QoS機(jī)制中的分類，采用ip數(shù)據(jù)包中的哪個字段？

What is the next state of initial in spanning-tree protocol？

A default Frame Relay WAN is classified as what type of physical network?（）

what is the advantage of policing opposite to shaping？

The Frame Relay network in the diagram is not functioning properly.What is the cause of the problem?（） 

當(dāng)將多個交換機(jī)加入到MST region當(dāng)中會發(fā)生什么（what happen）？

如何實(shí)現(xiàn)擁塞避免？

As a CCNA candidate,you must have a firm understanding of the IPv6 address structure.Refer to IPv6 address,could you tell me how many bits are included in each filed?（）

什么問題導(dǎo)致SERVER VTP密碼跟替他交換機(jī)VTP密碼不匹配？

four switches， which one will be root switch.（no pic）.