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Catalyst 2950 Desktop Switch Software Configuration Guide
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Chapter 11 Configuring STP
Configur ing Spanning-Tree F eatures
To return the switch to its default setting, use the no spanning-tree vlan vlan-id forward-time global
configurati on comm a nd.

Configuring the Maximum- Aging Time for a VLAN

Beginning in privileged EX EC mode, fol low these steps to con figure the maxi mum- aging tim e for a
VLAN:
To return the switch to its default setting, use the no spanning-tree vlan vlan-id max-ag e glob al
configurati on comm a nd.

Configuring STP for Use in a Cascaded Stack

STP uses default values tha t can be reduc ed when configuring your sw itch in ca scaded co nfiguration s.
If a root switch is part of a cluster that is one switch from a cascaded stack, you can customize spanning
tree to reconverge more quickly after a switch failure. Figure 11-4 shows switches in three cascaded
stacks tha t use the GigaStac k GBIC. Table 11-4 shows the default STP settings and those that are
acceptable for these configurations.
Command Purpose
Step 1 configure terminal Enter g lob al c onfigura tion m ode .
Step 2 spanning-tree vlan vlan -id max-age seconds Configure the maxi mum- aging tim e of a VLAN. The
maxim um-agi ng time is the num ber of se conds a switc h waits
without rec eiving spanni ng -tr ee co nfigurat ion m es sag es bef ore
attemp ting a re configur ation.
For vlan-id, the range is 1 to 4094 when the EI is installed
and 1 to 1005 when the SI is installed. Do not enter leading
zeros.
For seconds, the range is 6 to 40; the default is 20.
Step 3 end Return to pr ivileged EX EC m ode.
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.
Table 11-4 Default and Acceptable STP Parameter Settings (in seconds)
STP Parameter STP Default Acceptable for Option 1 Acceptable for Option 2 Acceptable for Option 3
Hello Time 2 1 1 1
Max Age 20 6 10 6
Forwarding D ela y 15 4 7 4