Command:

spanning-tree max-age

Mode:

Switch(config)#


Syntax:

spanning-tree [vlan stp-list] max-age seconds

no spanning-tree [vlan stp-list] max-age


Syntax Description:

vlan stp-list

(Optional) List of spanning-tree instances. Each spanning-tree instance is associated with a VLAN ID. Valid IDs are from 1 to 1001. Enter each VLAN ID separated by a space. Do not enter leading zeroes. Ranges are not supported.

seconds

Interval the switch waits between receiving BPDUs from the root switch.
Enter a number from 6 to 200.


Command Description:

Use the spanning-tree max-age global configuration command to change the interval between messages the spanning tree receives from the root switch. If a switch does not receive a Bridge Protocol Data Unit (BPDU) message from the root switch within this interval, it recomputes the Spanning Tree Protocol (STP) topology. Use the no form of this command to return to the default interval.

The max-age setting must be greater than the hello-time setting.

If the variable stp-list is omitted, the command applies to the STP instance associated with VLAN 1.

You can set the max-age on a VLAN that has no ports assigned to it. The setting takes effect when you assign ports to the VLAN.


Examples:

The following example shows how to set spanning-tree max-age to 30 seconds for VLAN 20:

Switch(config)#spanning-tree vlan 20 max-age 30

 

The following example shows how to reset the max-age parameter to the default value for spanning-tree instances 100 through 102:

Switch(config)#no spanning-tree vlan 100 101 102 max-age

 

You can verify the previous commands by entering the show spanning-tree command in privileged EXEC mode.


Misconceptions:
None

Related commands:
show spanning-tree
spanning-tree forward-time
spanning-tree hello-time
spanning-tree port-priority

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