Configuring global spanning tree


spanning-tree extend system-id

Creates a unique bridge identifier for each VLAN by adding the VLAN ID (vid) value to the priority field of the bridge identifier in every RPVST+ BPDU.


no spanning-tree log state-transitions [instance <instance-id> cst]
  • The command enables or disables event logging for port-block events.

  • List of VLAN identifiers

  • Range: <instance-id> 1–16

    [vlan <vid-list>]


no spanning-tree ignore-pvid-inconsistency

Causes the switch to ignore per-VLAN ID inconsistencies when the ports on both ends of a point-to-point link are untagged members of different VLANs, thus allowing RPVST+ to run on the mismatched links. On a given switch, affects all ports belonging to VLANs on which RPVST+ is enabled.

Default: Disabled


The no form of this command is ineffective when there is a PVID inconsistency between a VLAN1 and any non-VLAN1 member because VLAN1 uses IEEE BPDUs to form a spanning tree topology.


no spanning-tree bpdu-protection-timeout timeout
  • Configures the duration of time when protected ports receiving unauthorized BPDUs will remain disabled. The default value of 0 (zero) sets an infinite timeout (that is, ports that are disabled by bpdu-protection are not, by default, re-enabled automatically).
  • Default: 0
  • Range: 0 - 65535 seconds