Command Spanning-Tree Backbonefast Use This command will prevent a switch that has lost its link to the root switch from becoming root when the root is still running. If switches receive an inferior BPDU from a switch, backbonefast will send them the proper information for reaching the root. …

Command VTP Mode Transparent Use VTP transparent mode allows the switch to modify its VLAN databasem but will not propagate changes from a server. Additionally, VTP transparent mode allows the switch to configure extended range VLANS (1006-4094). Syntax Switch(config)#vtp mode transparent Example In the below example we will …

Command Interface Range Use This is the modern way to configure VLANs. A useful feature is that you can configure a range of VLANs with a single command. Syntax Switch(config)#interface range <range> Options < – > Allows for a continuous range to be specified such as interface range …

Command Spanning-Tree VLAN Root Secondary Use This command sets the switch to become backup root for a given VLAN. It works by lowering the priority of the switch until it becomes one priority higher then the root, so it will take over if the root fails. Once the …

Command Spanning-Tree Portfast Use This command essentially disables spanning-tree on an interface and brings it immediately into the forwarding state. Only use this command on access ports Syntax Switch(config-if)#spanning-tree portfast Example In the below example we will configure SW1’s Fa0/2 to use port-fast to immediately skip to the …

Command VTP Password Use This command secures VTP updates by setting a secure password. Syntax Switch(config)#vtp password <password> Example In the below example we will set a password of ‘cisco’ for the VTP domain. CopySW1(config)#vtp password cisco Setting device VLAN database password to cisco SW2(config)#vtp password cisco Setting …

Command VTP Mode Client Use VTP client mode doesn’t allow you to create any VLANs. all VLANs must be learned from a server switch. This prevents the switch from accidently propogating VLANs throughout the network. Another use is to prevent an older switch from wiping out a server’s …

Command Vlan Use This is the modern way to configure VLANs. A useful feature of this command is that you can configure a range of VLANs with a single command. Syntax Switch(config)#vlan <vlan range> Options <name> Set VLAN name <exit> Apply changes and leave VLAN configuration mode Example …

Command Spanning-Tree Uplinkfast Use This command allows the switch to quickly select another root port if it detects a failure. The new root port moves from blocking to forwarding in under 5 seconds. Syntax Switch(config)#spanning-tree uplinkfast Example In the below example we will configure SW2 to use uplinkfast. …

Command Spanning-Tree VLAN Root Primary Use This command sets the switch to become root for a given VLAN. It works by lowering the priority of the switch until it becomes root. Once the switch is root, it will not prevent any other switch from becoming root. Syntax Swith(cconfig)#spanning-tree …