实验45:trunk 配置
1. 实验目的
通过本实验，读者可以掌握如下技能：
（1） 配置交换机接口的trunk
（2） 理解DTP 的协商规律
2. 实验拓扑
拓扑图
3. 实验步骤
注：
1在Trunk 链路上，数据帧会根据ISL 或者802.1Q 被重新封装，然
而如果是Native VLAN 的数据，是不会被重新封装就在Trunk 链路上传输。很显然链路两端
的Native VLAN 是要一样的。如果不一样，交换机会提示出错
2和DTP 配置有关的有以下命令，这些命令不能任意组合：
“switchport trunk encapsulation ｛ negotiate | isl | dot1q ｝”：配置Trunk 链路
上的封装类型，可以是双方协商确定，也可以是指定的isl 或者dot1q
“switchport nonegotiate” ：Trunk 链路上不发送协商包，默认是发送的
“switch mode { trunk | dynamic desirable | dynamic auto }”：
???? trunk:这个设置将端口置为永久trunk 模式，封装类型由“switchport trunk
encapsulation”命令决定
???? dynamic desirable：端口主动变为trunk，如果另一端为negotiate、dynamic
desirable 、dynamic auto 将成功协商
???? dynamic auto：被动协商，如果另一端为negotiate、dynamic desirable 将成功
协商。
sw1(config)#int f0/2
sw1(config-if)#switchport trunk enca dot1q
//以上是配置trunk 链路的封装类型，同一链路的两端封装要相同。有的交换机，例如2950
只能封装dot1q，因此无需执行该命令。
sw1(config-if)#switch mode trunk//以上是把接口配置为trunk
sw1(config-if)#
*Mar 1 00:01:37.055: %DTP-5-TRUNKPORTON: Port Fa0/2 has become dot1q trunk
sw1(config-if)#^Z
sw1#v
*Mar 1 00:10:24.423: %SYS-5-CONFIG_I: Configured from console by console
sw1#vlan data
sw1(vlan)#vlan 2 name ke
VLAN 2 added:
Name: ke
sw1(vlan)#exit
APPLY completed.
Exiting....
sw1#vlan data
sw1(vlan)#vlan 3 name haojian
VLAN 3 added:
Name: haojian
sw1(vlan)#exit
APPLY completed.
Exiting....
sw1#conf t
Enter configuration commands, one per line. End with CNTL/Z.
sw1(config)#int f0/2
sw1(config-if)#do sh int f0/2 trunk
Port Mode Encapsulation Status Native vlan
Fa0/2 on 802.1q trunking 1
Port Vlans allowed on trunk
Fa0/2 1-1005
Port Vlans allowed and active in management domain
Fa0/2 1-3
Port Vlans in spanning tree forwarding state and not pruned
Fa0/2 1-3
检查trunk 链路的状态，测试跨交换机、同一VLAN 主机间的通信
使用“show interface f0/13 trunk”可以查看交换机端口的trunk 状态
f0/2 接口已经为trunk 链路了，封装为802.1q
sw1(config-if)#switchport trunk native vlan 2
sw1(config-if)#do sh int f0/2 trunk
Port Mode Encapsulation Status Native vlan
Fa0/2 on 802.1q trunking 2
Port Vlans allowed on trunk
Fa0/2 1-1005
Port Vlans allowed and active in management domain
Fa0/2 1-3
Port Vlans in spanning tree forwarding state and not pruned
Fa0/2 1-3
sw1(config-if)#exit
sw1(config)#exit
sw1#
*Mar 1 00:17:39.743: %SYS-5-CONFIG_I: Configured from console by console
sw1#vlan data
sw1(vlan)#vlan 2 name ke
VLAN 2 modified:
Name: ke
sw1(vlan)#exit
APPLY completed.
Exiting....
sw1#vlan da
sw1(vlan)#vlan 3 name haojian
VLAN 3 modified:
Name: haojian
sw1(vlan)#exit
APPLY completed.
Exiting....
sw1#conf t
Enter configuration commands, one per line. End with CNTL/Z.
sw1(config)#int f0/0
sw1(config-if)#swit mo acc
sw1(config-if)#swi acc vlan 2
sw1(config-if)#exit
sw1(config)#int f0/1
sw1(config-if)#swi m acc
sw1(config-if)#swi acc vlan 3
sw1(config-if)#exit
sw1(config)#
sw2(config)#int f0/2
sw2(config-if)#switchport trunk enca dot1q
sw2(config-if)#switch mode trunk
sw2(config-if)#
*Mar 1 00:02:30.071: %DTP-5-TRUNKPORTON: Port Fa0/2 has become dot1q trunk
sw2(config-if)#^Z
sw2#v
*Mar 1 00:09:37.703: %SYS-5-CONFIG_I: Configured from console by console
sw2#vlan data
sw2(vlan)#vlan 2 name ke
VLAN 2 added:
Name: ke
sw2(vlan)#exit
APPLY completed.
Exiting....
sw2#vlan dat
sw2(vlan)#vlan 3 name haojian
VLAN 3 added:
Name: haojian
sw2(vlan)#exit
APPLY completed.
Exiting....
sw2#
*Mar 1 00:12:26.787: %SPANTREE-2-RECV_PVID_ERR: Received BPDU with inconsistent peer vlan id 2 on FastEthernet0/2 VLAN1.
*Mar 1 00:12:26.787: %SPANTREE-2-BLOCK_PVID_PEER: Blocking FastEthernet0/2 on VLAN2. Inconsistent peer vlan.PVST+: restarted the forward delay timer for FastEthernet0/2
sw2#
*Mar 1 00:12:26.831: %SPANTREE-2-BLOCK_PVID_LOCAL: Blocking FastEthernet0/2 on VLAN1. Inconsistent local vlan.
sw2#conf t
Enter configuration commands, one per line. End with CNTL/Z.
sw2(config)#int f0/2
sw2(config-if)#switchport trunk native vlan 2
sw2(config-if)#PVST+: restarted the forward delay timer for FastEthernet0/2
*Mar 1 00:13:14.783: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking FastEthernet0/2 on VLAN1. Port consistency restored.
sw2(config-if)# PVST+:Inconsistency timer expired. inconsistency 0
cleared for FastEthernet0/2
sw2(config-if)#
*Mar 1 00:13:29.783: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking FastEthernet0/2 on VLAN2. Port consistency restored.
sw2(config-if)# PVST+:Inconsistency timer expired. inconsistency 0
cleared for FastEthernet0/2
sw2(config-if)#do ping 192.168.64.2
% Unrecognized host or address, or protocol not running.
sw2(config-if)#exit
sw2(config)#int f0/0
sw2(config-if)#switch mode access
sw2(config-if)#switch access vlan 2
sw2(config-if)#exit
sw2(config)#int f0/1
sw2(config-if)#switch mode access
sw2(config-if)#switch access vlan 2
本文转自gauyanm 51CTO博客，原文链接：http://blog.51cto.com/gauyanm/242915，如需转载请自行联系原作者
