Which option is not an RSTP port state?
- learning
- blocking
- discarding
- forwarding
Explanation: In the evolution from the original 802.1D Spanning Tree Protocol (STP) to the 802.1w Rapid Spanning Tree Protocol (RSTP), the number of port states was reduced and simplified to allow for faster convergence. While traditional STP utilizes five distinct states—disabled, blocking, listening, learning, and forwarding—RSTP consolidates the first three into a single state known as discarding. In the discarding state, the port does not forward user data or learn MAC addresses, though it can still process BPDUs. The learning and forwarding states remain functionally similar across both versions of the protocol. Because the functionalities of the old blocking and listening states are now merged into discarding, "blocking" is technically no longer a valid port state in an RSTP-enabled environment.
Related exam: Modules 1 – 7: Checkpoint Exam: Network Switching Answers (CCNP ENCOR v9)
