这题如何解释？

飞猴

If I have VLAN 3, and VLAN 4 configured on a Cisco Switch, and I would like to have pc’s on VLAN 3 communicate with pc’s on VLAN 4. Which of the following will allow this inter-VLAN communication to<br>take place?<br>A. It takes place through any Cisco router.<br>B. It takes place through a Cisco router than can run ISL.<br>C. It takes place through a router, but this disables all the router's Security and filtering functionality for<br>the VLANs.<br>D. For nonroutable protocols, (e.g., NetBEUI) the router provides communications between VLAN<br>domains.<br>E. Inter-VLAN communications is not possible because each VLAN is a separate broadcast domain.<br><br>答案选B，为啥还要路由器支持ISL？？

阿米巴原始虫

呵呵，，那你觉得会选什么呢<br>书没认真看吧，，在台湾人讲的CD里有专门提到，，难道你忘了？

sky

台湾人讲的CD???<br>啥呢东东???

sdspage

哈哈哈～～我也很紧张哩……

chinamoon

这实际上就是VLAN之间互联互通啊。<br>飞猴，还记得你原来设计的三层交换机么？原来二层路由器VLAN直接交换信息就是通过ISL(cisco)或者802.1Q进行的。