A network administrator is troubleshooting the OSPF configuration of routers R1 and R2.The routers cannot establish an adjacency relationship on their common Ethernet link.The graphic shows the output of the show ip ospf interface e0 command for routers R1 and R2.Based on the information in the graphic,what is the cause of this problem?（）

what is the advantage of policing opposite to shaping？

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

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

what is four ospf area type？

什么是NAT？

How should arouter that is being used in a Frame Relay network be configured to avoid split horizon issues from preventing routing updates?（）

Local Preference？

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

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?（）