Trunk配置實例

 Trunk配置實例

　如圖，兩臺交換機SW１和SW2各劃分了三個VLAN，端口配置如下：

  VLAN 1: F0/1 - F0/3: VLAN 2: F0/4 - F0/10 VLAN 3: F0/11 - F0/23

  

兩臺交換機的配置類似，現在以SW1爲例，介紹Trunk配置與驗證的過程

1.在交換機上添加vlan
 

 

sw1(config)#vlan 2

sw1(config-vlan)#exit

 

sw1(config)#vlan 3

sw1(config-vlan)#exit

 

 

2.將接口添加到相應的VLAN中，命令如下

sw1(config)#interface range f0/4 - 10

sw1(config-if)#switchport mode access

sw1(config-if)#switchport access vlan 2

 

 

sw1(config)interface range f0/11 - 23

sw1(config-if)#switchport mode access

sw1(config-if)#switchport access vlan 3

 

 

3.配置交換機之間互聯的端口爲Trunk模式，命令如下

sw1(config)#interface f0/24

sw1(config-if)switchport mode trunk

4.在另一臺交換機上執行類似的配置，配置完成後，使用show命令進行驗證，命令如下。

 

SW1#show int fa0/24 switchport 

Name: Fa0/24

Switchport: Enabled

Administrative Mode: trunk

Operational Mode: trunk

Administrative Trunking Encapsulation: dot1q

Operational Trunking Encapsulation: dot1q

Negotiation of Trunking: On

Access Mode VLAN: 1 (default)

Trunking Native Mode VLAN: 1 (default)

Voice VLAN: none

Administrative private-vlan host-association: none

Administrative private-vlan mapping: none

Administrative private-vlan trunk native VLAN: none

Administrative private-vlan trunk encapsulation: dot1q

Administrative private-vlan trunk normal VLANs: none

Administrative private-vlan trunk private VLANs: none

Operational private-vlan: none

Trunking VLANs Enabled: ALL

Pruning VLANs Enabled: 2-1001

Capture Mode Disabled

Capture VLANs Allowed: ALL

   在上面的命令輸出中可以看出，在端口F0/24上配置接口模式爲Trunk，並且工作模式也是Trunk，

   Trunk封裝的協議是802.1Q，Trunk可以承載所有的VLAN。

 

5.如果不需要在Trunk上傳輸VLAN 2的數據，可以在Trunk上移除VLAN 2，如下所示

SW1(config)#interface fastEthernet 0/24

SW1(config-if)#switchport trunk allowed vlan remove 2

SW1(config-if)#exit

 

 

SW1#show int fa0/24 switchport 

Name: Fa0/24

Switchport: Enabled

Administrative Mode: trunk

Operational Mode: trunk

Administrative Trunking Encapsulation: dot1q

Operational Trunking Encapsulation: dot1q

Negotiation of Trunking: On

Access Mode VLAN: 1 (default)

Trunking Native Mode VLAN: 1 (default)

Voice VLAN: none

Administrative private-vlan host-association: none

Administrative private-vlan mapping: none

Administrative private-vlan trunk native VLAN: none

Administrative private-vlan trunk encapsulation: dot1q

Administrative private-vlan trunk normal VLANs: none

Administrative private-vlan trunk private VLANs: none

Operational private-vlan: none

Trunking VLANs Enabled: 1,3-1005

Pruning VLANs Enabled: 2-1001

Capture Mode Disabled

Capture VLANs Allowed: ALL

從上面show int fa0/24 switchport 命令的輸出可以看出，Trunk中已經移除了VLAN2。

Trunk的排錯

  VLAN中常見故障是設備不能跨越Trunk鏈路而建立連接。爲了能夠對Trunk接口的故障進行排錯，需要驗證下列配置是否正確。

1.接口模式

  要確保至少一則的鏈路的Trunk模式應當是Trunk或desirable。通過使用命令 show interfaces trunk 可以驗證接口的Trunk配置。

2。封裝類型

確保鏈路兩端的Trunk的封裝類型兼容