DTP
拓撲：
實驗步驟：
(1)交換機VLAN 劃分，將端口加入相應VLAN
(2) DTP使用
sw0(config)#interface f0/3
sw0(config-if)#switchport mode dynamic desirable //期望對端是 trunk auto desirable時自動成爲中繼鏈路
sw1(config)#interface f0/3
sw1(config-if)#switchport mode dynamic auto
%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/3, changed state to up
sw1(config-if)#
調試
sw0(config)#do show inter tru
Port Mode Encapsulation Status Native vlan
Fa0/3 auto n-802.1q trunking 1
Port Vlans allowed on trunk
Fa0/3 1-1005
Port Vlans allowed and active in management domain
Fa0/3 1,2,3
Port Vlans in spanning tree forwarding state and not pruned
Fa0/3 none
sw0(config)#
#switchport mode access //永久非中繼鏈路
#switchport mode dynamic auto //自動 對端trunk desirable時自動成爲中繼鏈路
#switchport mode trunk //永久中繼鏈路
#switchport nonegotiate //永久中繼鏈路，但禁止接口產生DTP幀，建立中繼鏈路，就必須手工將領接接口配置爲中繼接口