基于端口的vlan配置

原创

netcisco 2009-06-28 02:59:36 ©著作权

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vlan也就是虚拟局域网，它们是在逻辑上划分出来的，实现的效果跟真实的局域网差不多，但是虚拟局域网有着很大的灵活性，是现在组网中比较常用的。vlan的实现是在数据链路层，我们知道普通的以太网数据帧格式是这样的：目的MAC地址（6字节）、源MAC地址（6字节）、类型/长度（2字节）、数据（46~1500字节）、帧校验序列（4字节）。虚拟局域网801.1q的数据帧和普通以太网数据帧不同就在于它在类型/长度字段前加了4字节的vlan标签字段。

实验拓扑结构：

实验描述：

pc0、pc2和pc3同属vlna 2，pc1属于vlna 3，pc0和pc1是不能够通信的，因为他们在不同的虚拟局域网中，pc0、pc2、pc3之间能够通信，pc0和pc2之间通信是通过trunk链路实现的，因为pc0和pc2是不同设备相同vlan之间的通信，假若不借用trunk链路，那么switch0的fa0/3和switch1的fa0/1都得划分给vlan 2然后连接他们之间的物理线路，这样做有个坏处，那就是浪费端口，试想假若switch0中的vlan 3要和switch1中的vlna 3通信，那么还的从SW1和SW2中分别再各拿出一个端口划分给vlan 3然后再连接物理线路。trunk的作用就是一条线路承载多个vlan的通信。pc2和pc3之间的通信是不经过trunk的，因为它们是在同一设备上进行的。

pc0

ip	192.168.1.1	vlan2
mask	255.255.255.0
gataway

pc1

ip	192.168.2.1	vlan3
mask	255.255.255.0
gataway

pc2

ip	192.168.1.2	vlan2
mask	255.255.255.0
gataway

pc3

ip	192.168.1.3	vlan2
mask	255.255.255.0
gataway

注：交换机默认所有的端口属于vlan 1中，所以我们从2以上划分。

实验操作：

switch0

Switch>enable

Switch#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)#hostname switch0
switch0(config)#exit
%SYS-5-CONFIG_I: Configured from console by console
switch0#vlan database
% Warning: It is recommended to configure VLAN from config mode,
as VLAN database mode is being deprecated. Please consult user
documentation for configuring VTP/VLAN in config mode.

switch0(vlan)#vlan 2 name 2
VLAN 2 modified:
Name: 2

switch0(vlan)#vlan 3 name 3
VLAN 3 modified:
Name: 3
switch0(vlan)#exit
APPLY completed.
Exiting....
switch0#conf t
Enter configuration commands, one per line. End with CNTL/Z.
switch0(config)#interface f
switch0(config)#interface fastEthernet0/1

switch0(config-if)#switchport mode access
switch0(config-if)#switchport access vlan 2
switch0(config-if)#exit
switch0(config)#interface fastEthernet0/2

switch0(config-if)#switchport mode access
switch0(config-if)#switchport access vlan 3

switch0(config-if)#exit
switch0(config)#interface fastEthernet0/3

switch0(config-if)#switchport mode trunk

switch0(config-if)#exit
switch0(config)#exit
%SYS-5-CONFIG_I: Configured from console by console
switch0#copy run star
Destination filename [startup-config]?
Building configuration...
[OK]

switch1

Switch>enable

Switch#conf t
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)#hostname switch1
switch1(config)#vlan database
^
% Invalid input detected at '^' marker.

switch1(config)#exit
%SYS-5-CONFIG_I: Configured from console by console
switch1#vlan database
% Warning: It is recommended to configure VLAN from config mode,
as VLAN database mode is being deprecated. Please consult user
documentation for configuring VTP/VLAN in config mode.

switch1(vlan)#vlan 2 name 2
VLAN 2 modified:
Name: 2
switch1(vlan)#vlna 3 name 3
^
% Invalid input detected at '^' marker.

switch1(vlan)#exit
APPLY completed.
Exiting....
switch1#conf t
Enter configuration commands, one per line. End with CNTL/Z.
switch1(config)#int
switch1(config)#interface f
switch1(config)#interface fastEthernet0/1
switch1(config-if)#switchport mode trunk
switch1(config-if)#exit
switch1(config)#interface fastEthernet0/2
switch1(config-if)#switchport mode access
switch1(config-if)#switchport access vlan 2
switch1(config-if)#exit
switch1(config)#interface fastEthernet0/3
switch1(config-if)#switchport mode access
switch1(config-if)#switchport access vlan 2
switch1(config-if)#end
%SYS-5-CONFIG_I: Configured from console by console
switch1#copy running-config st
switch1#copy running-config startup-config
Destination filename [startup-config]?
Building configuration...
[OK]

测试：

PC0>192.168.1.2
Invalid Command.

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=187ms TTL=128
Reply from 192.168.1.2: bytes=32 time=94ms TTL=128
Reply from 192.168.1.2: bytes=32 time=78ms TTL=128
Reply from 192.168.1.2: bytes=32 time=94ms 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 = 78ms, Maximum = 187ms, Average = 113ms，ping通

PC0>ping 192.168.2.1

Pinging 192.168.2.1 with 32 bytes of data:

Request timed out.
Request timed out.
Request timed out.
Request timed out.

Ping statistics for 192.168.2.1:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),ping不通

成功........

总结：

关于虚拟局域网的划分有多种方式基于端口的划分是其中一种，但是也是比较流行的一种，例外还有基于MAC地址和基于协议的划分等。