某网络的拓扑结构如图4－1所示，其中路由器Router1和交换机Switch1的部分配置如下：以下是路由器Rou

某网络的拓扑结构如图4-1所示，其中路由器Router1和交换机Switch1的部分配置如下：

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