Specifications

2-830
Catalyst 4500 Series Switch Cisco IOS Command Reference—Release IOS XE 3.3.0XO(15.1(1)XO)
OL_28738 -01
Chapter 2 Cisco IOS Commands for the Catalyst 4500 Series Switches
spanning-tree vlan
spanning-tree v lan
To configure STP o n a per-V LAN basis, use the spanning-tree vlan command. To return to the default
value, use the no form of this command.
spanning-tree vlan vlan_id [forward-time seconds | hello-time seconds | max-age seconds |
priority priority | protocol protocol | root {primary | secondary} [diameter net-diameter
[hello-time seconds]]]
no spanning-tree vlan vlan_id [ forward-time | hello-time | max-age | priority | root]
Syntax Description
Defaults T he default settings are as follows:
• Forward-time—15 seconds
• Hello-time—2 seconds
• Max- age—20 seconds
• Pri ority—32768 with STP ena bled; 128 with MST enabled
• Roo t—No STP root
Command Modes Global c onfiguratio n mode
Usage Guidelines W hen you are setting the m ax-age seconds value, if a br idge does not hear BPDUs from the root bri dge
within the specified interval, it assumes that the network has changed and recomputes the spanning-tree
topology.
The spanning-tree root primary command alters the switch bridge priority to 8192. If you enter the
spanning-tree root primary command and the sw itch does not become root, then th e bridge priority is
changed to 100 les s than the bridge p riority o f the current bridg e. If the switch does not become r oot, an
error will result.
vlan_id VLAN identification number; valid values are from 1 to 4094.
forward-time seconds (Optional) Sets the STP forward delay time; valid values are from 4 to
30 seconds.
hello-time seconds (Optional) Specifies, in seconds, the time between configuration messages
generated by the root switch; valid va lues are from 1 to 10 second s.
max-age seconds (Optional) Sets the maximum time, in seconds, that the information in a
BPDU is valid; valid values are from 6 to 40 seconds.
priority priority (Optional) Sets t he STP bridge priority; valid values are from 0 to 65535.
protocol protocol (Optional) Specifies the protocol.
root primary (Optional) Forces this switch to be the root bridge.
root secondary (Optional) Specifies this switch act as the root switch should the primary
root fail.
diameter net-diameter (Optional) Specifies the maximum number of bridges between two end
stations; valid values are from 2 to 7.