning Tree Protocol (STP), the Root Port (RP) is the port on a non-root switch that has the lowest path cost to the root bridge. This port is used to forward traffic towards the root bridge, ensuring the most efficient path in the network. The selection of the Root Port is automatic and based on STP's path cost calculations, not manual configuration or port ID.
- A. Incorrect.
This is incorrect. The Root Port is not determined by the port ID, but by the path cost to the root bridge.
- B. Correct.
This is correct. The Root Port on a switch is the port with the lowest path cost to the root bridge, ensuring the most efficient path for communication.
- C. Incorrect.
This is incorrect. Root Ports are not manually configured; they are selected based on STP calculations, specifically the lowest path cost to the root bridge.
- D. Incorrect.
This is incorrect. A Root Port forwards traffic towards the root bridge, not downstream switches. Traffic to downstream switches is handled by Designated Ports.