200-301 Question 217
Single answerYou are troubleshooting a spanning-tree issue in a network. Switch A has been elected as the root bridge. On Switch B, you notice that one of its ports, Gi0/1, is in a forwarding state and is directly connected to Switch A. Which port role is assigned to Gi0/1 on Switch B?
- A
Root Port
- B
Designated Port
- C
Blocked Port
- D
Alternate Port
Show answer and explanation
Correct answer: A
Explanation
In a spanning-tree topology, the Root Port is the port on a non-root switch that has the lowest cost path to the root bridge and is in the forwarding state. Since Gi0/1 is directly connected to the root bridge (Switch A) and is forwarding traffic, it fulfills the role of a Root Port.
- A. Correct.
Correct. A Root Port is the port on a non-root switch that has the lowest cost path to the root bridge. Since Gi0/1 is directly connected to the root bridge (Switch A) and is in the forwarding state, it is the Root Port for Switch B.
- B. Incorrect.
Incorrect. A Designated Port is the port on a segment that has the lowest path cost to the root bridge, but this role applies to a port on the same segment as the Root Port, not directly connected to the root bridge.
- C. Incorrect.
Incorrect. A Blocked Port is a port that does not forward traffic to prevent loops. Since Gi0/1 is in the forwarding state, it cannot be a Blocked Port.
- D. Incorrect.
Incorrect. An Alternate Port is a port that provides backup connectivity to the root bridge and remains in a discarding or blocking state. Gi0/1 is in the forwarding state, so it cannot be an Alternate Port.