To set an interface priority when two bridges compete for position as the root bridge, use the spanning-tree port-priority command. The priority you set breaks the tie. To return to the default settings, use the no form of this command.
spanning-tree [vlan vlan-id] port-priority value
no spanning-tree [vlan vlan-id] port-priority
vlan vlan-id |
(Optional) Specifies the VLAN identification number. The range is from 0 to 4094. |
value |
Port priority. The range is from 1 to 224, in increments of 32. |
Port priority default value is 128.
Interface configuration mode
Release |
Modification |
4.0(0)N1(1a) |
This command was introduced. |
Do not use the vlan vlan-id parameter on access ports. The software uses the port priority value for access ports and the VLAN port priority values for trunk ports.
The priority values are 0, 32, 64, 96, 128, 160, 192, and 224. All other values are rejected.
Note Use this command to configure the port priority for Rapid per VLAN Spanning Tree Plus (Rapid PVST+) spanning tree mode, which is the default STP mode. To configure the port priority for Multiple Spanning Tree (MST) spanning tree mode, use the spacing-tree mst port-priority command.
This example shows how to increase the probability that the spanning tree instance on access port interface 2/0 is chosen as the root bridge by changing the port priority to 32:
switch(config-if)# spanning-tree port-priority 32
Command |
Description |
---|---|
show spanning-tree |
Displays information about the spanning tree state. |
spanning-tree interface priority |
Displays information on the spanning tree port priority for the interface. |