选择题 20.如下图所示，两台Catelyst 3548交换机通过千兆以太网端口连接，Catelyst 3548 A使用IEEE 802．1 Q协议，两台交换机之间需要传输ID号为10、14、24，VLAN名为libl0、libl4和lib24的3个VLAN，禁止传送ID号为100—1000的VLAN信息，下列交换机B的VLAN配置，正确的是( )。

A、 Switch一3548#vlan data Switch一3548(vlan)#vlan 10 liblO Switch一3548(vlan)#vlan 14 libl4 Switch一3548(vlan)#vlan 24 lib24 Switch一3548(vlan)#exit Switch—-3548#configure terminal Switch一3548(config)#interface gO／8 Switch一3548(config—if)#switchpoa mode trunk Switch一3548(config—if)#switchpoa trunk encapsulation isl Switch一3548(config—if)#switchpo~trunk allowed vlan 10，14，24 Switch一3548(config—if)#switchpoa trunk allowed vlan except 100—1000 Switch一3548(config—if)#exit
B、 Switch一3548#vlan data Switch一3548(vlan)#vlan 10 name libl0 Switch一3548(vlan)#vlan 14 name libl4 Switch一3548(vlan)#vlan 24 name lib24 Switch一3548(vlan)#exit Switch—-3548#configure terminal Switch一3548(config)#interface g0／8 Switch一3548(config—if)#switchport mode trunk Switch一3548(config—if)#switchpo~trunk encapsulation dotl q Switch一3548(config—if)#switchport trunk allowed vlan 10，14，24 Switch一3548(config—if)#switchpoa trunk allowed vlan except 100—1000 Switch一3548(config—if)#exit
C、 Switch一3548#vlan data Switch一3548(vlan)#vlan 10 name libl0 Switch一3548(vlan)#vlan 14 name libl4 Switch一3548(vlan)#vlan 24 name lib24 Switch一3548(vlan)#exit Switch-3548#configure terminal Switch一3548(config)#interface g0／8 Switch一3548(config—if)#switchport mode trunk Switch一3548(config—if)#switchpoa trunk encapsulation isl Switch一3548(config—if)#switchpoa trunk allowed vlan 10，14，24 Switch一3548(config—if)#switchpoa trunk allowed vlan except 100—1000 Switch一3548(config—if)#exit
D、 Switch一3548#vlan data Switch一3548(vlan)#vlan 10 name libl0 Switch一3548(vlan)#vlan 14 name libl4 Switch一3548(vlan)#vlan 24 name lib24 Switch一3548(vlan)#exit Switch—3548#configure terminal Switch一3548(config)#interface go／8 Switch一3548(config—if)#switchport mode trunk Switch一3548(config—if)#switchpo~trunk encapsulation dotl q Switch一3548(config—if)#switchport trunk access vlan 10 14 24 Switch一3548(config—if)#switchport trunk allowed vlan clear 100—1000 Switch一3548(config—if)#exit

【正确答案】 B

【答案解析】本题考查的是交换机Catelyst 3500系列VLAN的配置。交换机VLAN配置的主要任务是：配置VTP，建立和删除VLAN，为交换机端口分配VLAN和在交换机端口上配置VLAN Trunk。建立VLAN命令格式：vlan<vlan ID>name<vlan name>，本题使用的是IEEE 802．1 Q协议，故排除A、C选项；设置不允许中继的VLAN命令格式：switch一3528一TEST(config—if)#switchport tmnk allowed vlan expect<vlan ID>(不允许访问的ID），排除D选项。故选择B选项。