Cisco Catalyst 3550

2-543
Catalyst 3550 Multilayer Switch Command Reference
OL-8566-01
Chapter 2 Catalyst 3550 Switch Cisco IOS Commands
spanning-tree mst max-age
spanning-tree mst max-age
Use the spanning-tree mst max-age global configuration command to set the interval between
messages that 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 topology. Use the no form of this command to return to the default setting.
spanning-tree mst max-age seconds
no spanning-tree mst max-age
Syntax Description
Defaults The default is 20 seconds.
Command Modes Global configuration
Command History
Usage Guidelines After you set the spanning-tree mst max-age seconds global configuration command, if a switch does
not receive BPDUs from the root switch within the specified interval, the switch recomputes the
spanning-tree topology. The max-age setting must be greater than the hello-time setting.
Changing the spanning-tree mst max-age command affects all spanning-tree instances.
Examples This example shows how to set the spanning-tree max-age to 30 seconds for all MST instances:
Switch(config)# spanning-tree mst max-age 30
You can verify your settings by entering the show spanning-tree mst privileged EXEC command.
Related Commands
seconds Interval between messages the spanning tree receives from the root switch. If a switch
does not receive a BPDU message from the root switch within this interval, it
recomputes the spanning-tree topology. The range is 6 to 40 seconds.
Release Modification
12.1(9)EA1 This command was introduced.
Command Description
show spanning-tree mst Displays multiple spanning-tree (MST) information.
spanning-tree mst forward-time Sets the forward-delay time for all MST instances.
spanning-tree mst hello-time Sets the interval between hello BPDUs sent by root switch
configuration messages.
spanning-tree mst max-hops Sets the number of hops in a region before the BPDU is
discarded.