Users Guide
disable
• Disable PVST+ on an interface, or remove a PVST+ parameter configuration.
INTERFACE mode
no spanning-tree pvst
Example of Viewing PVST+ Configuration
To display your PVST+ configuration, use the show config command from PROTOCOL PVST mode.
Dell_E600(conf-pvst)#show config verbose
!
protocol spanning-tree pvst
no disable
vlan 100 bridge-priority 4096
Influencing PVST+ Root Selection
As shown in the previous PVST+ illustration, all VLANs use the same forwarding topology because R2 is elected the root, and all
TengigabitEthernet ports have the same cost.
The following per-VLAN spanning tree illustration changes the bridge priority of each bridge so that a different forwarding
topology is generated for each VLAN. This behavior demonstrates how you can use PVST+ to achieve load balancing.
Figure 102. Load Balancing with PVST+
The bridge with the bridge value for bridge priority is elected root. Because all bridges use the default priority (until configured
otherwise), the lowest MAC address is used as a tie-breaker. To increase the likelihood that a bridge is selected as the STP root,
assign bridges a low non-default value for bridge priority.
To assign a bridge priority, use the following command.
Per-VLAN Spanning Tree Plus (PVST+) 657