单臂路由(router-on-a-stick)是指在路由器的一个接口上通过配置子接口(或“逻辑接口”,并不存在真正物理接口)的方式,实现原来相互隔离的不同VLAN(虚拟局域网)之间的互联互通。
操作:按照如图所示连接拓扑图
(1)创建拓扑,配置设备
添加一台路由器、一台交换机和四台主机
PC0和PC1与交换机fa0/1、fa0/2 接口连接,划分在VLAN10中,IP分别为192.168.10.1、192.168.10.2,网关192.168.10.254。
PC2和PC3与交换机fa0/11、fa0/12 接口连接,划分在VLAN20中,IP分别为192.168.20.1、192.168.20.2,网关192.168.20.254。
交换机fa0/24端口与路由器fa0/1端口连接。
(2)配置交换机
- /* Part 1 配置交换机 */
- Switch>enable
- Switch#configure terminal
- Switch(config)#hostname SA
- SA(config)#vlan 10
- SA(config-vlan)#vlan 20
- SA(config-vlan)#exit
- SA(config)#interface range fa0/1-fa0/2
- SA(config-if-range)#switchport access vlan 10
- SA(config-if-range)#interface range fa0/11-fa0/12
- SA(config-if-range)#switchport access vlan 20
- SA(config-if-range)#interface fa0/24
- SA(config-if)#switchport mode trunk
- SA(config-if)#switchport trunk allowed vlan all
-
- /* Part 2 检查配置 */
- SA(config-if-range)#^Z (Ctrl+Z组合键)
- SA#show vlan
- ...
- VLAN Name Status Ports
- ---- -------------------------------- --------- -------------------------------
- 1 default active Fa0/3, Fa0/4, Fa0/5, Fa0/6
- Fa0/7, Fa0/8, Fa0/9, Fa0/10
- Fa0/13, Fa0/14, Fa0/15, Fa0/16
- Fa0/17, Fa0/18, Fa0/19, Fa0/20
- Fa0/21, Fa0/22, Fa0/23
- 10 VLAN0010 active Fa0/1, Fa0/2
- 20 VLAN0020 active Fa0/11, Fa0/12
- ...
(3)配置路由器
- /* Part 1 配置路由器 */
- Router>enable
- Router#configure terminal
- Router(config)#hostname RA
- RA(config)#interface fa0/0.1
- RA(config-subif)#encapsulation dot1Q 10
- // (1:在路由器上配置trunk的封装协议的命令:
- // encapsulation [isl/dot1q] vlan#
- // 2:上面的路由器配置了dot1q中继封装,10是vlan 10。
- // 3:Trunk的封装类型一共有 ISL和802.1Q两种,而802.1Q在输入的时候为dot1q)
- RA(config-subif)#ip address 192.168.10.254 255.255.255.0
- RA(config-subif)#interface fa0/0.2
- RA(config-subif)#encapsulation dot1Q 20
- RA(config-subif)#ip address 192.168.20.254 255.255.255.0
- RA(config-subif)#exit
- RA(config)#interface fa0/0
- RA(config-if)#shutdown
- RA(config-if)#no shutdown //(重启fa0/0接口)
-
- /* Part 2 检查配置 */
- RA>show interfaces fa0/0.1
- ...
- Internet address is 192.168.1.254/24
- ...
- Encapsulation 802.1Q Virtual LAN, Vlan ID 10
- ...
-
- RA>show interfaces fa0/0.2
- ...
- Internet address is 192.168.2.254/24
- ...
- Encapsulation 802.1Q Virtual LAN, Vlan ID 20
- ...
(4)连通性测试
- /* Part 1 PC0 Ping 自己网关 */
- PC>ping 192.168.1.254
-
- Pinging 192.168.1.254 with 32 bytes of data:
-
- Reply from 192.168.1.254: bytes=32 time=11ms TTL=255
- Reply from 192.168.1.254: bytes=32 time=12ms TTL=255
- Reply from 192.168.1.254: bytes=32 time=11ms TTL=255
- Reply from 192.168.1.254: bytes=32 time=12ms TTL=255
-
- Ping statistics for 192.168.1.254:
- Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
- Approximate round trip times in milli-seconds:
- Minimum = 11ms, Maximum = 12ms, Average = 11ms
-
- /* Part 2 PC0 Ping PC1 */
- PC>ping 192.168.1.2
-
- Pinging 192.168.1.2 with 32 bytes of data:
-
- Reply from 192.168.1.2: bytes=32 time=25ms TTL=128
- Reply from 192.168.1.2: bytes=32 time=10ms TTL=128
- Reply from 192.168.1.2: bytes=32 time=12ms TTL=128
- Reply from 192.168.1.2: bytes=32 time=14ms TTL=128
-
- Ping statistics for 192.168.1.2:
- Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
- Approximate round trip times in milli-seconds:
- Minimum = 10ms, Maximum = 25ms, Average = 15ms
-
-
- /* Part 3 PC0 Ping PC2 PC3网关 */
- PC>ping 192.168.2.254
-
- Pinging 192.168.2.254 with 32 bytes of data:
-
- Reply from 192.168.2.254: bytes=32 time=11ms TTL=255
- Reply from 192.168.2.254: bytes=32 time=14ms TTL=255
- Reply from 192.168.2.254: bytes=32 time=11ms TTL=255
- Reply from 192.168.2.254: bytes=32 time=12ms TTL=255
-
- Ping statistics for 192.168.2.254:
- Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
- Approximate round trip times in milli-seconds:
- Minimum = 11ms, Maximum = 14ms, Average = 12ms
-
-
- /* Part 4 PC0 Ping PC2 */
- PC>ping 192.168.2.1
-
- Pinging 192.168.2.1 with 32 bytes of data:
-
- Reply from 192.168.2.1: bytes=32 time=24ms TTL=127
- Reply from 192.168.2.1: bytes=32 time=19ms TTL=127
- Reply from 192.168.2.1: bytes=32 time=21ms TTL=127
- Reply from 192.168.2.1: bytes=32 time=20ms TTL=127
-
- Ping statistics for 192.168.2.1:
- Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
- Approximate round trip times in milli-seconds:
- Minimum = 19ms, Maximum = 24ms, Average = 21ms
-
-
- /* Part 5 PC0 Ping PC3 */
- PC>ping 192.168.2.2
-
- Pinging 192.168.2.2 with 32 bytes of data:
-
- Request timed out.
- Reply from 192.168.2.2: bytes=32 time=24ms TTL=127
- Reply from 192.168.2.2: bytes=32 time=22ms TTL=127
- Reply from 192.168.2.2: bytes=32 time=19ms TTL=127
-
- Ping statistics for 192.168.2.2:
- Packets: Sent = 4, Received = 3, Lost = 1 (25% loss),
- Approximate round trip times in milli-seconds:
- Minimum = 19ms, Maximum = 24ms, Average = 21ms
由实验可知,划分VLAN后不同VLAN间的主机不能通信,可以使用路由器进行VLAN间通信。
注意:
1、主机需要配网关。
2、当出现Ping不通别的主机时,可以采用由近及远的检查方式,即依次Ping自己、自己的网关、对方主机的网关、对方主机以便于发现错误位置。