Cisco 2950G 24 Software Configuration Guide - Page 334

Configuring Optional Spanning-Tree Features Chapter 13 Configuring Optional Spanning-Tree Features Step 5 Step 6 Command Purpose show running-config Verify your entries. copy running-config startup-config (Optional) Save your entries in the configuration file. To disable root guard, use the no spanning-tree guard interface configuration command. Enabling Loop Guard You can use loop guard to prevent alternate or root ports from becoming designated ports because of a failure that leads to a unidirectional link. This feature is most effective when it is configured on the entire switched network. Loop guard operates only on ports that are considered point-to-point by the spanning tree. Note You cannot enable both loop guard and root guard at the same time. You can enable this feature if your switch is running PVST or MSTP. The MSTP is available only if you have the EI installed on your switch. Beginning in privileged EXEC mode, follow these steps to enable loop guard: Step 1 Step 2 Step 3 Command show spanning-tree active or show spanning-tree mst configure terminal spanning-tree loopguard default Step 4 Step 5 Step 6 end show running-config copy running-config startup-config Purpose Determine which ports are alternate or root ports. Enter global configuration mode. Enable loop guard. By default, loop guard is disabled. Return to privileged EXEC mode. Verify your entries. (Optional) Save your entries in the configuration file. To globally disable loop guard, use the no spanning-tree loopguard default global configuration command. You can override the setting of the no spanning-tree loopguard default global configuration command by using the spanning-tree guard loop interface configuration command. 13-20 Catalyst 2950 Desktop Switch Software Configuration Guide 78-14982-01