QoS Mechanisms：問在部署QoS中要用的3個mechanisms是什么？

Refer to the exhibit.The network administrator is in acampus building distant from Building B.WANRouter is hosting a newly installed WAN link on interface S0/0.The new link is not functioning and the administrator needs to determine if the correct cable has been attached to the S0/0 interface.How can the administrator accurately verify the correct cable type on S0/0 in the most efficient manner?（）

Local Preference？

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

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?（）

what is four ospf area type？

QoS機制中的分類，采用ip數(shù)據(jù)包中的哪個字段？

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

Which of the following describes the roles of devices in a WAN?（）

what is the disadvantage of policing？