以下是路由器Router和Switch1的部分配置信息，请解释部分命令的意义。
Router(config)#interface fastEthernet1/0.1
Router(config-subif)#encapsulation isl 11 (1)
Router(config-subif)#ip address 10.1.1.1 255.255.255.0 (2)
Router(config-subif)#exit
Router(config)#interface fastEthernet1/0.2
Router(config-subif)#encapsulation isl 12
Router(config-subif)#ip address 10.1.2.1 255.255.255.0
Router(config-subif)#exit
Router(config)#interface fastEthernet1/0.3
Router(config-subi f)#encapsulation isl 13
Router(config-subif)#ip address 10.1.3.1 255.255.255.0
Router(config-subif)#exit
Router(config)#ip routing (3)
[交换机Switch1的部分配置信息]
Switch1(config)#vlan database (4)
Switch1(vlan)#vlan 11 (5)
Switch1(vlan)#vlan 12
Switch1(vlan)#vlan 13
Switch1(vlan)#exit
Switch1(config)#interface fastEthernet0/0
Switch1(config-if)#switchport mode trunk (6)
Switch1(config-if)#switchport trunk allowed all (7)
Switch1(config-if)#exit
Switch1(config)#interface fastEthernet0/1
Switch1(config-if)#switchport mode trunk
Switch1(config-if)#switchport trunk a110wed a11
Switch1(config-if)#exit
Switch1(config)#interface fastEthernet0/2
Switch1(config-if)#switchport mode trunk
Switch1(config-if)#switchport trunk allowed all
Switch1(config-if)#exit
