Chapter 18 Configuring STP

Configuring Spanning-Tree Features

Configuring the Forwarding-Delay Time for a VLAN

Beginning in privileged EXEC mode, follow these steps to configure the forwarding-delay time for a VLAN. This procedure is optional.

 

Command

Purpose

Step 1

 

 

configure terminal

Enter global configuration mode.

Step 2

 

 

spanning-tree vlan vlan-idforward-time

Configure the forward time of a VLAN. The forward delay is the

 

seconds

number of seconds an interface waits before changing from its

 

 

spanning-tree learning and listening states to the forwarding state.

 

 

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 4 to 30; the default is 15.

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-idforward-timeglobal configuration command.

Configuring the Maximum-Aging Time for a VLAN

Beginning in privileged EXEC mode, follow these steps to configure the maximum-aging time for a VLAN. This procedure is optional.

 

 

Command

Purpose

 

 

Step 1

 

 

 

 

configure terminal

Enter global configuration mode.

 

 

Step 2

 

 

 

 

spanning-tree vlan vlan-idmax-age seconds

Configure the maximum-aging time of a VLAN. The

 

 

 

 

maximum-aging time is the number of seconds a switch waits

 

 

 

 

without receiving spanning-tree configuration messages before

 

 

 

 

attempting a reconfiguration.

 

 

 

 

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 6 to 40; the default is 20.

 

 

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-idmax-ageglobal configuration

 

 

 

command.

 

 

 

 

 

 

 

Catalyst 3750-E and 3560-E Switch Software Configuration Guide

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

OL-9775-02

 

 

18-23

 

 

 

 

 

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Cisco Systems 3750E Configuring the Forwarding-Delay Time for a Vlan, Configuring the Maximum-Aging Time for a Vlan, 18-23