单项选择题 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?（）

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

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