实验45:trunk 配置<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
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
转载于:https://blog.51cto.com/gauyanm/242915