Switch(config)#int f0/1
Switch(config-if)#switchport trunk encap dot1q
Switch(config-if)#switchport mode trunk
Switch(config-if)#exit
Switch(config)#int f0/2
Switch(config-if)#switchport trunk encap dot1q
Switch(config-if)#switchport mode trunk
Switch(config-if)#exit
Switch(config)#

Switch(config)#spanning-tree vlan 1 priority 0 
Switch(config)#spanning-tree vlan 10 priority 0 
Switch(config)#spanning-tree vlan 20 priority 0 
Switch(config)#spanning-tree vlan 30 priority 0 
Switch(config)#exit
Switch#