单项选择题
A. A remote physical layer problem exists.
B. The host NIC is not functioning.
C. TCP/IP has not been correctly installed on the host.
D. A local physical layer problem exists.
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 A default Frame Relay WAN is classified as what type of physical network?（）