Vlan(Virtual Local Area Network)即虛拟區域網路。VLAN可以把同一個實體網絡劃分為多個邏輯網段，是以，Vlan可以抑制網絡風暴，增強網絡的安全性。
一、執行個體拓撲圖
PC1的配置：
PC>ipconfig 192.168.0.1 255.255.255.0
配置前的測試：
PC>ping 192.168.0.2
Pinging 192.168.0.2 with 32 bytes of data:
Reply from 192.168.0.2: bytes=32 time=125ms TTL=128
Reply from 192.168.0.2: bytes=32 time=62ms TTL=128
Reply from 192.168.0.2: bytes=32 time=63ms TTL=128
Ping statistics for 192.168.0.2:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 62ms, Maximum = 125ms, Average = 78ms
PC>ping 192.168.0.3
Pinging 192.168.0.3 with 32 bytes of data:
Reply from 192.168.0.3: bytes=32 time=109ms TTL=128
Reply from 192.168.0.3: bytes=32 time=47ms TTL=128
Reply from 192.168.0.3: bytes=32 time=63ms TTL=128
Ping statistics for 192.168.0.3:
Minimum = 47ms, Maximum = 109ms, Average = 70ms
二、建立VLAN在Cisco IOS中有兩種方式建立vlan,在全局配置模式下使用vlan vlanid指令，如switch(config)#vlan 10；在vlan database下建立vlan,如switch(vlan)vlan 20
Swtich
Switch>enable
Switch#config terminal
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)#vlan 10
Switch(config-vlan)#vlan 20
Switch(config-vlan)#end
Switch#show vlan
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Fa0/1, Fa0/2, Fa0/3, Fa0/4
Fa0/5, Fa0/6, Fa0/7, Fa0/8
Fa0/9, Fa0/10, Fa0/11, Fa0/12
Fa0/13, Fa0/14, Fa0/15, Fa0/16
Fa0/17, Fa0/18, Fa0/19, Fa0/20
Fa0/21, Fa0/22, Fa0/23, Fa0/24
10 VLAN0010 active
20 VLAN0020 active
三、把端口劃分給vlan(基于端口的vlan)Switch(config)#interface fa0/1
Switch(config-if)#switchport mode access
Switch(config-if)#switchport access vlan 10
Switch(config-if)#exit
Switch(config)#interface fa0/2
Switch(config-if)#switchport mode access
Switch(config)#interface fa0/3
Switch(config-if)#switchport access vlan 20
Switch(config)#interface fa0/4
四、檢視vlan資訊1 default active Fa0/5, Fa0/6, Fa0/7, Fa0/8
10 VLAN0010 active Fa0/1, Fa0/2
20 VLAN0020 active Fa0/3, Fa0/4
配置後的測試：
Minimum = 62ms, Maximum = 63ms, Average = 62ms
Request timed out.
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss)
計算機的配置：
PC>ipconfig 192.168.0.2 255.255.255.0
PC>ipconfig 192.168.0.3 255.255.255.0
PC>ipconfig 192.168.0.4 255.255.255.0
PC>ipconfig 192.168.0.5 255.255.255.0
交換機的配置：
Switch#configure terminal
Switch(config-vlan)#exit
Switch(config)#interface fa0/24
Switch(config-if)#switchport mode trunk
Switch(config)#
Switch(config-if)#
測試：
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),
PC>ping 192.168.0.4
Pinging 192.168.0.4 with 32 bytes of data:
Ping statistics for 192.168.0.4:
PC>ping 192.168.0.5
Pinging 192.168.0.5 with 32 bytes of data:
Reply from 192.168.0.5: bytes=32 time=94ms TTL=128
Reply from 192.168.0.5: bytes=32 time=78ms TTL=128
Ping statistics for 192.168.0.5: