Question:
Which two spanning-tree port states does RSTP combine to allow faster convergence? (Choose two.)
- blocking
- listening
- learning
- forwarding
- discarding
Explanation: There are only three port states left in RSTP that correspond to the three possible operational states. The 802.1D blocking, and listening states are merged into the 802.1w discarding state.
* Discarding – the port does not forward frames, process received frames, or learn MAC addresses – but it does listen for BPDUs (like the STP blocking state)
* Learning – receives and transmits BPDUs and learns MAC addresses but does not yet forward frames (same as STP).
* Forwarding – receives and sends data, normal operation, learns MAC address, receives and transmits BPDUs (same as STP).
STP State (802.1d) | RSTP State (802.1w) |
Blocking | Discarding |
Listening | Discarding |
Learning | Learning |
Forwarding | Forwarding |
Although the learning state is also used in RSTP but it only takes place for a short time as compared to STP. RSTP converges with all ports either in forwarding state or discarding state.
Exam with this question: CCNA v3.0 (200-125) Study Guide – Exam Dumps
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