Identifying the STP Mode on a Catalyst Switch

Cisco Catalyst switches support an STP mode, as configured with the spanning-tree mode global configuration command. Based on this command’s setting, the switch is either using 802.1D STP or 802.1w RSTP, as noted in Table B-4.

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Table B-4 Cisco Catalyst STP Configuration Modes

To determine whether a Cisco Catalyst switch uses RSTP, you can look for two types of information. First, you can look at the configuration, as noted in the left column of the table. Also, some show commands list the STP protocol ...

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