Cisco Systems 3750E manual Configuring Spanning-Tree Timers, Configuring the Hello Time, 18-22

Chapter 18 Configuring STP

Configuring Spanning-Tree Features

Configuring Spanning-Tree Timers

		Table 18-4describes the timers that affect the entire spanning-tree performance.
Table 18-4	Spanning-Tree Timers
Variable			Description
Hello timer			Controls how often the switch broadcasts hello messages to other switches.
Forward-delay timer			Controls how long each of the listening and learning states last before the interface begins
			forwarding.
Maximum-age timer			Controls the amount of time the switch stores protocol information received on an interface.
Transmit hold count			Controls the number of BPDUs that can be sent before pausing for 1 second.

The sections that follow provide the configuration steps.

Configuring the Hello Time

You can configure the interval between the generation of configuration messages by the root switch by changing the hello time.

Note Exercise care when using this command. For most situations, we recommend that you use the spanning-tree vlan vlan-idroot primary and the spanning-tree vlan vlan-idroot secondary global configuration commands to modify the hello time.

Beginning in privileged EXEC mode, follow these steps to configure the hello time of a VLAN. This procedure is optional.

	Command	Purpose
Step 1
	configure terminal	Enter global configuration mode.
Step 2
	spanning-tree vlan vlan-idhello-time seconds	Configure the hello time of a VLAN. The hello time is the
		interval between the generation of configuration messages by
		the root switch. These messages mean that the switch is alive.
		• For vlan-id, you can specify a single VLAN identified by
		VLAN ID number, a range of VLANs separated by a
		hyphen, or a series of VLANs separated by a comma. The
		range is 1 to 4094.
		• For seconds, the range is 1 to 10; the default is 2.
Step 3
	end	Return to privileged EXEC mode.
Step 4
	show spanning-tree vlan vlan-id	Verify your entries.
Step 5
	copy running-config startup-config	(Optional) Save your entries in the configuration file.

To return to the default setting, use the no spanning-tree vlan vlan-idhello-timeglobal configuration command.

	Catalyst 3750-E and 3560-E Switch Software Configuration Guide
18-22	OL-9775-02