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Spanning-tree mode command

As explained in Acing the CCNA Exam: Volume 1 Fundamentals and Protocols

The spanning-tree mode command is a Cisco IOS global-configuration command that selects the spanning-tree mode used by a switch.

The spanning-tree mode command is used in global configuration mode to select whether a Cisco switch runs PVST+ or Rapid PVST+. The choice matters because both create a separate spanning-tree instance for each VLAN, while Rapid PVST+ provides faster convergence. section 15.1

Enable Rapid PVST+ and verify it

SW1(config)# spanning-tree mode rapid-pvst SW1(config)# do show spanning-tree VLAN0001 Spanning tree enabled protocol rstp The command enables Rapid PVST+. Verification displays rstp, even though the configured keyword is rapid-pvst. section 15.1

Use show spanning-tree to identify the active mode: protocol ieee indicates PVST+, whereas protocol rstp indicates Rapid PVST+. The default depends on the switch model and IOS version. section 15.5

How Acing the CCNA Exam: Volume 1 Fundamentals and Protocols covers it

How deep it goes
Explains syntax, mode effects, verification output, and default dependence, but does not detail full spanning-tree operation.
Examples
Uses spanning-tree mode rapid-pvst with do show spanning-tree output showing protocol rstp.
What it assumes
Assumes basic Cisco IOS configuration and VLAN concepts while defining the relevant spanning-tree modes.
What you can do after
Operate/configure a Cisco switch and verify whether PVST+ or Rapid PVST+ is active.
How it connects
Connects spanning-tree mode with PVST+, Rapid PVST+, RSTP, VLANs, and show spanning-tree.
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