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JNCIS-ENT Exam - Question 31


In RSTP, which three port roles are associated with the discarding state? (Choose three.)

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Correct Answer: BCD

In RSTP (Rapid Spanning Tree Protocol), the three port roles associated with the discarding state are backup, alternate, and disabled. The discarding state is a state where the port does not forward frames and does not learn MAC addresses. A backup port provides a redundant pathway to the same segment, an alternate port offers a different path to the root bridge, and a disabled port is administratively shut down.

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Tvoja_mtOptions: BCD
Nov 22, 2024

I agree

sandaruwann654Options: BCD
Nov 24, 2024

B,C,D are correct

calvaradofOptions: BCD
Apr 30, 2025

Alternate port—A port that provides an alternate path toward the root bridge if the root port fails and is placed in the discarding state. This port is not part of the active spanning tree, but if the root port fails, the alternate port immediately takes over. Backup port—A port that provides a backup path toward the leaves of the spanning tree if a designated port fails and is placed in the discarding state. A backup port can exist only where two or more bridge ports connect to the same LAN for which the bridge serves as the designated bridge. A backup port for a designated port immediately takes over if the port fails. Disabled port—The port is not part of the active spanning tree. https://www.juniper.net/documentation/us/en/software/junos/stp-l2/topics/topic-map/spanning-tree-overview.html