HP Cisco Catalyst Blade Switch 3020 Cisco Catalyst Blade Switch 3020 for HP Co - Page 477
spanning-tree loopguard default
View all HP Cisco Catalyst Blade Switch 3020 manuals
Add to My Manuals
Save this manual to your list of manuals |
Page 477 highlights
Chapter 2 Cisco Catalyst Blade Switch 3020 for HP Cisco IOS Commands spanning-tree loopguard default spanning-tree loopguard default Use the spanning-tree loopguard default global configuration command to prevent alternate or root ports from becoming designated ports because of a failure that leads to a unidirectional link. Use the no form of this command to return to the default setting. spanning-tree loopguard default no spanning-tree loopguard default Syntax Description This command has no arguments or keywords. Defaults Loop guard is disabled. Command Modes Global configuration Command History Release 12.2(25)SEF Modification This command was introduced. Usage Guidelines You can enable the loop guard feature when the switch is operating in the per-VLAN spanning-tree plus (PVST+), rapid-PVST+, or the multiple spanning-tree (MST) mode. Loop guard is most effective when it is configured on the entire switched network. When the switch is operating in PVST+ or rapid-PVST+ mode, loop guard prevents alternate and root ports from becoming designated ports, and spanning tree does not send bridge protocol data units (BPDUs) on root or alternate ports. When the switch is operating in MST mode, BPDUs are not sent on nonboundary interfaces if the interface is blocked by loop guard in all MST instances. On a boundary interface, loop guard blocks the interface in all MST instances. Loop guard operates only on interfaces that the spanning tree identifies as point-to-point. You can override the setting of the spanning-tree loopguard default global configuration command by using the spanning-tree guard loop interface configuration command. Examples This example shows how to globally enable loop guard: Switch(config)# spanning-tree loopguard default You can verify your settings by entering the show running-config privileged EXEC command. OL-8916-01 Cisco Catalyst Blade Switch for HP Command Reference 2-449