DTP

DTP拓扑：

实验步骤：(1)交换机VLAN 划分，将端口加入相应VLAN (2) DTP使用 sw0(config)#interface f0/3sw0(config-if)#switchport mode dynamic desirable //期望对端是 trunk auto desirable时自动成为中继链路sw1(config)#interface f0/3sw1(config-if)#switchport mode dynamic auto %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/3, changed state to upsw1(config-if)#调试sw0(config)#do show inter truPort Mode Encapsulation Status Native vlanFa0/3 auto n-802.1q trunking 1Port Vlans allowed on trunkFa0/3 1-1005Port Vlans allowed and active in management domainFa0/3 1,2,3Port Vlans in spanning tree forwarding state and not prunedFa0/3 nonesw0(config)##switchport mode access //永久非中继链路#switchport mode dynamic auto //自动 对端trunk desirable时自动成为中继链路#switchport mode trunk //永久中继链路#switchport nonegotiate //永久中继链路，但禁止接口产生DTP帧，建立中继链路，就必须手工将领接接口配置为中继接口