Cisco--stp--生成树-根网桥

 SW0

Switch>en
Switch#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
Switch(config)#int r f0/1 - 4
Switch(config-if-range)#sw trunk encapsulation dot1q 
Switch(config-if-range)#sw m t

Sw1

Switch>en
Switch#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
Switch(config)#int r f0/1 - 4
Switch(config-if-range)#sw trunk encapsulation dot1q 
Switch(config-if-range)#sw m t

SW0

Switch(config-if-range)#exit
Switch(config)#vtp domain ddd
Changing VTP domain name from NULL to ddd
Switch(config)#vlan 2
Switch(config-vlan)#vlan 3

S1

Switch>en
Switch#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
Switch(config)#int f0/3
Switch(config-if)#sw a v 2
Switch(confi