单项选择题 In which of the following scenarios would the "show cdp neighbors detail"command be an appropriate troubleshooting tool?（）

单项选择题 Which command can be used to determine the type of cable attached to the Serial 0/0 interface on a router?（）

单项选择题 TestKing.com is configuring the serial interface of a Cisco router to connect to the router of a new ISP. A full T1 is being used for the Internet connection. After issuing the show interface serial 0/0 command, it is observed that the interface is UP and the line protocol is DOWN. Which of the following commands could fix this problem?（）